[Slide text: Of islands and undergrads: A decade of bird study in the Isles of Shoals; Photo: Two people on a research boat and five people on an inflatable boat in water with land in the background]

[Max Witynski] Okay. Welcome everybody. I think we’ll get started. 

[Audience talking]

[Max] What? [Pause] Good evening everybody. Welcome to the Monday night seminar. Um, I’m Max Witynski, I’m a senior in biology and society here at Cornell. And tonight it’s truly an honor to introduce my research advisor Dr. David Bonter, who will be giving the seminar this evening. 

Uh Dr. Bonter, standing over there, he’s currently the Arthur Allen Director of Citizen Science here at the Cornell Lab of Ornithology. Uh a position in which he oversees programs like Project FeederWatch. Um, which is in its thirtieth season this year and has over twenty thousand uh participants reporting their sitings of backyard birds. 

Dr. Bonter got his PhD from the University of Vermont in 2003, and he’s been affiliated with the Cornell Lab of Ornithology for the last fifteen years. Uh during that time he has not only been a leader in citizen science and outreach, but he’s been extraordinarily committed to working with students. Uh Dr. Bonter teaches the field course in bird banding here at Cornell. And he’s also taught field courses in places as far away as Kenya and the Dominican Republic. Uh, Dave was on the faculty of Shoals Marine Lab on Appledore Island in Maine from 2007 to 2016. At Shoals Dave taught the field ornithology course and advised the undergraduate interns studying the island’s birds.

Uh, primarily the herring gulls, but other birds as well. 

And you’ll be hearing about all of that tonight. Dave continues to work closely with undergrads here at Cornell, uh who are interested in research. Last year he was recognized as a professor of merit in the College of Agriculture and Life Sciences for his outstanding commitment to teaching. 

Uh this is a designation that is significant because it is awarded by students rather than by faculty or administrators. 

It’s been my privilege to work with Dave for the last four years on multiple projects, uh most significantly on my senior thesis studying the migratory connectivity of yellow warblers, which you’ll also be hearing about tonight.

Dave is not only a phenomenal motivator and source of inspiration of campus, um but he’s also the epitome of a morning person.


And so it was his enthusim—his enthusiasm, not only on campus but also at 4:30 am on, on mornings in the field in Maine that resulted in the success of my project. Um, my story is just one of many that Dave will be telling tonight as he talks about his research with his students over the last seven years. Um, and since I’m sure we’re all anxious to hear what he has to say, without further ado I’ll turn the floor over to him.


[Max steps away from the podium and removes his microphone. Dr. David Bonter walks up to the podium and takes the microphone from Max, then attaches it to his sweater]

[Dr. David Bonter] All right. Thank you, Max. Um, it uh, it’s a real pleasure to uh, to be here tonight. Especially to have Max uh introduce me. Uh I challenge anyone to find a better human being among the student body at Cornell than Max Witynski. I’ve known him since he was in high school. I met him at a conference when he was in high school. And it’s hard to believe he’s, he’s going to be graduating here in, in a couple of months.

Um, it’s also an honor to, to stand here in front of the, the Fuertes paintings. I distinctly remember coming down to the Lab of Ornithology for Monday night seminars back when I was in junior high and high school, coming down from Rochester. Uh, and it was a different building then. The paintings were in a different place, but uh, it’s great to see the Monday night seminars continue.

Apparently now there are a whole lot more people online than there are in the room, so I think I have to stand still and speak into the microphone for the folks online [waves to the camera].


Um, so, uh, thanks everybody for coming out. Uh we’re about to depart on a, a virtual trip to Appledore Island, which is one of the islands in the Isles of Shoals. This cluster of islands is located uh, about an hour boat trip on a boat like that one, a research vessel like that one, out of Portsmouth, New Hampshire.


Uh being in the Shoals, even though it’s an hour from the mainland is like being in a completely different world. It’s a, a land with a long history of riches and of squalor. Of famous people and of famous murders. Uh, and maybe I can tell you about those later. 

But science and conservation now reign in the Isles of the Shoals. And I’d like to share a few of the stories uh from some of the students who I’ve been lucky enough to engage with on research projects out there over, over the past decade.

Before we get to the islands I’d first like

[Slide text: Think of a scientist]

everybody to, to think of a scientist. Imagine a scientist in your mind’s eye. Everybody have that, that image? Uh you might be thinking of somebody like Carl Sagan

[Photo: Carl Sagan]

or Mary Leakey,

[Photo: Mary Leakey on a postage stamp]

 Stephen Hawking might come to mind, or 

[Photo: Stephen Hawking]

the amazing and incomparable Jane Goodall.

[Photo: Jane Goodall and a chimpanzee]

Uh, pop-culture folks like uh Bill Nye

[Photo: Bill Nye wearing a blue lab coat and holding a globe]

or Neil deGrasse Tyson might come to mind,

[Photo: Neil deGrasse Tyson]

or if you dig even deeper back into the, the mental cobwebs, uh that crazy dude


from Back to the Future,

[Photo: Doc from Back to the Future]

or some of the best muppets that were, that were ever made.

[Photo: Muppets Bunsen and Beaker]

So now I’d like you to think, you to think about 

[Slide text: Who ‘does’ science?]

who does science? Who engages in science? Okay. You might be thinking of professors, uh PhDs, 

[Slide text: Professor]


[Slide text: Ph.D.]

Possibly lab technicians.

[Slide text: Lab techs]

Uh maybe postdocs, or grad students.

[Slide text: Postdoc]

[Slide text: Graduate student]

Uh, but what about undergrads? 

[Slide text: Undergrads!]

This evening I’ll share with you some novel and exciting research in biology conducted by Cornell undergrads. As they set the stage for their promising careers, and I’ll hopefully convince you along the way uh about the potential of undergrads, particularly here at Cornell to generate some, some quality scientific research.

And I am incredibly lucky to work here 

[Photos: Various undergraduate students working in the field or standing in front of their research posters]

at the Lab with, with people like Anne Marie Johnson. And I’ve always felt lucky to work here. But what I didn’t know when I, when I came to the Lab uh was how rewarding it would be, how exciting it would be to engage in genuine research with cohort after cohort of talented undergrads. 

And tonight I’d like to take you on a journey of scientific discover with, with some of these folks, who I’ve been lucky enough to work with.

Uh this is a collection of, of current and, and past grad students, and I’m actually just noticing the guy in the lower left there, he just defended his PhD at UC Davis on Friday, and called me up all excited about that. Uh so, so good group of folks.

Many of these students have worked out at the, 

[Slide text: Isles of Shoals; Image: Google Earth view of northeastern US with Isles of Shoals marked]

the Isles of Shoals. Uh, it, the Isles comprises nine islands

[Image: Satellite view of Isles of Shoals with each island visible]

in a, in a series of rocky ledges. Uh, again off of Portsmouth, New Hampshire. The Maine-New Hampshire state line runs right through the middle of the islands, so the northern islands are in Maine, the southern ones are in New Hampshire. 

The islands themselves

[Photo: Ocean view at sunrise with land in the distance, a splash in the water, and a northern gannet flying straight down toward the water]

are a, a cluster of, of craggy, rocks uh with little vegetation other than poison ivy. Sounds great, doesn’t it?


Uh it’s a place where nobody is or would want to be at, at this time of the year, although there might be a couple of snowy owls out there. But the islands come alive in the summertime thanks to the birds. Uh species like northern gannets are plunge-diving for fish in the cold waters of the Gulf of Maine.  

[Photo: Wilson’s storm-petrel running across water]

Wilson’s storm-petrels literally walk across the water as they’re searching for little bits of, of floating food. Uh, I’d argue that there are few

[Photo: Two male common eiders with five females in the ocean]

more inspirational sounds in nature than the sounds of eiders cooing and courting on a May, misty May morning. Uh it’s a, it’s a wonderful sound. 

The isl—the environment on the islands is,

[Photo: Group of people, most looking through binoculars, on a rocky island]

it’s alien and it’s exotic to most, to most of us hominids. But it’s the confluence of this really unique marine environment and the gobs and gobs of birds that come there in the summertime that really attracts the attention of, of researchers and students alike. 

And as Max, as Max mentioned I taught field ornithology uh at Shoals Marine Lab, which is located on Appledore Island, uh, for, for the past ten years.

And that’s a, a, an institution that’s run by both Cornell and the University of New Hampshire. 

On the islands we try to leave the classroom behind as much as possible. And get out and engage in experiential uh learning, and that learning often ends up leading to, to some publishable science. 

Students are lucky.

[Photo: Island with bird blinds and birds flying around]

Uh, they get to engage in a lot of activities that, that most people don’t, uh aren’t allowed to do in their normal lives. Uh how many people have been to a tern colony? Just a couple. Max, you don’t count.


All right, um. Well I’m gonna take you there with this little bit of a video.

[Video begins: Very noisy terns flying around the island. Camera pans to show students watching and pointing, then walking toward the terns with their equipment.]

This is on Seavey Island, which is one of the southern islands in the Isles of Shoals. Uh not much more than rock and some grasses. Uh but during the nesting season about 1200 to 1500 pairs of common terns nest on this rock, along with a dozen or so roseate terns and a, a handful of arctic terns as well. And it’s a pretty, pretty spectacular and sensory overload kind of environment. 

[Video ends]

So that might have looked beautiful. That would have been uh landing on the island in, in June. Uh, but this is what it looks like if you actually go into the center of the colony.

[Video begins: Group of students wearing jackets with hoods up while standing beneath the terns flying around and calling, with some terns swooping down toward their heads.]

It’s uh, like uh, Hitchcockian movie uh about the uh birds there. 

[Video ends] 

Uh and you may have noticed that the students were wearing raincoats. It wasn’t because it was raining,


but there was, there was something a lot more uh viscous and smelly falling, falling from the sky there.

And as you can see the,

[Photos: Summer tanager, hummingbird, painting bunting, and indigo bunting being held]

the vegetation on the islands is sparse, and few trees are larger than about twenty feet tall. Uh, as such during the breeding season the, the songbird community is, is pretty limited. We have, we have lots of yellow warblers, song sparrows, common yellowthroats, uh a few red-winged blackbirds, a couple of gray catbirds, but not much else. 

But what’s truly spectacular uh in terms of songbirds on the island is what we find during spring migration. And I have never experienced fall outs like you see on these islands in the Gulf of Maine during spring migration. 

Uh and if you’re not familiar with migration, these songbirds are flying at night, uh often they’re blown out over the open water, and uh, and at first light they have to find the nearest land uh, to, to settle down. And islands, like Isles of Shoals attract just amazing uh numbers of birds, amazing diversities of birds, and even some birds that you really wouldn’t expect. 

We banded painting buntings three years in a row on Appledore Island, Maine. It’s about 700 miles north of the nearest breeding territory for them. We’ve banded white-winged doves, summer tanagers are now becoming quite common. That’s a, that speckled bird in the upper left there. That’s a young male summer tanager that isn’t quite red yet.

Uh, I recall, one of my most vivid memories on the island was, was one really nasty, misty, late May morning and I was inside lecturing, and lecturing, and just giving every lecture that I could possibly give, and finally one student said to me you know Dave I’m not tired of hearing you talk, I’m tired of hearing you talk inside. So uh, so we went out, we went out into the miserable weather and there were birds everywhere. 

Every bush had four or five species of warbler in it. We went down to the intertidal zone, and there were these mats of floating seaweed, on which blackpoll warblers, bay-breasted warblers, Blackburnian warblers, were hopping around, eating the only insects that they could find as those insects were coming out of the, the water.

Um one of my students sat down on a rock, and a Blackburnian warbler landed on his boot and just rested there for a while. So just, incredible experiences during, during migration uh on the island. If you’re there on the right day. 

And as wonderful as the, the birds are,

[Slide text: Ornithology Interns; Photos: Various interns on the islands, some holding birds]

uh my most vivid and rewarding memories of my time at the Isles of Shoals was the, have to do with this long lineage of inquisitive and dedicated ornithology interns. And there are, are too many stories to tell but I’d like to share a few with you this evening.

[Slide text: Great Black-backed Gull Larus marinus, Herring Gull Larus argentatus; Photos: Great Black-backed Gull and Herring Gull]

And while not generally considered the, the cream of the crop uh in the bird world, uh the stars of the ornithological research show out in the Isles of Shoals are certainly the gulls. Uh so we’ve got the great black-backed gull there on the left. Uh this is the largest gull in the world. They always look grumpy like that. 

Uh and on the right is uh the, the littler cousin, the herring gull. Uh about 1500 pairs or so of herring gulls nest out uh in the Isles of Shoals, and somewhere between 300 and 500 pairs of the great black-backed gulls.

These gulls come to the islands 

[Photos: Life cycle of a herring gull from eggs (Egg Stage) to small chick (Day 6-7), larger chick (Day 15), fledgling gull (Day 45), and adult gull back to eggs] 

to avoid mammalian predators that could threaten their, their nests and eggs on the mainland. Uh and from, fortunately from our perspective their, their nesting season coincides nicely with summer vacation here at, at the university. So students can go out to the island, start studying these birds, and see the entire reproduction uh stage happen during their summer on the island. 

It takes about 45 days for a herring gull chick to go from hatching from the egg to flying.

We band as many of the birds as we can

[Photos: Gull with metal band on one leg and black PVC band with 4H5 visible on the band on the other leg, and zoomed in view of the PVC band]

to allow for individual identification. And we don’t just use the metal bands, uh leg bands that you might be familiar with. We also uh, attach those field-readable bands as well. Those are made out of PVC with three unique letters and number uh scribbled into each of those bands. 

So just looking at the bird from ten or fifteen feet away you can identify who that individual is without ever having to recapture that bird. With binoculars or a spotting scope you can identify individuals from, from many, many yards away.

And Julie Ellis one of my great colleagues at Tufts University has been banding the gulls out there for, for, uh, oh, I’m not going to say how long because she’ll be mad at me.

So these field-readable bands

[Slide text: Odile Maurelli Class of 2017, Winter locations Appledore Herring Gulls Red = Female Blue = Male; Photo: Odile Maurelli in a lab; Maps: Winter locations of Appledore Herring Gulls, showing gulls in Texas, Florida, New Jersey, and up the east coast; Separate maps of males and females around Massachusetts, New York, and Connecticut]

have allowed us to, to tap into observations from the public, citizen scientists all up and down the uh Atlantic seaboard who are seeing our birds and calling in and reporting those bands to us. 

And on, on the left of the screen there is Odile Maurelli, and Odile is a senior working on her, her senior thesis here right now. Absolutely horrified by the way that she is going to be graduating in a couple of months because Cornell is so great. 

Uh but Odile has been taking blood samples from the birds that we band on Appledore, and identifying, using genetic techniques to identify who’s male and who’s female. In gulls the males and the females look similar, and the only way we can definitively say who’s a male and who’s a female is by using genetic techniques. 

And just down the hall here at the Lab of Ornithology we have the Fuller Evolutionary Biology Lab, and that’s where Odile has been uh, running the analyses there. And basically what she’s find is uh, uh, I’ll let the cat out of the bag here, is that females are going a lot farther away from the nesting colony than the males. 

Males are, are homebodies. They rarely travel farther south than about Long Island, uh but we’ve had some of our female gulls showing up as far south as Brownsville, Texas. 

And this, this scene may be a bit familiar to some of you

[Slide text: Photo by Kevin McGowan; Photo: Gulls standing on a compost pile, one great black-backed gull with bands visible on its legs]

if you’re a hardcore birder in the Ithaca area. This is taken at uh the Cornell compost piles by our own Kevin McGowan about ten days ago. And if you focus on that large black-backed gull in the center of the photo there, uh that bird has some bands on its legs.

And that is actually a bird we banded on Appledore Island last May. Uh it’s the second bird that we’ve banded on Appledore that has shown up at the compost piles at Cornell.

And it’s a little bit spooky that they’re following me, 


but, but cool to see our birds showing up here. 

And although

[Photos: Gull chicks, including one hatching from the egg]

it takes a, a special birder like Kevin to, to really appreciate adult gulls, uh pretty much anybody uh will be taken in by the charm of gull chicks. They’re adorable, they’re cuddly, they’re clumsy. My students claim that they’re better than puppies or kittens, uh for at least the first two or three days of their life. 

After that they enter an extended, ugly, smelly teenage stage.


But they’re really cute when they first hatch.

And apparently they’re also quite tasty. 

[Photo: Great black-backed gull with a gull egg in its beak]

Uh gull chicks and eggs uh are uh the subject of a lot of predation on the islands, and, and uh although these birds nest out on the islands to avoid mammalian predators, and they nest in these dense colonies with other gulls to drive out any predators that may come into the colony, uh those birds that they’re collaborating with one minute to drive out predators can actually become the predators the next minute.

Uh as we probably all know from McDonald’s parking lots, and going to the beach, gulls are incredibly opportunistic. And any egg or chick that’s left unguarded will be, will be snapped up pretty quickly. Like, uh, this is a great black-backed gull stealing one of its neighbor’s eggs.

And if you land on a 

[Slide text: Dive Bombing Kelp Gulls – Filmed by Greg Morgan; Photo: Blue sky with some clouds and two gulls]

gull nesting colony you’ll be, you’ll soon learn that these gulls are not passive bystanders uh around their nests. In fact they can be quite vicious and vigorous defenders of, of their nests. And it makes sense, because they are investing a lot of energy in this reproductive effort. They only get one chance at breeding each year. Uh so if something comes along and, and eats their eggs or chicks it’s, it’s a big deal.

And this is how they defend their nests.

[Slide text: Dive Bombing Kelp Gulls – Filmed by Greg Morgan; Video: Kelp gulls vocalizing as they fly in and swoop down, dive bombing the camera, then a dive bomb in slow motion]

So they engage in this dive bombing behavior, often they’ll be defecating and splattering you will poo, uh vomiting on you, uh just the noise. Sometimes they do make physical contact. This is a very effective deterrent. Uh and, and any of my students who have been out to Shoals if they hear that waaa sound they immediately just like cringe and duck.


Um, yeah, so these are kelp gulls, but all gulls respond in the, the same way. Which brings me to

[Slide text: How do gulls identify and respond to threats? Sarah MacLean, Natural Resources, Class of 2013; Photo: Sarah MacLean holding a gull chick]

uh, another student project that I’d like to, to detail a little bit. 

I’d like you to meet Sarah MacLean. Uh she graduated back in 2013. She was actually the, the SUNY chancellor award winner as the best student in all of the College of Ag and Life Sciences that year. 

And, and I like to think that science is about asking and trying to answer questions. And I find that the best way to develop those questions is to actually get out in the field and start watching, and seeing what’s going on.

Many of my students start out this way. They go out in the field, they make an observation, they ask a question. They dig into the scientific literature uh and develop the methodology required in order to collect the data to answer that question.

Sarah came to Shoals the summer after her freshman year and was enamored by the gulls, and the range of defensive behaviors that they displayed. And she was, she was wondering how, how it is that they identify and respond uh to different threats around the nest.

She was interested in digging into

[Slide text: -Visual cues

-Auditory cues

-Predator initiated

-Conspecific alarm calls

-Heterospecific alarm calls; Photo: Gulls standing on rocks on the island]

questions about gull cognition, uh what cues do they use to recognize potential threats. Obviously a predator walking up to a nest is a visual cue that the birds will react to. But are there other ways that they can identify uh potentially dangerous scenarios and situations? 

Can they use auditory cues? Noises made by the predator themselves? Or possibly alarm calls from their neighbors of the same species or of different species?

And these defensive behaviors that you saw in that, that last video take a lot of energy. It doesn’t make sense for birds to, to freak out and attack whenever there’s any little disturbance in the colony. That’s costly. But if they don’t respond to a serious threat then that’s obviously dangerous as well. 

So Sarah was interested in whether or not gulls respond more vigorously to more serious threats. And in order to, to get at this question she designed

[Slide text: Sound playback experiment

Song Sparrow Non-threatening, familiar

Western Scrub-Jay Non-threatening, novel

Alarm calls Conspecific Heterospecific

Human voice, Potential threat

Bald Eagle Potential Threat; Photos: Song sparrow, western scrub-jay, herring gull, cover of Jonathan Livingston Seagull by Richard Bach, and bald eagle attacking gulls in flight]

what’s known as a playback experiment, to expose birds to a whole bunch of different stimuli and then record how they react. One of the stimuli that she, she offered up to the birds was the song of a song sparrow. This is a completely non-threatening uh auditory cue. There are song sparrows nesting everywhere on the island, uh absolutely not a threat to the birds.

Sarah was interested in neophobia, or fear of the new, and how the birds would respond to a novel sound that was non-threatening but something that they’d never heard before. And so she played songs from the western scrub-jay uh to the gulls. These are, this is a bird that would never be, be seen nor heard by, by gulls in the Gulf of Maine. 

Sarah also played back alarm calls of both herring gulls and great black-backed gulls to herring gulls. And then she really up the ante and played back uh, the human voice. This, these were recordings of other students reading a passage from Jonathan Livingston Seagull. She thought that was funny. Uh, as well as vocalizations of bald eagles. 

And humans remain, have been historically and remain the biggest threat uh to gulls in the Gulf of Maine. They’re still widely shot and discouraged from nesting, so nests are, are destroyed on a regular basis by, by people who don’t want them nesting near their homes. 

And bald eagles, since the DDT era back in the 1960s have made a truly remarkable recovery, which most of us are happy about. But if you’re a seabird you’re not so happy about it. Bald eagles are becoming quite a problem in seabird nesting colonies on both the Atlantic, and Pacific, Pacific coast. 

So we played back, Sarah played back all of those different sounds to the birds, and she recorded the reaction of the birds, uh which engage in

[Slide text: Rating Responses, 0 1 2 3 4 5 6 7 8; Photos: Gull sitting on a nest (0), gull looking around (2), gull standing and calling (4), gull flying (6), gull dive bombing (8)]

a set of very stereotypical behaviors. So, so a gull can just continue to sit on a nest and, and incubate and not pay any attention. Uh if they’re a little bit interested they’ll stretch their neck up, and look around and scan for, for what’s making that sound. 

Uh stepping up the ladder they’ll get up off the nest and walk around, they may even give these little kek, kek, these mild alarm calls. If they’re really irritated they’ll start looking for the potential threat. And then uh, sort of the nuclear option is when they do that diving and pooping thing. 

And what Sarah found was that the, the

[Slide text: Herring Gull: Intensity of response is related to severity of the threat; Graph: Intensity of Response by Stimulus; Photo: Gull calling]

intensity of response by the herring gulls was indeed related to the severity of the threat. So on the graph here you can see on the vertical axis how intense the response was. Zero means they couldn’t care less, seven is that nuclear option. Along the, the horizontal axis we have the different cues to which the birds were exposed. 

So song sparrow song, as we expected had little reaction in, in the gulls, caused little reaction. Western scrub-jay this, this is that novel sound, peaked their interest but they didn’t bother to get up off the nest. When we started to play back alarm calls, that got the birds a little excited. They got up off the nest, started to look around. Tried, tried to set eyes on the potential threat. 

The bald eagle call was sort of right on the alarm call range. We were a little surprised by that. We anticipated that would, would elicit a stronger response. But in hindsight that, that makes a lot of sense because when a bald eagle is attacking it’s not vocalizing. So we think there was a mismatch between hearing the sound of the bald eagle and, and interpreting that as a, as a threat.  

But what really got them riled up was the human voice. These birds did not like hearing a human and not being able to see where that person was. And then of course the person walking up to the nest to set out the speakers, and retrieve the speakers elicited the strongest response. 

So Sarah’s work uh led to three uh scientific papers uh that got her into a PhD program at UC Berkeley in conservation biology, and she’s working on that now. And will, will hopefully be Dr. MacLean very soon.

And after spending uh, 

[Slide text: Encoding the alarm signal: Risk-based alarm calling in Herring Gulls

Shailee Shah, Biological Sciences, Class of 2014; Photo: Shailee Shah wearing a bike helmet and standing with her arms out on the island]

a couple of summers really getting to know gulls and their alarm calls on the island, Sarah noticed that the, the vocalizations seemed to be more nuanced than, than people and researchers have previously recognized. 

We have one word to describe the alarm call of the gull, it’s the yeow call, and you’ll hear that in a minute. To us a yeow is a yeow, but Sarah’s wondering if, if, if that alarm call is actually something more. If there’s something more, more information in there.

And that’s where uh this delightful young woman, Shailee Shah, uh picks up the story. 

The big picture, what Shailee uh was interested in

[Slide text: Photos: Andy Johnson, Steve Baranoff, Chuck Tague, Gerard Dewaghe; Photos: Male summer tanager singing with a cartoon speech bubble with a musical note in it above him, female summer tanager, male summer tanager on a branch with speech bubble saying “Here!”; nestling with speech bubble saying “Hungry!”; Chickadee with speech bubble saying “Watch out!”]

is how birds use vocal communication to convey a variety of information and signals to one another. So we know that a songbird could sing, a male songbird may be singing, and he might be saying hey baby, I’m over here. Come, come check me out. Or he might be saying hey dude, this is my territory, you stay out. So he’s conveying both of those bits of information in his song.

A lot of birds give contact calls to maintain flock cohesion. At a certain age they can give begging calls to elicit a feeding response from their, from their parents. And all birds out there give alarm calls of one sort or another. Warning others to look out for, for uh danger. 

And there’s been plenty of, 

[Slide text: Songbirds can communicate not just “predator!” but also kind of predator

Terrestrial vs. aerial predator

Threat level; Images: Cartoons of small birds with a larger bird flying over them, and two birds counting off on a piece of paper the number of “Dee” calls another bird is making]

of research in recent years that shows that contained within those alarm calls, those birds aren’t just saying danger or watch out. They’re saying danger hawk, or danger snake. And the other individuals in the flock understand that and respond in a appropriate manner.

In fact the chickadee call, the chick-a-dee-dee-dee-dee-dee, that’s actually an alarm call. And we know that the more dees on the end of that chick-a-dee-dee-dee-dee-dee means that that bird is really, the more dees, the more upset that bird is, and the more dangerous the situation is.

So these birds are encoding information in their calls. Which brings me back to the herring gull.

[Slide text: The ‘yeow’ call; Photo: Herring gull standing on a rock]

This is what the yeow call of a herring gull sounds like.

[Video: Herring gull standing on a rock, with a yeow call audible in the background, then the gull on the rock starts making the yeow call]

So you could hear the, the higher pitched yeow of the herring gull, in the background you might have heard some more lower pitched yeow calls. Those were from great black-backed gulls. It’s essentially the same call, uh just different sized birds produce that different pitch.

And Shailee’s first question was

[Slide text: Do gulls change their ‘yeow’ call? Images: Diagram of person standing more than 15 m from a gull on a nest which is low threat level, and high threat level with a person standing less than 5 m from a gull on a nest]

whether or not gulls change their yeow call depending upon the level of the threat. And to test this question she recorded calls of a nesting herring gull as a person walks towards the nest, starting about 15 meters away where they would just start to, to say yeow, uh until the person got right up to the nest. 

And she did this for a lot of different nests. Uh analyzed all of those sounds, uh using a program called Raven, which is sound analysis software developed here at the Lab, uh to test for differences in the calls. 

And these two calls

[Slide text: The ‘yeow’ changes with risk; Photo: Herring gull in flight; Graphs: Spectrograms of Low threat level (LTL) and High threat level (HTL) yeow calls showing Frequency (Hz) over Time (ms)]

uh, so, so Raven transforms that sound into a visual representation like you can see on the screen here. And those two sounds were produced by the same individual gull. 

Uh the, the graph on the left shows the call, the yeow call when a person was pretty far away from the nest. The graph on the right shows the call when the person is right up to the nest. 

The horizontal axis is time, the vertical axis is the frequency of the, the call. 

So I’m guessing that most people just looking at those two graphs not knowing anything about how the sound analysis works, you can probably look at those and think okay, they’re different, right. They look, they look different. But do they sound different?

Let’s take a look, starting with the low threat level, that graph on the left.

[Audio: Low threat level yeow call]

And high threat.

[Audio: High threat level yeow call]

Back and forth. 

[Audio: Low and high threat level yeow calls]

So low, high, low, high, okay.

Do you hear the difference?

Yeah, there’s a difference there.

So first Shailee found that the rate of calling increased as the level of threat increased, or as the person got closer, the birds made more yeow calls in a shorter amount of time. And the calls themselves changed in, in structure and in pitch, and had that little break in the middle under the high threat scenario.

And to demonstrate, so, 

[Slide text: Do listeners respond appropriately?

-High threat + 1 sec intervals

-High threat + 3 sec intervals

-Low threat + 1 sec intervals

-Low threat + 3 sec intervals

-Song Sparrow song (control); Photo: Song sparrow; Diagram: Gull on nest with speakers ~ 2 m away and Video Camera nearby]

so the next question is. So yeah, they’re they’re creating these different yeow calls, but do their neighbors, do their mates, do other individuals of the same species understand what these different calls mean?

And in order to answer that question Shailee developed another playback experiment where she put a speaker out by a nest, this time put up a video camera to record what the birds were doing. 

She set up a series of playbacks, one that was the high threat level call at a really rapid pace—rate, high level call at a sort of relaxed, slow rate, low threat level call rapid rate, low threat level call at, at a slow rate, and then a song sparrow again as, as a control. 

And she again recorded how the birds responded, just as uh, Sarah MacLean did in, in the previous study.

[Slide text: Gulls responded most urgently to high threat level calls at a high call rate; Graph: Mean Response Urgency by Playback Type (Chi-Square = 11.87, P = 0.018, N = 14)]

So again the gulls responded with, with mild or almost no interest to the song sparrow call. Low threat level calls instigated a greater response, the birds often were, were perked up and looking for predators. Some of them would get up off the nest, stand by the nest and look around. Uh, the timing didn’t seem to matter too much. 

But the high threat calls played in quick succession really got the birds riled up, uh causing them to get up off the nest, they often took flight and started circling around, looking for something or someone to attack.

So Shailee clearly demonstrated that herring gulls encode the level of threat in their alarm calls. That both call type and call rate uh convey information about the urgency of the threat. And that the, the strength of the response to those alarm calls depends upon the level of urgency encoded in, in that message.

And Shailee uh published this work in Animal Behaviour, which is a scientific journal. Uh the top, uh journal in the field of animal behavior. And she is now working on a PhD at Columbia. Uh yesterday she was texting me from East Africa, photos of rhinos and elephants and kori bustards and, and uh, she’s about to begin six months of research on superb starlings in Kenya. So look forward to see where she ends up in the future. 

Okay, as I, 

[Photo: Blurry view of grassy area]

as I mentioned earlier spending time in the field is a, is an excellent way to develop research questions, uh by, by watching and observing it’s pretty impossible for us to not start asking questions. And this next study responds—uh results from a unexpected and a rather horrifying observation. And my students told me, right Max, that uh I need to give a warning here.

If, if unpleasant images uh, upset you look away, and I’ll tell you when it’s safe again, okay. And I’m gonna start playing this video.

[Video: Herring gull nest with dead chick covered in ants, with adult gulls calling]

This is a herring gull nest, and if you’re looking you might see an egg and a chick, and lots of little things crawling around. Those are uh an invasive ant called Myrmica rubra, the European fire ant. 

And this guy Luke DeFisher,

[Slide text: Invasive ants and gull reproduction

Luke DeFisher, Biological Sciences, Class of 2013; Photo: Luke DeFisher holding a chick]

uh one of my interns on Appledore a few years ago, noticed that there were ants in a lot of these nests and started to wonder how the presence of ants might be influencing the reproductive success of the gulls.

These are fire ants. If you’ve been to the beach in uh, coastal Maine, they’re a big problem there now. They were introduced back in the ’70s. Now populations have grown quite, quite large. If you’re bitten by these it burns, it’s nasty. Uh, so Luke spent the summer getting bitten by fire ants, and, and monitoring um a whole bunch of gull nests.

[Slide text: European fire ant (Myrmica rubra); Photo: Gull chick with fire ant on its beak, circled in yellow]

There’s the, there’s the culprit right there on the beak of that chick, Myrmica rubra. So Luke followed about a hundred gull nests throughout the nesting season. He recorded their hatching rates, the chicks’ survival rates, the growth rates, and whether or not ants were detected in the nest.

And Luke clearly documented that ants can kill newly hatched chicks.

[Slide text: Ants can prevent hatching, kill chicks and reduce growth rates; Graph: Weight (g) versus Chick Age (Day) in nests with ants and no ants]

Uh in fact they’ll even crawl into eggs as they’re hatching. So as the chick makes a little hole in the egg the ants crawl in and start attacking it, and, and kill the chick before it even hatches. 

Uh he showed, the graph there shows differential growth rates between chicks being raised in nests with ants and chicks in nests without ants.

So quicker growth in the nests without ants. Uh but the good news is that these ants require soil. And the vast majority of gulls out on the Isles of Shoals nest out on the bare rocks. So the only nests that were being affected were those birds that were nesting around the buildings and in the the vegetation, which is a relatively small fraction of the, of the birds. 

So Luke uh, published this study as well, uh graduated with honors, and he translated his interest in science to a career in the science of cider-making and distilling 


and now works for Apple Country Spirits, his family, his family’s business, and produces Rootstock Cider, which is available down at Wegmans. I highly recommend it.  

Okay, so, uh,

[Photo: Great black-backed gull chick standing on a rock]

a bit of break after uh, the somewhat depressing news about chicks being an eaten alive by ants. This is just a gratuitous shot of a great black-backed gull chick. And some, some beautiful gull eggs.

[Photo: Three gull eggs in a nest, one dark with spots and two light]

Another observation that students uh often make after even just spending five minutes in a gull colony is that the eggs come in a, a stunning array of colors and spotting and sizes, and there’s a lot of diversity there. 

And all of the eggs in this nest were laid by the same female. And sort of the, the typical egg coloration is the egg on top. So that dark olive background with the brown speckling, uh but the females can lay eggs that are more bluish or greenish with various amounts of speckling as well.

[Photo: Three different gull eggs in a nest, all light but different shades]

So you can see in that nest there has very little, uh very few uh dark spots. And then occasionally we get some really, really strange

[Photo: Two dark gull eggs and a tennis ball in a nest]

uh eggs.


And uh, and these birds they’re, they’re not the best at recognizing their own eggs. They will incubate anything.


That was not a plant. We found a tennis ball in a gull nest. 

It did not hatch, no.

[Slide text: Why are gull eggs so variable?

Michelle Moglia, Biological Sciences, Class of 2014; Photos: Michelle Moglia and Shailee Shah sitting on a tree branch, and three different colored gull eggs in a nest]

Um, so, so these observations led Michelle Moglia here on a, on a tree branch with Shailee, to try to understand why there’s so much variation in, in coloration in gull eggs. Are darker eggs better camouflaged, perhaps?

Does egg color indicate something about the quality of the female or of the pair? Is egg color related in any way to the survival of the egg or the chick that comes from that egg?

And the first step is to quantify in a,

[Photo: Four gull eggs of varying colors, each next to a ruler]

in a defensive and repeatable manner the color of, of each egg.

And egg color, all egg colors on the planet uh are determined by two different pigments. One is called biliverdin, and that’s responsible for the blues and the greens in eggshells. The other is called protoporphyrin, and that’s responsible for the darker colors, the browns. And it’s just different proportions of those pigments in the eggs that determine uh all egg colors.

And so Michelle wanted to, to quantify that.

[Photo: Michelle holding an egg looking out a window of a pop-up tent]

And we used a, a, a device called a spectrophotometer to quantify the amount of light reflecting off of the eggshell surface across the entire color spectrum. And Michelle and I spent way too much time one season in this little pop-up tent out in the nesting colony just measuring the color of hundreds and hundreds of, of eggs.

And then Michelle followed uh fate of each of those eggs through uh the nesting season.

And this is,

[Slide text: Eggs change color in the laying order; Graph: % Transmittance by Wavelength (nm) of Egg 1, Egg 2, and Egg 3, with color chart showing corresponding colors of different wavelengths]

this is what the output from the spectrophotometer looks like. Uh this graph shows uh the coloration of three different eggs from the same clutch, so these three eggs were laid by the same female. The, the horizontal axis there shows the wavelength. Uh so that’s the entire color spectrum on the x-axis, and the vertical axis shows the amount of light being reflected back at each of those wavelengths. 

So there are three eggs here. The, the egg one and two, uh those lines are essentially overlapping. So to our eyes, those eggs look identical. We wouldn’t be able to say this egg looks different from that egg. 

But that blue line you can see is quite a bit higher than the other two. That means there’s a lot more light reflecting back in a big section of that color spectrum on that egg. So that egg’s brighter. That would be a much bluer, lighter egg to, to our eyes.

And we can see, uh, in that box

[Black box added to previous graph from about Wavelength 400 to 750 nm]

that’s what our visual system allows us to see, right? So the red, blue, green, that, that whole spectrum. Birds have another cone in their vision systems. They can see in the UV spectrum. That’s what birds see.

[Pink box added to previous graph from about Wavelength 300 to 750 nm]

So there’s an awful lot going on. If you look down in that UV portion of the spectrum from about 325 to about 400. That’s an area that we can’t even begin to perceive, but there’s an obviously a lot going on there, there’s a lot of information there. So these eggs are looking very different to, to the birds than they are looking to us.

And ultimately, well and I just want to highlight this box here too.

[Black and pink boxes removed form previous graph, and teal box added from about Wavelength 450 to 600 nm]

So you can see right there that’s, that’s in the blue-green range, and there’s a big difference between those lines there. So that, that top line shows an egg that’s a lot bluer and, and greener. 

And what Michelle found was that the third egg to be laid by a female was much more likely to be that bright, pale egg. Uh females were therefore investing fewer resources. Those pigments are costly to produce. And the females have a limited amount of those pigments to put into the eggs. And so they were investing fewer resources in, in those third eggs.

Uh chicks from third eggs were less likely to, to survive overall. Uh but chicks from pale third eggs and dark third eggs sort of had equal lousy survival probabilities.

So what Michelle thought was that these birds were essentially running out of ink. They have to produce three eggs in four or five days. They’re putting a lot of energy into those eggs, and by the time that third egg comes along, their resources are depleted. 

So Michelle spent two summers, and this, I mean Michelle’s this hundred pound, you know, little petite girl spending two summers in a colony of great black-backed gulls. I don’t know how she survived it, uh, but I think it, it prepared her well for life as an investment banker on Wall Street,


uh where she is right now, and hopefully making gobs of money and she’ll hopefully remember us a few years from now.



[Slide text: Defending the weak: examining temporal patterns of nest defense in the Herring Gull

Taylor Heaton Crisologo

Ecology and Evolutionary Biology, Class of 2016; Photos: Taylor Heaton Crisologo holding a gull chick on the island, and a gull chick]

And this is the, the last gull study, I, I promise. Uh and this is an update on if you came to a Monday night seminar last March here at the Lab of Ornithology you heard uh Taylor Heaton talk about her uh research. Taylor has now graduated and, and moved on. 

But Taylor was really interested in parental defense behaviors,

[Slide text: Chick mortality is greatest when chicks are young; Graph: Predicted 5-day survival probability of chicks by day from Egg to Day 31-35 with Day 1-5 and Day 6-10 highlighted in red; Photos: Herring gull eggs and immature herring gull in flight]

and how these birds respond to threats to their chicks. And the first thing she did was to, to quantify when during the chick stage these guys are vulnerable. Uh and the graph there shows survival probability on the vertical axis, uh throughout the, the chick development stage. 

So from days one to five and six to ten there’s a lot of mortality happening. Only about one in five, sorry one in five chicks dies during those first five days of life. It’s also bad during the second five days. So that red zone there, that’s the, that’s the danger period. 

And, Taylor conducted behavioral experiments with the adults to determine how aggressive they, to measure their aggressivity, if that’s a word. To measure how aggressively they defended the nest in different stages of the chicks’ development. 

And she found that the parents are incredibly aggressive when the chicks are most vulnerable. So during those first ten days the parents are, are violent defenders of their nests. Once the chicks start walking around, reach their teenage years, uh the parents sort of lose interest and the chicks are sort of on their own. The chicks can sort of hide in rock crevices, uh but the parents are really defensive during those, those first few days.

And Taylor’s manuscript was just published last month, uh in a, in a journal called Ethology, uh which is, which is great news.

Okay, that’s the end of the gulls.

[Photo: Lighthouse at sunrise]

Uh, but before I, I wrap up I wanted to, to highlight some work conducted by students who some would say are, were smart enough to not study gulls. Uh and, that’s just a nice shot of the lighthouse out at the Isles of Shoals.

[Photo: Liam Berigan on the island]

But this is Liam Berigan who is a senior in my lab group now. And I’m going to let Liam tell you about his project.

[Video begins: Liam talking about his project with gulls flying and calling in the background.

[Liam] Hi, I’m Liam Berigan, uh Cornell class of 2017. I’m the gull intern on Appledore Island for Shoals Marine Lab uh the summer of 2016. Uh I’m doing uh eider surveys on the island. So what I’m doing is going around the islands trying to find as many of the eider nests as possible. And when I find an eider nest, I’m taking a GPS point there, and I’m recording how high the vegetation is, uh where the eider nest is, the type of vegetation, and how well the eider nest is concealed. 

And the idea is that I can take this data later, put it into a computer and try and determine uh what types of vegetation that the eiders like to nest on in the island.

Video ends]

[David] That was only the second take, so I was pretty proud of Liam on that one.

[Photos: Two eider nests with eggs partially hidden by vegetation]

Um, eiders are uh really intriguing birds. They’re beautiful birds but they’re really hard to study. Uh they, they nest in, in briars, in poison ivy patches. Here are photos of two nests. Really large eggs. The nests themselves are made out of eider down that the female plucks from her breast.

Uh males are complete deadbeats. They have nothing to do with, with the reproductive effort. Um, and, uh, once the ducklings hatch, the females take them right to the water where they begin feeding uh on their own. 

They’re incredibly precocial. So they’re walking, and swimming, and feeding on their own right from the beginning. They just need the, the parents to defend them. But uh in the Isles of Shoals it appears as though most of those eider ducklings are ending up in the stomachs of gulls. 

But we don’t quite understand what’s going on, because it seems as though the eider populations are stable or increasing, even though reproduction is almost nil. Uh so it’s something that, that it would be great to study more but they’re very difficult to study.

Here’s another uh

[Photo: Liam in vegetation while holding an eider egg with a crack in it and a GPS]

short video clip from, from Liam showing uh the, the really large eggs that these ducklings come from.

[Video begins: Liam holding an eider egg

[David] What do you have there, Liam?

[Liam] Uh this is an egg, a eider egg which is starting to pip. Like you can kind of see the bill coming through now. Uh as it pushes its way out with its egg tooth.

Video ends]

[David] And if you’re observant you can see that Liam’s hand is right on a clump of poison ivy. 


He spent the entire summer finding eider nests and going through these briars and poison ivy patches and uh survived, which is miraculous.

And what he found was uh just in one small section 

[Slide text: n = 204; Photos: Satellite image of Appledore Island, and a blown up view of the southwest corner of the island with eider nests marked by red dots]

of the, the southwest corner of the island Liam found 204 eider nests. And to give you an idea of the size of this. This area, the footprint of this area is roughly the size of the footprint of the Lab of Ornithology.

So if we just walked around the first floor of the Lab right now, imagine finding 204 eider nests in that area. And these things are pretty hard to find, so chances are there are few more in there that, that he couldn’t find. So all those red dots there represent eider nests that, that Liam uh found in that poison ivy uh briar tangle this summer. 

There’s some interesting clustering there. A lot of these birds nest really close to one another, sometimes the nests are even touching each other. 

We’ve also spent some time

[Photo: Student holding a barn swallow with one wing spread]

studying a rather unique population of barn swallows that, that nest out in the Isles of Shoals. Uh it’s unique because the nesting phenology in the Gulf of Maine is, is quite delayed. 

Uh the water, uh around the islands never gets warmer than about 53 or 54 degrees. That means that leaf out on the vegetation is much later than on the mainland, uh the insects arrive later than on the mainland. There’s less food for, for the barn swallows.

So our barn swallows on, on Appledore Island uh start nesting at about the time that the birds on the mainland ten miles away are fledging their first clutch. So our birds rarely are, are able to get two clutches of, of chicks out uh per year. 

And this is uh Collin Hertz

[Slide text: Are male barn swallows ‘good’ dads?

Collin Hertz, Class of 2015; Photos: Barn swallow nest with adult perched on the side and nestlings begging, with red arrow labeled “Antenna” pointing to an antenna around the nest; and Collin Hertz holding a barn swallow fledgling]

who graduated uh back in 2015. Collin was really interested in the provisioning behavior of birds, and that’s, that’s how mom and dad bring food to the chicks. 

And, uh, you know, as we, as we know in, in most animals uh the females do most of the work, right? Right? Females do most of the work uh and, but what uh Collin was interested in was whether or not and to what degree the males were actually helping out in raising these chicks. The females do all the incubating, but once the chicks hatch the males do uh visit the nest and bring food. 

The problem is it’s really hard to study provisioning behavior. Uh imagine sitting in a blind in a dark crevice underneath a building trying to watch a nest hour after hour and see who comes in and who’s bringing food and so forth.

Uh so we ended up using a technological solution. Uh there’s an antenna around the, the top of that nest there. Uh which recorded radio frequency identification tags, or pit tags. So we put pit tags, these little transmitters on the male and the female. And then had the antenna on the nest so that every time a parent came to the nest to feed the offspring we, we knew who it was and what the time was. 

All right, so do you think dads pull their weight?


They try, they try.

[Slide text: Male barn swallows (don’t quite) share the work; Graph: Detections Per Hour for Hours 4 to 21 of Female and Male]

So the male barn swallows are uh providing a lot of foods, food to the chicks. Uh, not quite as much as the females, the females are the, the open circles there, the, the marks on top.

Uh the males are coming quite a bit, just not quite as much as the females. 

And we did notice a lot of variation among the males. Some were pretty good dads, some were pretty lousy dads. Some fed chicks  in multiple nests. And if you know much about swallows, you know that they tend to be, among the players of the bird world.


And, and those males likely had pat—paternity in multiple nests, and it’s possible that they’re feeding multiple nests because they had chicks in multiple nests. 

We don’t have the blood samples to, to actually prove that, but I think it’s a pretty good hypothesis of what’s going on, and, and provides an interesting question for, for some future research out there.

And if anybody has ever worked with

[Slide text: How do mites affect barn swallow reproduction?

Facundo Fernandez-Duque

Class of 2018 (maybe…); Photos: Mites next to a dime to show size, and Facundo Fernandez-Duque weighing something on the island]

swallows, or had them nesting around their home, uh you probably know that as far as birds go, swallows are pretty filthy. Uh they, they deal with a lot of ectoparasites, lice, and fleas, and mites. And it’s these mites that can be particularly problematic in swallow nests.

Um we’ve even documented several instances of, of chicks in nests that are just full of mites just leaping out before they’re ready to fledge, essentially committing suicide because they’re being swarmed by the—by these parasites.

And so this is Facundo Fernandez-Duque who may or may not graduate. Um, tell him I said that.


Um, so, Facundo spent uh a summer out on the island two years ago, uh looking at how mites influence reproduction in, in barn swallows. 

And he found that 

[Slide text: Swallow chicks grow less quickly in mite infested nests; Graph: Mean weight (g) versus Day after hatching from Day 3 to Day 13 of chicks in nests with Extensive Infestation and Limited Infestation of mites; Photo: Two swallow chicks, one noticeably larger than the other, in a person’s hand]

barn swallows being raised in nests with lots of mites uh had much slower growth rates that barn swallows in mite-free nests. So, age again along the horizontal axis, the weight of the birds along the vertical axis. 

And at the end of 13 days, these birds fledge around 15 days old, but at the end of 13 days there’s about a ten percent difference on average in weight between birds in mite nests versus uh nests with few mites.  

That’s big. Ten percent difference is huge. We know from a lot of research in birds that the weight of a chick at fledging uh has cascading consequences for, for the survival of that chick in the post-fledging period and its ultimate, ultimate uh success throughout it, its life.

The photo there is a pretty scary photo showing two barn swallow chicks from different nests. Those chicks are the same age. The upper chick was from a nest with lots of mites. The lower chick is from a nest with no mites. So you can, you can really see there how, how high ectoparasite loads can influence reproduction.

And so although studying, studying lice and mites isn’t the, the sexiest of, of projects out there, uh there’s a lot to learn. And, and Facundo worked, Facundo’s work highlighted a research need there.

And finally, uh, before, before I wrap up

[Photo: Yellow warbler with a geolocator on its back being held by a person wearing a Cornell sweatshirt]

I’d like to, to share some, some research news that’s just now breaking. Uh this is the first public audience to get these results, and these results are from Max Witynski. 

Uh Max studied yellow warblers in Maine and in Wisconsin. He put those little devices on their backs, it’s called a geolocator, they wear it like a backpack. And that device records where the bird is. 

We put these transmitters on birds uh on the breeding grounds, they wear that for the entire year. They go to a wintering location, come back. The goal is to catch the bird again, take the device off, download the data, and find out about where they’ve been. 

And here’s a little preview.

[Photo: Max holding a yellow warbler]

This is a young Max Witynski


Uh summer of what, uh this probably what May of 2015. Uh talking about his work. 

[Video begins:

[Max] All right. I’m Max Witynski. I’ve been attaching geolocators to yellow warblers here on Appledore Island. Uh they’re like this, the light stock records ambient light levels over the course of the year, and this bird next year we can use that data to figure out where he spent the winter. So it’s pretty exciting. 

Video ends]

[David] And we did recover that bird.

[Photo: Yellow warbler being held in front of a data sheet tracking its capture and measurements, with its geolocator removed and also on the data sheet]

And six others that wore the, the backpacks for the entire year. And we were able to, to see where they went.

And Max is gonna come back up right now and do the big reveal of where yellow warblers spend the winter, okay. All right.

And I will [microphone noises].

[Max] Um, I guess before I change the slide, is anyone familiar with the winter range of the yellow warbler and have a guess where the birds from Maine verse the birds from Wisconsin that we tagged spent the winter?

Pretty close.

[David] Good guess. Any other guesses?   

[Max] Awesome. In between those two locations. Um, so this is a map.

[Image: Map of contiguous US, Mexico, Central America, and northern South America with lines depicting the migration of seven yellow warblers from Wisconsin to Venezuela and Maine to Colombia]

Um, so we had two breeding populations that we tagged birds from. One near my home in Wisconsin uh which is the blue dot, and one in Appledore Island in Maine which is the red dot, uh up in the United States.

And so we recovered four birds from Maine and three birds from Wisconsin. And the most interesting takeaway I think from this map is that you can see that the birds from Wisconsin actually spent the winter in Venezuela, east of the birds from Maine, which wintered mostly in Colombia.

So the longitudinal segregation on the wintering grounds doesn’t match that on the breeding grounds. Um which is pretty interesting, it’s, it shows just how much we have to learn about where songbirds from our backyards spend the winter and whether or not that correlates to where they spend the summer.

So all of those migration paths are more than 3000 miles long. Unfortunately we only have the data for fall migration um because the battery life of the device is only nine months. But it’s still really interesting and really exciting. So I’m working on putting that thesis together now.

Thank you guys.

[Microphone noise]

[David] He better be working on that thesis now. So all right, so that was the, the world premiere or yellow warbler migratory connectivity. Thanks, Max. 

And uh, so those are just a,

[Photo: Sunrise over the ocean from Appledore Island]

a few of the stories of the uh impressive research that the undergrads can accomplish when they’re sort of set free to, to explore, to, to ask questions. Uh and to study in a pretty remarkable place like the Isles of Shoals. 

To conclude I’d like to allow each of you to sort of experience what’s it’s like uh to be an intern uh at the Isles of Shoals.

Uh this is a film that was directed and edited and put together by Sarah MacLean who you met at the, at the beginning of the talk, and this is called A Day in the Life.

[Video begins: Cheerful music plays

Sunrise over Appledore Island]

[David] I did not pick the music]

[Video continues: A bird flies by and calls in front of the rising sun.

Video text: 5:00 am: Sunrise

Group of common eiders in the water.

Tree swallow on a wooden fence preening and singing.

Yellow warbler in a tree singing.

Video text: 5:30 am: Gull nest checks

Woman walking into gull nesting area wearing a bike helmet with gulls flying around her and calling.

Four people walking along the rocks to check gull nests.

Great black-backed gull with beak open on a nest.

Gull egg hatching in a person’s hand.

Woman using green marker to write on the egg.

Gull chick held in a person’s lap.

Gull calling while standing on a rock.]

[David] This was my editing mistake right here. Uh this was not part of Sarah’s original movie, but I like M35 as, he’s a nice gull.

[Photo: Gull tagged M35 standing on a rock and calling]


[Video continues:

Video text: 9:30 am: Check Black Guillemot nest

Person talking about looking for guillemot nest as camera moves through rock crevices.

Guillemot nest with egg and chick in covered rocky area.

Black guillemot adult in rocky area.]

[David] These are the southernmost-nesting black guillemots on the planet.

[Video continues:

Video text: 10:30 am: Break to appreciate the scenery

Camera pans to show ocean and rocky shore.

Person walking on the rocks and birds flying over the ocean.

Person sitting on rocks looking out over the ocean.

Terns flying through the sky.

Video text: 11:30 am: Check banding station for cool birds

Person banding a warbler and taking measurements.

Gray catbird being handed off between two people as it calls.]

[David] Gray catbird. Black-billed cuckoo.

[Video continues: 

Person holding a black-billed cuckoo with other people standing nearby.

Video text: 12:30 pm: Discuss adorable chicks

David and Michelle sitting in the cafeteria looking at David’s phone, talking, pointing, and smiling.

Video text: 1:30 pm: Independent projects

Michelle in the pop-up tent with David, a computer, and equipment.

[Sarah] Best behavior.

[Michelle] Hello, we could use some masking tape. Wait, you need to see, can you see the whole setup in here? We have chairs now.

Shailee holding a tripod.

[Shailee] If any of you say this is not the right way to carry a tripod…

Shailee walks off with the tripod, microphone, and backpack while wearing a bike helmet.]

[David] Shailee with her sound recording equipment.

[Video continues: Great black-backed gull settling onto nest.

Computer screen with graph, then camera pans to two gull eggs in a plastic container and one held by Michelle, sitting next to David.

[Michelle] And there’s this huge spike in ultraviolet light which we can’t see but the birds can see. So it might have some sort of really cool effect on the way birds see this egg, and maybe on how this egg survives [inaudible]. It’s just really exciting to see because it’s so rare. Ah! Oh my gosh. Look how, it’s so cool! I’m gonna freak out this is so cool.

Gulls flying above woman on the rocks.

Video text: 4:00 pm: Assist intertidal interns

Woman standing in tide pool and touching something, then standing up and laughing.

Michelle holding a lobster with another woman standing nearby.

Woman holding a lobster.

[Sarah] Yeah, he did that when he was out of the water and I dropped him. But I got him back.

Woman holding the lobster laughs.

Gull in shallow water.

Video text: 8:30 pm: Sunset

Shailee walking in a grassy area with gulls nearby as the sun sets.

Photo: Gull chick held up with rocks and ocean in the background

Video text: SHOALS Marine Laboratory

Video: Sarah MacLean

Music: SaReGaMa


Music fades

Video text: www.sml.cornell.edu

Video ends]

[David] All right, so I’d just like to, to end by

[Slide text: Special thanks to the inspirational students, past and present, who have tolerated me as a research mentor.

Thanks to:

Cornell Lab of Ornithology Redhead Fund for Undergraduate Research

Jean and Betty Rowley

Rawlings Cornell Presidential Research Scholar program

Biology Scholars Program

Morley Undergraduate Research Fund

Office of Undergraduate Biology

Dr. Julie Ellis, Dr. Irby Lovette, William Clark, Dr. Cassie Stoddard, Dr. Sara Morris, Tracy Holmes, The Staff of Shoals Marine Lab

Photos: Shailee Shah, Sarah MacLean, Jim Coyer, Facundo Fernandez-Duque, Liam Berigan; Photo: Silhouettes of gulls against a red and orange sky]

thanking a whole lot of folks. Uh, the Redhead Fund for Undergraduate Research here at the Lab has, has helped support a lot of this, Jean and Betty, thank you. They’re, they’re embarrassed back there, but that you for your support. Uh lots of different programs at Cornell that support undergrad research. I’m incredibly envious of the opportunities that these students have. Uh, and then a lot of my colleagues who, who help out at the Isles of Shoals. Um so thanks to them, and most of all thanks to the, the students who have uh made me want to get up and out in the field at 4 o’clock every morning. So. 

And I’d be happy to answer any questions. So.

Yeah? Go ahead, yeah. 

[Audience question]

[David] Okay, so I think I have to repeat the question for the people on the, on the web. Repeat question sign. Thank you, Mary. Uh so the, the question is what sort of recovery rate did we have for the yellow warblers that were, were wearing the geolocators. 

We put out 20 and got back seven of the devices, which is, uh in a normal year you’d expect only about a 50 percent adult survival rate. So best case scenario we would have thought we’d get ten back, and we got seven back. So um, so that was pretty good. 

Uh there are rules about how much weight you can put on a bird. You can only put on less than five percent of the bird’s body weight. And these devices are, are so small and so light now that they’re less, they weigh less than five percent of a yellow warbler, which is about. So they weigh about point, point four?

[Max] A little less than that.

[David] A little less than point four grams, those little geolocators.


[Audience question]

[David] All of my students have done original research. And the reason is, it’s becoming increasingly difficult to get replicated studies published. Um if it’s not new, and it’s not novel, uh journals don’t care. Uh so these students, you know it’s changed so much since, since I was in grad school.

Oh, Jean, I was supposed to repeat the question.


What uh, what uh, the question is uh how many of the studies are replicated studies, uh and how many are new and original research? They’re pretty much all new.  

When I was in grad school, or when I was applying for grad school you could just send in an application like you do for undergrad, and get accepted. 

Uh these days, so many students want to stay and, and get advanced degrees it’s really hard to get into grad school. And so the students are highly motivated to get publications, to get peer-reviewed scientific publications out from undergrad. It wasn’t even on my radar when I was a student, when I was an undergrad student.

Uh, but these, these kids now are putting out you know two, three papers from undergrad, which is a ticket to grad school. So they really want to do original research that allows them to, to get into grad school.

Uh, I think we have a, a question from the web.

It better not be my mom.


[Lisa reads question]

[David] Oh, that’s a good, yeah, good question. Um, I can only, of the students I’ve worked really closely with who’ve done senior theses with me, uh only two of them went sort of outside of the biology realm. Um, but I think that’s a little unusual. Um, their, the job, what I tell all students now, get a computer programming degree. Uh because people will be throwing money at you, uh so.

Any, another question?

Take one.

[Audience question]

[David] Ah, the question is how much do the geolocators, those little transmitters on the yellow warblers, how much do they cost? And I believe, they were in British pounds, so it depends on the exchange rate, but I believe it was something around 250 dollars each. So. Yeah. To get, to get electronics that small it, it costs.


[Audience question]

[David] Uh the question in how the fire ants, those invasive ants that are attaching the gull chicks, how they reached uh the, the island. Uh actually those, those ants, they’re European in origin and so shipping brought them to coastal New England. They’re now all up and down the coast. 

They haven’t moved inland very far, but a lot of beaches have problems with you know, people being bitten by ants as they’re lay out uh in the sun. 

Um so, I don’t know that we actually know how they originally came to North America, but it was people. People did it.

[Audience question]

[David] Oh, there are boats going out there every day, you know, there are logs floating up onshore. Um, muskrats swim from the mainland, so it’s not that far. 

[Audience question]

[David] They’re muskrats out there, and um people have put raccoons out there in the past, um to, to get rid of the gulls. Uh which was not a good thing. Um but yeah, it’s not that far from the mainland but it, it often feels like a completely different world uh when the fog rolls in and you can’t see the mainland, and it’s yeah, it’s a surreal experience out there.

Lisa you had another question from online?

[Lisa reads question]

[David] So, yeah, so, so these birds can live to be quite old, and if both the male and the female is alive more often than not they stick together. And, and uh will mate together often in the same scrape on the ground year after year after year. So we, we have a number of gulls that we know, known pairs uh that are really, you know they’re island heroes. Uh there’s the Herringtons, a pair of herring gulls,


which uh the students love every year. So sort of these gulls that are in known locations. Um, what we do know about how, about the success of pairing is we know um that young males are stupid, and not good parents.

Uh so if a female pairs with a young male who, who, it’s his first reproductive attempt it almost always fails. They have to try a couple of times before they, before they figure it out. 

The issue is that we have a female-biased adult population. There are a lot more females out there than males. We don’t know why yet, it’s something we’ve been try to, trying to figure out. So there are a lot of sort of desperate females who are willing to mate with anything. 

They have mated with other species, and they often mate with immature males. So these are, these are males that are kind of hanging out on the island that are not serious about reproducing, but the females try it anyway. And it almost always fails. So, uh I would guess that the pairs that are together for long periods of time end up being quite successful. 

Um, if they fail a couple of years in a row we also know that there’s divorce. So if they try with one mate a couple of times, it doesn’t work, they’ll, they’ll split up and find somebody else.

[Audience question]

[David] Yeah we put green tags on the herring gulls and black on the black-backed gulls. Uh, and, and it’s a coordinated system all up and down the Atlantic seaboard. Uh one of my, my collaborators and grad school buddies Noah Perlut is uh studying gulls in Portland, Maine and I think he uses orange tags. So the color helps identify the, the nesting colony. Um and uh, yeah you only have three digits so we, we use colors and combinations of digits to make everything unique.


[Audience question]

[David] The, the question is how many students participate in this program, and how many of those write a senior thesis? Um, I, uh, I’ve, how many in the lab group now, Max? It’s like 20? Yeah I’ve got about 20 students in my lab group right now. Uh I’ve had, for the last ten years I’ve had two, two or three interns on the island per year. Um, pretty much all of them do senior theses because that’s sort of the goal, so yeah.

[Audience question]

[David] Mmhmm. 

[Audience question]

[David] Yeah, the question is about nesting site fidelity in birds other than gulls on the islands, and yeah, all of these birds are remarkably faithful to their breeding areas. 

In fact the yellow warblers, we only put uh the transmitters on male yellow warblers. And, I, I knew where we caught them last year. And so I’d go out and find these males singing in the exact same bush where we caught them last year. You know they’re going to Venezuela, they’re going to Colombia, and they’re coming back to the exact same spot. 

Uh the barn swallows will reuse nests year after year, uh which is, can be a problem because that’s when the mite loads build up. But it’s sort of balance, right, because when you build a new nest it takes time and energy and it delays your reproduction. So that’s bad, but a new nest doesn’t have mites. You can reuse an old nest that has mites, it’s a, you know, it’s a trade off.

But all of these birds have a remarkable level of fidelity to their nesting areas. 

All right. One more.

[Audience question]

[David] Yeah the, the question is whether or not the, the birds on the island use, use the ants in what’s know as anting to keep parasites and such off their feathers. 

Uh I’ve actually not seen that on Appledore, I, having been bitten by the fire ants many times I would not recommend that to the birds. Um, one thing we do, do see on, on the island is um, we think it’s because, and you know the, the ant people will tell you it’s because these are introduced ants. And they form super colonies in the introduced area, so huge, huge numbers, much higher than they would be back in their old Europe.

Because they’re so genetically similar to one another the different colonies don’t recognize the neighbors as sort of the enemies. And typically ant colonies sort of keep each other in check, they’re battling over territory. Uh but on Appledore all of these ants are genetically identical because they’re introduced, and it’s just one super colony. So we get incredible numbers of ants out there. It’s uh, yeah, it’s not fun.


All right, well thank you everybody for coming out.


Thank you, Max.

[Student] So, uh thank you for your lecture. 

[David] Uh-huh.

[Student] So I’m from the Cornell Sun, 

[David] Oh, great.

[Student] and I’m just recording your lecture because I want to cover it.

End of transcript

The Isles of Shoals are an ideal place to immerse students in learning and research focused on birds. For the past decade, Dr. David Bonter has taught Field Ornithology on this craggy archipelago in the Gulf of Maine, mentoring Cornell undergraduate students studying the eiders, swallows, gulls and warblers that invade the islands during the breeding season. In this Monday Night Seminar, Dr. Bonter virtually transports us to Appledore Island and recounts some of the students’ discoveries, and the trials and tribulations of ornithological field work.