An Opportunity Interrupted 



297 



about the outer twigs. It was a cobweb and he had begun to build his nest. I 

 watched him while he sang at his work, every now and then returning with 

 a fresh supply of cobwebs. For some time I did not see the quiet female as 

 she sat on a higher branch, and then only because of some slight attention 

 on the part of the male. She did not seem at all concerned with the home- 

 building, and showed no signs of helping with the work. 



A rather conspicuous place had been chosen for the nest, scarcely seven 

 feet from the ground, and not more than fifteen from a much-traversed path. 

 Fearing that I might attract too much attention to it, I moved on, and did 

 not go near the place again for four days, when I examined the nest from a 

 little distance with glasses. On the outside it now seemed quite complete, but 

 as yet contained very little interior decoration. The outer basket was com- 

 posed almost entirely of cobwebs, with small squares of white paper dropped 

 by some careless school-boy. 

 There seemed to be a much 

 higher percentage of cobwebs 

 than is found in the nests of 

 the other species of Vireos. 



Three days later, a week 

 after the starting of the nest, I 

 found it complete and contain- 

 ing one egg, that of a Cowbird. 

 I was in doubt as to what to 

 do. The Vireo had seen the egg, 

 I had found him on the edge of 

 the nest inspecting it when I 

 arrived. Did he think it one of 

 their own, and would he desert 

 if I should remove it, as do 

 many birds when the first egg 

 laid is stolen? Or, did he recog- 

 nize it as a Cowbird's, and 

 would he desert, as do some 

 birds, because the Cowbird had 

 laid its egg first? With most 

 birds, the attachment for the 

 nest, before the first egg is laid, 

 is a rather uncertain quantity 

 and not to be depended upon. Birds like the Redwing which show the great- 

 est attachment for the nesting site, nesting time, and again in the same bush 

 or small area of swamp land as each nest is destroyed, very readily desert if 

 the nest is merely discovered before the laying of the first egg. I, therefore, 

 debated long and seriously whether I should remove the Cowbird's egg from 



"A FALSE BOTTOM BUILT IN OVER THE 

 COWBIRD'S EGG" 



