244 Habit and Instinct. 



Although the American cuckoo, a bird closely allied to 

 our European species, does not appear to be parasitic 

 in its habits ; there is a group of birds belonging to a 

 quite different family, that of the Icteridce, which have 

 similar habits. These are the cowbirds, concerning which. 

 Major Charles Bendire has collected all the available infor- 

 mation in the "Report of the United States National 

 Museum for 1893."* From his account the following 

 resume of the facts is derived. 



Like our cuckoo, the cowbirds are polyandrous, the 

 males generally outnumbering the females in the pro- 

 portion of about three to one. The common cowbird of 

 North America (Moluthrus ater) lays from eight to twelve 

 eggs in a season, probably at intervals of several days. 

 There is a large amount of variation in the size and 

 markings of the eggs ; but how far they assimilate with 

 those among which they are laid we are not told. Major 

 Bendire gives a list of no less than eighty-nine species in 

 the nests of which the eggs of this cowbird have been 

 found, sometimes four or five in one nest. It is not 

 unusual to find some of the eggs of the species imposed 

 upon thrown out of the nest to make room for those of the 

 parasite, nor to find minute punctures in the shells of 

 some of the remaining eggs. This is possibly done on 

 purpose by the cowbird with her beak to prevent the eggs 

 from hatching; but Major Bendire is inclined to attribute 

 this puncturing to the sharp claws of the parent bird while 

 sitting on the nest and depositing her own egg; for the 

 parasitical bird seems to lay in the nest and not to carry 

 the egg there in her bill. Hatching is usually accomplished 

 in from ten to eleven days, generally in advance of those of 

 the foster parent, and the growth of the young interloper 

 is remarkably rapid. At the end of a few days the rightful 

 * Pages 587-624. 



