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 difierence 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 
