When we think of migrating birds, we tend to think of the ones that fly south for the winter and return north in the spring.

This is the pattern for a lot of different kinds of birds because they are going where there is food. Insect-eating birds, including flycatchers, warblers, orioles, tanagers and cuckoos have to go to where the climate is warm enough for insects to be flying, while waterfowl such as cormorants, geese, loons, grebes and ducks have to move far enough south to find water that isn’t frozen.

Things are a little different for birds that eat mainly seeds and berries during the nonbreeding season, such as finches, cedar waxwings and some sparrows. Most of them aren’t bothered by cold weather as long as they have food available, but among these species there are still some that stay here year round, some that migrate moderate distances (maybe a few hundred miles) and some that move around nomadically to wherever there is a good seed crop on their favorite kind of plants — and those seeds and fruits are above the snow.

Birds that specialize in prying open hemlock, pine, fir and spruce cones and eating the nutritious seeds hidden beneath the woody do just fine up north year round until a year comes along when the trees don’t have many cones for one reason or another — possibly weather-related problems or maybe just natural cycles. If there is a cone crop failure in one part of the vast northern coniferous forests of our continent, these birds will start traveling and fly until they find a good supply of food.

When there is a shortage of seeds for food over a big area, large numbers of these birds, collectively called winter finches, head south looking for a reliable supply. This group includes pine grosbeaks, evening grosbeaks, red crossbills, white-winged crossbills, purple finches, redpolls and pine siskins. When birds spread outside their regular range like this it is called an irruption.

Pine siskins (Spinus pinus) are very closely related to American goldfinches (Spinus tristus), with which we are all familiar, but they have much different habits.

Pine siskins are sort of like RV nomads who drive around and stay for a while here or there and then move on when they get tired of a place.

Siskins will nest wherever they happen to find a good food source, which may be a hemlock forest or a bird feeder. They often come to eat sunflower chips or kernels and niger seed from bird feeders.

Siskins blend in with their goldfinch cousins at first, but you will notice they are darker brown on their backs and head and streaked with brown underneath. Males usually have yellow coloring on their wing and tail feathers, which may be visible even when folded, but females usually show little or no yellow color and need to be identified by their streaking. They are smaller than house finches, and so usually are easy to separate from the females of that species.

Siskins make it this far south in significant numbers about every three to five years, and this winter seems to be an irruption year for them. We’ve had up to 10 at a time mixed in with goldfinches at our feeders, where they squabble and push for the best perch to feed at.

It is always fun to watch them and hear their calls. They make a very distinctive rising “ZZZZEEEEE —ZZZZEEEEEE” call that is easy to remember and unlike any other bird call in our area.

Have any of you had pine siskins or any other winter finches in your yards this winter? Keep a lookout and report them to eBird.org or email me if you do. Other birders will be interested!
