ICTERID.E — THE ORIOLES. 155 



of chai-acters for two races. The extremes of size in this species are as 

 follows : — 



Largest. (11,271, $, Fort Briclger.) Wing, 4.G0 ; tail, 3.35; ciilraen, .72; tarsus, 1.03. 

 SmaZtei. (17,297, (?, Mira Flores, L. C.) '^ 3.80; " 2.65; " .GO; " .84. 



Habits. The common Cow Blackliird has a very extended distribution 

 from the Atlantic to Calilbruia, and from Texas to Canada, and probably to 

 regions still farther north. They have not lieen traced to the Pacific coast, 

 though abundant on that of the Atlantic. Dr. Cooper thinks that a few 

 winter in the Colorado Valley, and probably also in tlie San Joaquin Valley. 



This species is at all times gregarious and polygamous, never mating, and 

 never exhibiting any signs of either conjugal or parental affections. Like 

 the Cuckoos of Europe, our Cow Blackbird never constructs a nest of her 

 own, and never hatches out or attempts to rear lier own offspiring, but im- 

 poses her eggs upon other birds ; and most of these, either unconscious of tlie 

 imposition or unable to rid themselves of the alien, sit upon and hatcli the 

 stranger, and in so doing virtually destroj' tlieir own offspring, — for the 

 eggs of the Cowbird are the first hatched, usually two days before the others. 

 The nursling is much larger in size, filling up a large portion of the nest, 

 and is insatiable in its appetite, always clamoring to be fed, and receiving 

 by far the larger share of the food brought to the nest ; its foster-companions, 

 either starved or stifled, soon die, and their dead bodies are removed, it is 

 supposed, by their parents. They are never found near the nest, as they 

 would be if the young Cow Blackbird expelled them as does the Cuckoo ; 

 indeed, Mr. Nuttall has seen parent birds removing the dead young to a 

 distance from the nest, and there dropping them. 



For the most part the Cowbird deposits her egg in the nest of a liird much 

 smaller than herself, but this is not always the case. I have known of their 

 eggs having been found in the nests of Turdvs mustelinus and T. fuscesccns, 

 Sturndla magna and ;S'. neglcda. In each instance they had been incubated. 

 How the young Cowbird generally fares when hatched in the nests of birds 

 of equal or larger size, and tlie fate of the foster-nurslings, is an interesting 

 subject for investigation. Mr. J. A. Allen saw, in Western Iowa, a female 

 Harporhynchus rufus feeding a nearly full grown Cowbird, — a very inter- 

 esting fact, and the only evidence we now have that tliese birds are reared 

 by birds of superior size. 



It lays also in the nests of the common Catbird, but the egg never remains 

 there long after the owner of the nest becomes aware of the intrusion. The 

 list of the birds in whose nests the Cow Blackbird deposits her egg and it is 

 reared is very large. The most common nurses of these foundlings in New 

 England are Spizella socialis, Evqndonax minimus, Geothlypis trichas, and all 

 our eastern Vircos, namely, oUvaceus, solifurius, novehoracensis, f/ilvus, and 

 flavifvons. Besides these, I have found their eggs in the nests of Polioptila 

 cmrulea, Mniotilta varia, Helminthophaga Tvfir.a.pilla, Dendroica virens, D. 



