Avian clutch size of increasing clutch size with increasing latitude. The proximate and ultimate causes for this pattern have been a subject of intense debate involving the ideas of group and individual selection. David Lack observed a direct relationship between latitude and avian clutch size. Birds near the equator laid approximately half as many eggs as those that resided in northern temperate habitats. He observed an increasing clutch-size from the equator towards the poles (something he referred to as the “latitude trend”) for many passerine (perching) birds, near-passerine (tree-dwelling) birds and in various other groups: Strigiformes, Falconiformes, Ciconiiformes, Laridae, Ralliformes, Galliformes, Podicipedifomes, and
Hawking (birds) Hawking (birds) Hawking is a feeding strategy in birds involving catching flying insects in the air. The term usually refers to a technique of sallying out from a perch to snatch an insect and then returning to the same or a different perch. This technique is called “flycatching” and some birds known for it are several families of “flycatchers”: Old World flycatchers, monarch flycatchers, and tyrant flycatchers. Other birds, such as swifts, swallows, and nightjars, also take insects on the wing in continuous aerial feeding. The term “hawking” comes from the similarity of this behavior to the way hawks take