The Migration of North American Birds 



Compiled by Prof. W. W. Cooke, Chiefly from Data in the Biological Survey 



With a Drawing by Louis Agassiz Fuertes 



(See Frontispiece) 



THE WHITE-BREASTED NUTHATCH 



The White-breasted Nuthatch is one of the most widely distributed birds 

 in the United States, and probably more closely confined to the United States 

 than any other species which ranges from ocean to ocean. It has been separated 

 into five forms, each of which is non-migratory. The typical form (Sitta 

 caroUnensis carolinensis) occupies the United States east of the Great Plains, 

 from southern Canada to the northern part of the Gulf States. Next, to the 

 westward comes the Rocky Mountain Nuthatch {S. c. nelsoni) inhabiting the 

 entire Rocky Mountain region from southern Canada to northern Mexico. The 

 remainder of the United States west to the Pacific coast is the range of the 

 Slender-billed Nuthatch {S. c. aculeata), which also penetrates a short dis- 

 tance into southern British Columbia and into northern Lower California. 

 The Gulf coast east of Mississippi and the State of Florida constitute the home 

 of the Florida White-breasted Nuthatch {S. c. atkinsi), while the fifth form, the 

 San Lucas Nuthatch {S. c. lagunm), is restricted to the southern part of 

 Lower California. 



THE RED-BREASTED NUTHATCH 



The Red-breasted Nuthatch is the only member of the genus that is 

 decidedly migratory, but its movements are so irregular that little can be said 

 with certainty concerning its migrations. It nests at ocean level as far south 

 as Massachusetts, but in the mountains it breeds south to North Carolina, 

 and the presence of these mountain-breeding birds obscures the migratory 

 movements of the more northern breeders. But the irregularity of the winter- 

 ing is the most serious drawback to an exact statement of the average time of 

 migration in both spring and fall. While most of the birds of the eastern 

 United States winter south of latitude 41°, some remain at this season north to 

 Nova Scotia, central Ontario and northern Wisconsin, nearly to the normal 

 northern limit of the breeding range. 



In the western United States the conditions are still worse, for the species 

 breeds in the San Bernadino Mountains of California at the southern end of 

 the range, and winters north to central British Columbia, almost as far north 

 as it breeds. 



While a few individuals winter in southern Canada, and thus confuse the 

 records on spring migration, it is noticeable that, at places where the birds have 

 not wintered, spring migration dates are late. Nearly all migrants remain 

 south of latitude 41° until after the first of May, and then within the next two 

 weeks occupy the whole of their summer home. 



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