BIEDS IN RELATION TO THE ALFALFA WEEVIL. 5 
In the Salt Lake Valley the bulk of the larvae appear in May and 
June, but at higher altitudes somewhat later. The period of greatest 
abundance is at the time of the first alfalfa harvest. The insects 
usually make heavy inroads on the first crop and after the harvest 
do serious harm by retarding the growth of the second crop. All 
new shoots are devoured as soon as they appear, and a field frequently 
remains barren for three to five weeks after the first cutting. 
When full-grown the larvae cease feeding, drop to the ground, and 
spin rather loosely woven cocoons, which are often attached to dry 
vegetation at the base of the plant. The insect now passes through 
the pupal stage and in from one to two weeks emerges as the adult. 
In this stage it is covered with many fine scales or hairs which give it 
a light brown color. The adults begin to appear in large numbers 
about the first of July and may often be found clustering by hun- 
dreds upon vegetation about the borders of recently cut fields or 
near the bases of newly constructed haystacks. Frequently they feed 
upon the foliage and scar the stems of plants other than the Le- 
guminosse; the writer has seen healthy amaranth plants laid pros- 
trate in a comparatively few hours. 
After a short period of flight, when again some may fall prey to 
birds that feed on the wing, the insects seek hidden places for the 
winter's hibernation. Beginning soon after early August the weevils 
appear less in evidence. 
DISTRIBUTION OF WEEVIL-EATING BIRDS IN THE TERRITORY 
COVERED BY FIELD WORK. 
The following somewhat general synopsis of the distribution and 
relative abundance in Utah of native birds will give a fair idea of 
the species most available as aids in the fight against the alfalfa 
weevil. This, combined with details regarding each species, as later 
presented, will show which birds are doing the most good in any 
locality. 
One of the regions most severely infested by the weevil was that 
immediately south and southwest of Salt Lake City, extending east 
and west to the edge of the irrigated land. This has an average 
width of 4 miles and through it flows the Jordan River. In 
this area the English sparrow is the most abundant bird. Next 
comes Brewer's blackbird and in smaller numbers are the red- 
winged blackbirds, which confine the bulk of their feeding to the 
vicinity of marshes along the river or places where lack of drainage 
has produced ponds. Following these are Brewer's, vesper, and lark 
sparrows, and meadowlarks. Robins, though very numerous in 
migration, are not so frequently met at a later date. The remaining 
common birds, named approximately in the order of their abundance, 
