EASTERN HOUSE WREN 139 



The wintering area of the eastern house wren is limited on the north by low 

 night temperatures combined with long daily periods of darkness, short day- 

 light periods, low intensity of solar radiation, snow, and lack of available food. 

 On the east, the wintering area is limited by the Atlantic Ocean, on the south 

 by the Gulf of Mexico, and on the west by much the same conditions, perhaps, 

 that are effective during the breeding season. 



The southward migration of the eastern house wren in the autumn is necessary 

 for the continued existence of the species, while the northward migration in 

 the spring avoids unfavorable breeding and existing conditions in the south. 

 By migrating south in the autumn and north in the spring, the bird maintains 

 itself in a more nearly uniform and favorable environment throughout the year. 

 The regulation of migration as to time is controlled in the spring by rising daily 

 maximum and night temperatures and changing relative proportions daily of 

 light and darkness. In the autumn, decreasing temperatures particularly at 

 night, longer nights and shorter days, and, for some species, decreasing food 

 supply are most important. 



DISTRIBUTIOlSr 



Range. — Southern Canada to southern Mexico. 



Breeding range. — The house wren breeds north to southern British 

 Columbia (southern half of Vancouver Island, Chilliwack, and 150- 

 mile House) ; northern Alberta (Vermilion, McMurray, and Lesser 

 Slave Lake) ; southern Manitoba (Duck Mountain and Lake St. 

 Martin) ; central Ontario (Lake Abitibi) ; southern Quebec (Quebec) ; 

 and New Brunswick (Fredericton and Grand Falls). East to New 

 Brunswick (Fredericton) ; casually to Nova Scotia (Wolfville) ; and 

 south through the Atlantic Coast States to North Carolina (Beaufort 

 and Salisbury) and western South Carolina (Greenwood). South 

 to South Carolina (Greenwood) ; Kentucky (Harlan) ; northern Okla- 

 homa (Tulsa and Enid) ; southern New Mexico (Cloudcroft and Silver 

 City) ; Arizona (Tombstone and the Huachuca Mountains) ; and 

 northwestern Baja California (Sierra San Pedro Martir). West to 

 northwestern Baja Balifornia (Sierra San Pedro Martir) ; western 

 California (Santa Barbara, Palo Alto, and Berkeley) ; Oregon (Pine- 

 hurst, Elkton, and Portland) ; Washington (Vancouver, Shelton, and 

 Bellingham) ; and British Columbia (Courtenay). It may breed 

 rarely in the uplands of Mexico, as specimens have been taken in the 

 breeding season, but as yet no nests or young have been reported. 



Winter range. — The house wren in winter is found north to southern 

 California (Los Angeles, San Bernardino, occasionally to central Cali- 

 fornia) ; southern Arizona (Tucson) ; northeastern Texas (Bonham 

 and Corsicana) ; southern Louisiana (Jennings and Port Allen) ; Ala- 

 bama ( Autauga ville) ; and the coast of South Carolina (Cape 

 Komain) . East to South Carolina (Charleston and Port Royal) ; and 

 Florida (Daytona and Miami). South to Florida (Miami and Long 

 Pine Key) ; along the Gulf coast to southern Mexico, Veracruz (Tres 

 Zapotes) ; Oaxaca (Huajuapam) ; and Guerrero (Chilpancingo). 



