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The Chestnut-sided Warbler 
waving aloft and almost completely hiding the feeble little mouth of the 
Warbler, whose owner was pathetically doing his best in a dumb appeal 
for food. The Cowbird's appetite seemed never to be satiated and, unlike 
most nestlings, which relapse after a meal and give their brethren the next 
chance, he seemed ready for every fresh opportunity ; and by reason of his 
superior display he usually succeeded in obtaining the coveted morsel. 
The Lion’ However, the young Warbler did manage to get an 
Share ^ occasional portion, and I had strong hopes that he 
might reach maturity, for I realized that a Chestnut- 
sided Warbler’s usual laying is about five eggs, and that therefore some 
four eggs must have been made to give place to the two Cowbirds. 
Hence the young Cowbird in the nest might reasonably be granted the 
room and food of four young Warblers. More than this I hoped he was 
not getting. 
“On July 18 at 3:30 P. M. when the birds were about four days old I 
took them from the nest to compare their sizes. I replaced them in the 
nest but that was the last I saw of the poor little Warbler. When I re- 
turned at 5 P. M. the Cowbird was in sole and triumphant possession of 
the nest. Just what became of the Chestnut-sided Warbler will never be 
known, but my theory is that, weakened by lack of sufficient food, the 
little fellow at last became too feeble to raise himself at all, and was 
crushed to death by the Cowbird’s gross body. 
“The Cowbird now had things all his own way, and, 
Success there being no one to dispute his right to all the food, 
he grew with amazing rapidity. The dainty little 
cup of a nest, never built to accommodate such a monster, was soon com- 
pletely forced out of shape. His body then protruded beyond the lower 
rim of the nest, and the ground underneath became littered with drop- 
pings quite baffling the cleanly, sanitary instincts of the Warblers. 
“The Cowbird, now almost twice as large as his devoted foster parents, 
rises with hideous chitterings of delight to receive an ever-acceptable meal. 
I visited the nest at 7 :30 A. M. on July 26. As I walked home to break- 
fast, I resolved that in the interests of justice I ought to put an end to 
that Cowbird as a murderer and a menace to the welfare of birddom. 
But when I returned to the spot, about 9 A. M., he had escaped me ; the 
nest was empty, my bird flown.” 
Classification and Distribution 
The Chestnut-sided Warbler belongs to the Order Passeres, Family Mniotil- 
tidce and Genus Dendroica. Its scientific name is Dendroica pennsylvanica. It 
lives and breeds in summer throughout the northern United States and southern 
Canada as far west as the edge of the Plains. It winters in Central America. 
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