NATURAL SCIENCES OF PHILADELPHIA. 97 



Cab.; Vii^eo olivaceiis, Y'le'iL ] V. novahoracensis, Bonap; Cyano- 

 spiza cyanea, Baird ; and 3Ielospiza melodia, Baird. Why the 

 small birds should be the recipients of such unsolicited favors it 

 would be difficult to guess, -unless the cowardly spirit of the 

 species under consideration operates to prevent similar discour- 

 tesies being shown where they would probably be resented. As 

 a proof of said cowardice, might be cited the stealthy manner in 

 which the female approaches the nest of any of the above species. 

 She is ev^r on the alert for fear of detection by the rightful 

 owners. In case of discovery she takes to flight, sometimes fail- 

 ing to complete her work ; but when suddenly pressed, she is 

 compelled to drop her egg. This will account for the eggs which 

 are occasionally seen either entire or broken upon the ground. 

 It is said that the egg of the cow-bird hatches rather sooner than 

 those of the birds among which it is found, and from this it is 

 argued by some, that it is a wise provision of nature, which, 

 were it otherwise ordered, would defeat the end she had in view. 

 The writer knows from experience that sometimes a nest of eggs 

 is a longer time in hatching than at others; the difference of time 

 being the evident result of variation in the amount of heat to 

 which they are subjected. Now, the egg of the cow-bird being 

 perceptibly larger than the others, would receive more heat from 

 the body of the female than the latter's own, for the simple reason 

 that it is in closer proximity to the source of heat. This seems to 

 be a satisfactor}^ explanation of its much shorter period of incuba- 

 tion. Were the eggs hatched by their rightful author, there is no 

 doubt that the time would vary but a trifle, if any, from that of 

 the rust}' black-bird. 



Agelaieus phoeniceus, Vieil. 



At the time of writing, March 24th, not a single individual of 

 this species is to be seen, while the purple grakle is found in pro- 

 digious numbers. About the first of April is the usual time of its 

 appearance witli us. Like the crow-black-bird, it is fond of society, 

 many pairs being observed building within a few paces of each 

 other in the same swamp or meadow. Occasionally a nest is 

 constructed within a tussock of grass, but generally upon the 

 alder bushes so common along the borders of meadow streams, 

 where the eggs and young are less liable to the attacks of snakes, 

 particularly Bascanion constrictor and Tropidonotus sipedo7i which 

 seem to have such a decided penchant for such fare. 



