THE FRuTHOXoTARY WARBLER. 



117 



The Prothonotary Warbler is, so far as known, the only one of the family 

 to build regularly in holes in trees. We infer that it has drifted into this cus- 

 tom within zoologically recent years, since its eggs are unusually dark colored, 

 while those of all strictly hole-nesting birds are pure white. The eggs of this 

 Warbler exhibit two types of coloration, with, of course, every variety of inter- 

 mediate form. Those of the first type are heavily and rather evenly spotted 

 and dotted with dull brown, and show pale lavender shell-marks. The other 

 sort are boldly blotched with reddish brown, so heavily at times that the ground 

 color is nearly obscured. 



According to Professor Butler, the females construct the nests and per- 

 form all the duties of incubation. A few days are allowed to elapse after the 

 completion of the nest before laying begins. An egg is laid each day until the 

 set is complete, and two broods are often reared each season, especially 

 southerly. 



During the mating season the males are exceedingly irascible. One 

 hapless wight I saw. who, choosing the wrong platform for his song, was set 

 upon vigorously by a jealous rival. At the first onslaught the pair fell fighting 

 to the ground. They picked themselves up hastily, and one. probably the 

 original assailant, chased the other about for as much as three minutes. In 

 and out they wound, now coming straight toward one like golden bullets, 

 now threading the mazes of a tree-top like flashes of fire. But the fugitive 

 was plucky, too. after a fashion, and altho he thought of nothing but flight, 

 it was always within the bounds of the disputed territory. Finally the chase 

 languished somewhat, and I left the contestants, faint yet pursuing. 



Photo by C. H. M < 



