1913 ] 
Cahn: Birds of Waukesha County 
141 
found in abundance, and more often in elm trees ( Ulmus ameri- 
cana) than in others. 
Dendroica fusca (Muller). Blackburnian Warbler 
A very common migrant, arriving about the first week in May, 
returning in the fall about the third week in September. Seem- 
ingly of rather erratic occurrence, some years almost entirely 
escaping notice, and other years almost abundant. 
Dendroica Virens (Gmelin). Black-Throated Green Warbler 
One of the most abundant migrants, common after the first 
week in May until the majority of the warblers have passed on, 
and again the third week in September. During the last two 
weeks of September, 1913, these warblers were found almost 
everywhere. 
Dendroica vigorsi (Audubon). Pine Warbler 
A common migrant, especially in the spring migration, when 
it arrives very early in May, and is seldom seen after the third 
week. One of the most elusive warblers during the fall migration, 
keeping to the highest trees, and often entirely escaping notice. 
Dendroica palmarum palmarum (Gmelin). Palm Warbler 
A common migrant, and the most abundant of the early warblers. 
Found throughout the county during practically all of May, and 
again during the third week of September. 
Seiurus aurocapillus (Linnaeus). Oven-Bird 
A regular migrant, and often, though not always, apparently, 
a summer resident nesting in quiet places. Heard only in the 
spring, its presence during the summer is apt to be overlooked 
because of its quietness, combined with its retiring habits. 
Seiurus noveboracensis noveboracensis (Gmelin). Water- 
Thrush 
A regular migrant, often arriving as early as April 25, and in the 
fall individuals are reported well into October. 
Oporomis agilis (Wilson). Connecticut Warbler 
A regular though not a common migrant, found late in May 
and occasionally early in June. On September 8, 1913, four were 
seen near Gifford Station. 
