BIRDS IN RELATION TO THE ALFALFA WEEVIL. 41 
No rough-wings were collected in August, but in all probability 
these birds continue to prey on the insect during late summer when- 
ever a flight takes place. 
The rough-wing probably is as effective an enemy of the weevil as 
the cliff swallow, but, like the latter, its work is limited to warm, fair 
days of spring and late summer. In addition to the good work of 
this bird upon this insect its economic status, based on other activities, 
is in its favor. 
YELLOW WARBLER. 
(Dendroica (Estiva (Estiva.) 
The yellow warbler is the most common of breeding warblers 
throughout the Salt Lake Valley. Whenever its favorite nesting 
site of willows along the banks of streams and irrigating ditches 
occurs about the borders of alfalfa fields, this bird is brought in con- 
tact with the weevil. 
Five birds were collected in June and two in July. Only those 
taken in the latter month were feeding on the weevil. One had eaten 
11 larvae and 1 adult, the other 6 larvae. Besides, the latter had in 
its bill 3 weevil larvae, a bug, and 9 flies. In bulk the weevil com- 
posed nearly a fourth of the food of the two. 
The other yellow warblers had fed extensively on caterpillars, 
which were found in each of the stomachs and formed nearly 
70 per cent of the food. One half -grown nestling had been fed 
exclusively on these insects. Small Hymenoptera, some of which 
were parasitic, were next in abundance, forming nearly a fifth of the 
contents. 
Although abundant about the borders of alfalfa fields, yellow war- 
blers were seldom observed dropping down to them in search of 
food. The upper branches of willows are their favorite resorts and 
apparently their food is largely secured from such places. 
MACGILLIVRAY'S WARBLER. 
(Oporomis tolmiei.) 
Listing Macgillivray's warbler as an enemy of the weevil is based 
on the examination of only one stomach. Two breeding adult weevils 
eaten in May formed about 2 per cent of the contents. There were 
also present the remains of a click beetle, a dung beetle, a flea beetle 
(Systena sp.), and a large amount of unidentified insect fragments. 
LONG-TAILED CHAT. 
(Icteria virens longicauda.) 
Our knowledge of the long-tailed chat as a weevil destroyer is 
based on the examination of three stomachs. In two the insect was 
present, one containing a mere trace of an adult, and in the other 2 
adults composed about 3 per cent of the food. 
