YELLOW-RUMP WARBLER, 357 



of our birds are subject. In the present case this change is both 

 progressive and periodical. The young birds of the first season 

 are of a brown olive above, which continues until the month 

 of February and March; about which time it gradually changes 

 into a fine slate colour, as in the figure on the plate. About the 

 middle of April this change is completed. I have shot them in 

 all their gradations of change. While in their brown olive dress, 

 the yellow on the sides of the breast and crown is scarcely ob- 

 servable, unless the feathers be parted with the hand; but that 

 on the rump is still vivid; the spots of black on the cheek are 

 then also obscured. The difference of appearance, however, is 

 so great, that we need scarcely wonder that foreigners, who 

 have no opportunity of examining the progress of these varia- 

 tions, should have concluded them to be two distinct species; 

 and designated them as in the above synonymes. 



This bird is also a passenger through Pennsylvania. Early 

 in October he arrives from the north, in his olive dress, and 

 frequents the cedar trees, devouring the berries with great 

 avidity. He remains with us three or four weeks, and is very 

 numerous wherever there are trees of the red cedar covered 

 with berries. He leaves us for the south, and spends the win- 

 ter season among the myrtle swamps of Virginia, the Carolinas 

 and Georgia. The berries of the Myrica cerifera, both the 

 large and dwarf kind, are his particular favourites. On those of 

 the latter I found him feeding, in great numbers, near the sea 

 shore, in the district of Maine, in October; and through the 

 whole of the lower parts of the Carolinas, wherever the myrtles 

 grew, these birds were numerous, skipping about with hanging 

 wings, among the bushes. In those parts of the country they 

 are generally known by the name of Myrtle-birds. Round 

 Savannah, and beyond it as far as the Alatamaha, I found him 

 equally numerous, as late as the middle of March, when his 

 change of colour had considerably progressed to the slate hue. 

 Mr. Abbot, who is well acquainted with this change, assured 

 me, that they attain this rich slate colour fully before their de- 

 parture from thence, which is about the last of March, and to 

 the tenth of April. About the middle or twentieth of the same 



