BIED MIGEATION. 39 



young of the year have been seen by the middle of July at Key West, 

 Fla., 500 miles south of the breeding range; on August 10 in Costa 

 Rica; and on AugTist 21 on the northern coast of South America. 

 These dates point to the conclusion that early migrants south of the 

 United States could not have been bu'ds from the northern part of 

 the range, but must have been those from the southern part. 



Black-throated blue warblers reach Cuba in fall just about the time 

 other migTants of the species appear in North Carolina. The infer- 

 ence is that the arrivals in Cuba are the birds that nested in the south- 

 em Alleghenies, while those appearing in North Carolina are from the 

 latitude of northern New England or beyond. Redstarts and sum- 

 mer warblers arrive on the northern coast of South America so 

 early (August 27 to September 2) as to indicate that they represent 

 the southern breeding birds. Indeed, these representatives of the 

 species are seen in South America just about the time the earliest of 

 the northern breeding birds reach Florida. 



Recent investigations have shown also that many species of birds 

 do not follow this "normal" order of migTation. The most southern- 

 bred Maryland yellow-throats are almost nonmigratory, residing 

 throughout the year in Florida; those breeding in the middle dis- 

 tricts migrate only a short distance; while those from Newfoundland 

 go to the West Indies, passing directly over the winter home of their 

 fellows in the South. The red-winged blackbirds of the middle of the 

 range in northern Texas are almost stationary, but are joined in 

 winter by migrant red-wings from the remote Mackenzie Valley. 

 Tlie palm warblers of the interior of Canada in the course of their 

 3,000-mile journey from Great Slave Lake to Cuba pass through 

 the Gulf States early in October. After the bulk have passed, the 

 palm warblers of the Northeastern Provinces come slowly to the 

 Gulf States and settle there for the winter, content with only a 

 1,500-mile trip. Some of the blackpoll warblers that pass in spring 

 through Florida proceed northeast 1,000 miles to breed in northern 

 New England, while others, traveUng northwest more than 3,000 

 miles, summer in Alaska. Among the Maryland yeUow-throats 

 nesting in western Pennsylvania are undoubtedly individuals tluit 

 (hiring the winter are scatter('d in the (lulf States, the West Indies, 

 and even Central America. These examples show that no invariable 

 rule, law, or custom exists in regard to the direction or distance of 

 migration. 



The winter (Hstrihution can not cert.ainly be d(^termined from the 

 summer home,, nor does it positively indicate that home. The 

 statement cnn be imuh still strojigc^r. Eacli species is composed of 

 many hiidiII grf)ups, eueli of whicii in r(^gard to summer and winter 

 home and route of niigration is a law unto itself, and the knowledge 

 of these facts witli regnrd 1f> oju^ group of^Ts little or no basis for 



