510 MIGRATIONS OF THE BLUE-HEADED GREENLET 



dently be found to brerd in the higher portions of this water- 

 shed, where it is now only known as a migrant. 



The two paragraphs just cited have already brought up the 

 next question to be considered the method of the bird's dis- 

 tribution over the area already determined to be its habitat, 

 and the periods of its dispersal. It should be noted, in the first 

 place, that, though we have no satisfactory evidence of the 

 bird's wintering anywhere in the United States, and though 

 we know it well as a winter bird of Mexico and Guatemala, it 

 still seems probable that some individuals may linger along 

 our southern border during the season in question. In fact, 

 this is virtually attested by Bach man's early notice of the 

 species in South Carolina in February, if there be no mistake 

 about this ; and Gambel has something to the same effect for 

 Southern California. But there is no doubt whatever that the 

 great body of the birds pass beyond our limits in the fall. The 

 movement begins at the north in September, and by the end 

 of the following month the birds are already, as a rule, beyond 

 our confines. The return commences at the very opening of 

 spring, and by the middle of April these Vireos have already 

 become generally dispersed, though the limits of the migra- 

 tion, as in Maine, Canada, Wisconsin, and the Columbia River 

 region, are not attained until the first or second week in May. 

 Thus, at Washington, D. C., where this Yireo is the rarest of 

 its kind, Dr. Prentiss and myself noted its arrival on the 25th 

 of April, and its departure October 20th. The Rev. Dr. 

 Turnbnll's note for Eost Pennsylvania and New Jersey is sub- 

 stantially the same. In the vicinity of Philadelphia, says 

 Gentry, it usually arrives about the 15th of April, sometimes 

 not till the beginning of May, and retires during the latter 

 part of September or early in October. In Connecticut, where, 

 according to Merriam, it is not uncommon during the migra- 

 tions, and where a few breed, the same authority fixes the 

 time of its advent as the first week in May ; but he adds, that 

 it has been seen in the fall as late as the 13th of October. 

 Various New England writers agree upon the first or second 

 week in May as the time of appearance of the bird in their 

 midst. Mcllwraith's date for Hamilton, Canada West, is May 

 10th. The records from the Western States are less explicit, 

 but agree as far as they go ; and the same may be said of the 

 still fewer data we have received from the Rocky Mountain 

 region and the Pacific coast. 



