120 NORTH AMERICAN WARBLERS. 



683. Icteria virens (Linn. ). Yellow-breasted Chat. 



Breeding range. — The northern and western extensions of the 

 summer range of the yellow-breasted chat closely coincide with the 

 corresponding limits of the Carolinian life zone. The breeding range 

 extends from southern New England through southern New York to 

 southern Michigan, southern Wisconsin, central Iowa, southwestern 

 Minnesota, and southern South Dakota, south through eastern 

 Nebraska and eastern Kansas to eastern Texas, and east to the Atlantic 

 coast, with a few scattering records from New Hampshire, southern 

 Ontario, and other points north of the normal limits of the species. 

 Breeding individuals from Texas show a tendency toward the western 

 subspecies, longicauda., but on the coast as far south at least as the 

 mouth of the Rio Grande they are more closely allied to the eastern 

 than to the western form. A few miles west, at Monterey, Nuevo 

 Leon, breeding birds approach more closely the western form. In 

 this whole area of several hundred thousand square miles the species 

 is common in localities suited to its habits, except in the mountains of 

 Pennsylvania and the higher parts of the AUeghenies in Virginia, 

 North Carolina, and Tennessee, i. e., above 3,000 feet. 



Winter range. — The range of the chats in winter in Mexico and the 

 dividing line at this season between the eastern and western forms 

 have been quite clearly worked out by the parties of the Biological 

 Survey. The eastern bird comes into eastern Mexico from Texas, and, 

 passing through Tamaulipas, northeast Puebla, and northern Vera 

 Cruz, winters abundantly along the coast and in the lower portions of 

 Tabasco, Campeche, and Yucatan, and less commonly back from the 

 coast to an altitude of 4,000 feet. It ranges south over the lower por- 

 tions of Chiapas to the Pacific coast, and is found sparingly in eastern 

 Oaxaca and south from Yucatan over Guatemala, chiefly in the lower 

 portions of the countrj^, but occasionally to 6,000 feet. The eastern- 

 most locality on the Atlantic side at which its occurrence is recorded 

 is southeastern Nicaragua, where it has been observed to be not uncom- 

 mon during the winter. In Costa Rica it is recorded as a not uncommon 

 fall and spring migrant at San Jose, probably wintering in the lower 

 lands along the Pacific coast. There are no records of its occurrence 

 in the West Indies nor in South America. 



The eastern form of the chat breeds in a district whose limits include 

 an area of 700,000 square miles and throughout which it is quite 

 thoroughly distributed. The outlines of its known winter range 

 include an area of 200,000 square miles. The total limits of the breed- 

 ing range of the western form include an area of 1,300,000 square 

 miles, but so much of this is mountain and plateau, where it is known 

 that chats do not occur, that the real breeding area is not over 400,000 

 square miles. The known winter home of the western form has an 

 outside area of liiO,000 square miles. 



