14 



THE SEMI-ANNUAL. 



EGGS IN SET. 

 Largest. Smallest. Av. 



i 



MKASURKMENTS. 

 Largest Smallest. Average. 



.68x1.05 .68x.6o .64X.72 







4 







,t>9x.9» 



.=; 



2 



4 









5 



3 



4 



.79X.96 



.65X.84 



.68X.90 



5 



3 



4 



.71X.96 



.62X.8S 



.'67X.88 



Berwyn, Pa., 

 Columbia, Pa., 

 Perrineville, N. J., 

 Pittsburgh, Pa., 

 Wauwatosa, Wis., 

 Grinnell, Iowa., 



In form, eggs of Catbird range from elliptical ovate, tlirough 

 ovate to pyriform ; the last form is rare. The variation in size 

 and shape is ver\' marked. 



COLORATION. 



The reports show a remarkable agreement in giving the color 

 of eggs. The universal report is, "A uniform bluish-green, fre- 

 quently fading to a greenish-blue." In notes on a large series of 

 sets I have described them as a uniform dark nile-blue. Fresh 

 eggs usuall have a limy deposit tending to appear in streaks ; this 

 is easily w'ashed off. 



PERIOD OF INCUBATION, ETC. 

 Berwyn, Pa, Lays eacli da}'. 14 days hatching. Young left in 12 days 

 Perrineville, N. J. " " " 12 to 13 " " " " " " " 



Grinnell, Iowa. " " 14 " " " " " 14 " 



We have learned that the Catbird is a seclusive bird, pre- 

 ferring underbrush and thickets to places near human habitations. 

 That he places his nest about 3 or 4 feet from the ground, build- 

 ing it into the twigs and stems of the bush or tree, or rarely 

 piling his brush into the forks. That he prefers to be where he 

 can easily and quickly *•' wet his whistle and awake the woodland 

 echoes." We might have said, too, that he is a sturdy warrior 

 when his home is assailed by squirrel, or mouse, or snake, or 

 man. Very rarely is he imposed upon by any parasite; Mr. 

 Burns being the only one who reports such a thing ; he found an 

 egg of Cardinal in one nest. 



