Eastern Kingbird

The pugnacious Eastern Kingbird is well known for its noisy defense of its territory and nest site. Not only do they aggressively exclude other kingbirds (males are even aggressive toward their mate at the very beginning of the breeding season), but they are often seen chasing and diving at birds as large as hawks and eagles. This behavior is primarily directed at animals seen as potential predators, and there is some evidence that more aggressive kingbirds have higher nest success. 

Kingbird nests are generally built along habitat edges or over water. Typically, they are on horizontal limbs of trees, but exceptions include broken off snags, telephone poles, and similar exposed man-made structures. They will also use old nests of other species if large enough (e.g., robins) and have even been known to usurp active oriole nests for their own use. 

Like most flycatchers, the Eastern Kingbird is an early migrant, and many have already left New Hampshire by early September. They spend the winter in the western Amazon basin and foothills of the Andes, with many birds using two separate locations: farther south in early winter and to the north later in the winter. During this time their behavior is completely different from what we see in New Hampshire. They travel in large flocks and feed primarily on fruit, only shifting to insects as they approach the breeding grounds. 

Although still common and widespread (they bred as far west as Oregon and Washington), the Eastern Kingbird is experiencing dramatic population declines. Data from the northeastern United States, including New Hampshire, indicate that there are fewer than half as many kingbirds as there were in the 1970s. Reasons for the decline aren’t well understood, but might include loss of open habitats (to agriculture, development, or forest maturation) or effects of pesticides on insect populations.