248 BULLETIN 196, UNITED STATES NATIONAL MUSEUM 



ground. In the air they are not so expert as the flycatchers and 

 cannot catch the swifter insects, but they are often seen fluttering 

 along near the ground after low-flying insects or darting out from a 

 perch on some high tree to snap up passing insects, sometimes darting 

 about with a hovering flight for a considerable distance from their 

 perch. Francis H. Allen writes to me: "One September day I saw 

 about a dozen of them feed thus for an hour or two, the air being full 

 of dancing gnats." Once, he saw "a male feeding for a long time on 

 the ground on a lawn, progressing in straight lines for considerable dis- 

 tances. He fed much as a robin does, but hopped instead of running 

 and did not pull out worms." 



In the trees bluebirds dart about among the foliage for flying insects, 

 or pick caterpillars, katydids, and other insects from the leaves and 

 twigs. Fruits and berries must be picked mainly from the trees and 

 bushes. 



But by far the greater part of their insect food, such as grasshoppers, 

 crickets, beetles, etc., is found on or near the ground, and one often 

 sees a bluebird sitting on some low perch, a fence post or wire, or 

 some low tree, watching for its prey. Then it suddenly darts down, 

 seizes something from the ground, and returns to its perch or another 

 lookout point. Perhaps it may flutter down and, hovering just above 

 the grass tops, seize a grasshopper and alight on the ground to eat it 

 or return with it to its perch. Sometimes it stands on the ground 

 and looks around, or actively searches for beetles or crickets; if its 

 prey takes wing, the bird may flutter along after it and catch it in the 

 air. 



Behavior. — Bluebirds are generally regarded as gentle and lovable 

 birds and rightly so, for such is their ordinary demeanor. If undis- 

 turbed they are friendly with their avian neighbors. But they can 

 be aggressive, and even fierce in standing up for their rights against 

 aggressors. In the competition for nesting sites they have often 

 been known to compete successfully with English sparrows and tree 

 swallows, attacking and driving them away when they attemptsd to 

 usurp their nesting box. Other larger birds are often driven away 

 from the vicinity of the bluebirds' nest; the male stands guard while 

 the female is incubating, feeds her occasionally, and drives away 

 unwelcome intruders, even human beings. Once, while I was intro- 

 ducing a young boy to the mysteries of bird study, we were vigor- 

 ously attacked; one of our party had removed the female and was 

 holding her in his hand; and while the boy was examining the nest 

 the male flew at him so savagely that he lost his balance and fell 

 flat on his back. Mr. DuBois (MS.) had a bluebird fly at his head 

 in a very determined manner several times while he was examining a 

 nest with young; it did not actually strike him but came very near it. 



