undergrowth, and when a nest is dis 

 covered, patiently awaits from a con 

 venient hiding-place the temporary 

 absence of the parent, when the nest 

 is stealthily and hastily inspected, and 

 if found suitable, she takes possession 

 and deposits her egg, when she de 

 parts as quietly as she came." "In 

 the village of Farmington, Conn.," 

 says Florence A. Merriam, u we once 

 saw a song sparrow on a lawn feeding 

 a cowbird bigger than she. When she 

 handed it a worm, one of my field class 

 exclaimed in astonishment, 'I thought 

 the big bird was the mother!' ' 



Some of the foster parents abandon 

 their nests, or build a second nest over 

 the eggs, but usually the little bird 

 works faithfully to bring up the found 

 ling. Sometimes the egg is recognized 

 by the mother and quickly thrown out. 

 Frequently, also, the cowbird will eject 

 one or more eggs of theownerto make 

 room for her egg, or to deceive the 

 owner and leave the same number of 

 eggs as were in the nest before her 

 visit. Sometimes an egg of the owner 

 is found on the ground near a nest 

 containing an egg of the cowbird, and 

 it is no unusual occurrence to find an 

 egg of the cowbird lying near a nest of 

 a species regularly imposed upon by 

 the parasite. Silloway says that the 

 wood thrush, towhee, field and chip 

 ping sparrows, yellow-breasted . chat, 

 and the Maryland yellow-throat are 

 oftenest selected to bear the burden of 

 rearing the young of the cowbird. 



In their courtship the males are very 

 gallant. They arrive from the south 

 several days in advance of the females. 

 At this season about the middle of 

 March they generally associate in 

 groups of six or eight, and the males 

 are easily distinguished by the gloss 

 of their black plumage in contrast to 

 the dull brown of the female. They 

 do not pair, the females meeting the 

 advances of the malesindiscriminately. 

 Dr. Gibbs, however, thinks that the 

 birds may pair frequently for the sum 

 mer, and suggests this as reasonable, 

 referring to an incident coming under 

 his notice when he saw a blue jay, on 

 the point of despoiling the nest of a 

 vireo, driven away by a pair of cow- 

 birds in a most valiant manner. In go 



ing to the nest he found a large over 

 grown cowbird occupying the largest 

 share of the structure, "while a poor 

 little red- eyed vireo occupied a small 

 space at the bottom, and beneath his 

 big foster brother." 



The eggs of the cowbird hatch in 

 eleven or twelve days. They average 

 .88 by .65 of an inch, the length vary 

 ing from .95 to .67 of an inch, and the 

 width varying from .72 to .58 of an 

 inch. The ground is a dingy white or 

 gray, and the markings vary through 

 all the shades of brown, sometimes 

 evenly distributed over the surface, and 

 at other times predominating around 

 the larger end. There is so much divers 

 ity in the appearance of different speci 

 mens, that frequently the investigator 

 is puzzled in distinguishing the true 

 eggs of the towhee, cardinal, and other 

 species from those of the cowbird. 



In the breeding season the male 

 grackles, red-winged blackbirds, and 

 the cowbirds of both sexes, nightly 

 congregate to roost together. Early 

 after the breeding season they form 

 into flocks of from fifty to sixty. The 

 birds have then finished moulting, and 

 the glossy black of the males has been 

 changed into the duller colors of the 

 females and the young. They assem 

 ble with the blackbirds of various 

 species where food is most abundant 

 and easy to be procured. 



Late investigations of the food hab 

 its of the cowbird indicate that the spe 

 cies is largely beneficial. Prof. Beal 

 showed the food of the cowbird to con 

 sist of animal and vegetable matter in 

 the proportion of about twenty-eight 

 per cent, of the latter. Spiders and 

 harmful insects compose almost exclu 

 sively the animal food, while weed 

 seeds, waste grain, and a few miscel 

 laneous articles make up the vegetable 

 food. Mr. Silloway thinks "it is not 

 improbable that the so-called insectiv* 

 orous birds displaced by the cowbird 

 are thus kept in check by this natural 

 agent, and their mission performed by 

 the usurper in directions as helpful as 

 the special functions of the sufferers. 

 We may later come to understand that 

 one cowbird is worth two bobolinks 

 after all." 



227 



