1913] 
Cahn: Birds of Waukesha County 
121 
porting the birds, a flock of eight was seen on Pewaukee Lake, 
where it remained for several hours. Flocks have also been re- 
ported from Nagawicka and Okauchee Lakes. 
Botaurus lentiginosus (Montagu). Bittern 
A common summer resident about the less frequented and wilder 
lakes and marsh-lined river courses. A deserted nest was found 
on June 23, 1913, in the tall grass about Wash Tub Lake, and the 
adult birds with three young were flushed within one hundred 
feet of the nest. 
Ixobrychus exilis (Gmelin). Least Bittern 
A common summer resident in all suitable locations. Small 
and retiring, they are but little in evidence. Four nests were 
found at Wash Tub Lake, June 23, 1913, three containing five 
very young birds, and one three eggs well advanced in incubation. 7 
Far more common than present records would tend to indicate. 
Ardea herodias herodias Linnaeus. Great Blue Heron 
A regular spring and fall migrant and rarely a summer resident. 
A single pair attempted to nest in a swamp east of Oconomowoc 
early in the summer of 1909, but thanks to a party of small boys, 
the egg-laying was never completed, and one of the birds was killed. 
This is, so far as is known, the only recent attempt at breeding 
within the county. 
Butorides virescens virescens (Linnaeus). Green Heron 
A common summer resident, found throughout the county, 
along the water courses. Nests sparingly in suitable places, as 
the woody shores of Dutchman’s, Nagawicka and Golden Lakes. 
Feeds largely on frogs, for which it will travel long distances to 
marshes. 
Nycticorax nycticorax naevius (Boddaert). Black-Crowned 
Night Heron 
An occasional summer resident, though but rarely seen. Two 
young were seen in the swamp of the Oconomowoc River, and one 
of these was secured. This was on August 8, 1912, and an adult 
was seen in the same location on September 12, 1913. No doubt 
breeds within the county, but there is no herony, and no nests 
are recorded. 
7 Kumlien and Hollister, Birds of Wisconsin , p. 34. 
