BIEDS IN KELATION" TO THE ALFALFA WEEVIL. 45 
month, when the rigors of winter have reduced the insect to its lowest 
ebb ; and any agency in the work of destruction that can be brought 
to bear at this time is of the utmost importance. The food of the 
robin in Utah speaks highly in its favor. Some complaint was heard 
that it injures cherries, but this trait does not seem sufficiently uni- 
form to offset the good it does. Until the weevil is reduced in num- 
bers the services of the robin as a destroj^er of breeding adults alone 
ought to earn for it the utmost protection. 
MOUNTAIN BLUEBIRD. 
( Sialia currucoides. ) 
The mountain bluebird is an abundant breeder throughout the 
higher altitudes of Utah and in spring and fall is a migrant in the 
irrigated valleys. In the spring flocks of 5 to 15 often may be seen 
in the vicinity of infested fields. In their search for food, usually 
confined to the borders of fields and along roadsides where fences and 
telephone poles afford favorite perches, the bluebirds come in contact 
with hibernating or recently emerged adult alfalfa weevils. A con- 
siderable number of bluebirds were encountered in April in the Salt 
Lake Valley, and in July they were found in post-breeding flocks in 
alfalfa fields in the Weber Valley. At the latter place the fully 
fledged young were feeding extensively on the larvae, which were then 
present in great numbers. 
Of seven birds collected in April five had fed on breeding weevils. 
In bulk the weevils composed over 4 per cent of the food and were 
taken at an average of about two and one-half per bird. Twelve 
was the highest number recorded for any individual. 
The major portion of other animal food at this time of year con- 
sisted of caterpillars (32.5 per cent) and ground beetles (31.3 per 
cent). In one stomach eight cutworms formed about four-fifths of 
the food and in another a similar number composed over 72 per cent. 
Among the ground beetles the genus Amara predominated. Crickets 
appeared prominently in two, and in one a large number of dung 
beetles (Aphodius) formed about two-thirds of the food. 
Each of the nine birds collected during July had fed on the insect, 
which amounted to 11 per cent of the food. One, a juvenile bird, 
had eaten at least 70 of the larvae, forming 40 per cent of its food ; 
another, 17 larvae and 5 adults; and a third about 12 larvae and 3 
adults. 
The remaining animal food of the bluebirds at this time was char- 
acterized by a large proportion of hemipterous remains made up 
largely of the small cicada (Platypedia putnami) , so abundant among 
the oak chaparral of the foothills. 
The mountain bluebirds, like many other spring and fall migrants, 
render their most valuable services as weevil destroyers in early 
spring. More extensive investigations of their general food habits 
