(es) 
GATES—SuUMMER Birp Lire In ILLINots. 
Some GENERAL FACTORS. 
Most important for maintaining an avian population is the 
food problem. This region is especially prolific in food sup- 
ply for insectivorous birds. Insects are present in vast num- 
bers, especially in the various bayous and lakes, which are part 
of the river system. Among the most plentiful insects were 
dragonflies, mayflies, beetles, flies, caddis flies, and chirono- 
mids. 
An idea of the abundance of insects, especially of the may- 
flies, may be gathered from the fact that during their period of 
emergence, the adult mayflies (or as they are called in this re- 
gion, “willow flies”) collect so thickly around the lights of 
Havana during the night that the following morning these 
insects must be swept up and carted away to avoid the stench 
from their decaying bodies. On the morning of July 7, 1910, 
the second day of the emergence of Hexagema bilineata* 
three piles of insects 3.5 feet in diameter and 1.5 feet high 
were seen on Main street in Havana. Around the lights 
at the foot of the bluff the street and part of the shore was 
carpeted with these insects to a depth of four to eleven inches. 
Herbivorous birds do not fare so well in the region during 
summer. In but very little of the area can ruderal plants 
grow and form weed patches. Most of the plants whose seeds 
are eaten by birds matur their seeds during late summer and 
autumn and in consequence are of little attraction to summer 
birds. The town, itself, is surprisingly free from weed patches 
of more than a very limited extent. For this reason, perhaps, 
the English sparrows which are naturally attracted to the 
nois River and its basin. Bulletin Illinois State 
Laboratory of Natural History, 6:98-251. 
Hart, C. A, and Gleason, H. A. On the Biology of the 'Sand Areas 
1907 in Illinois. Bulletin, Illinois State Laboratory of 
Natural History, 7 :139-148. 
Gleason, H. A. The Vegetation of the Inland 'Sand Deposits of Illi- 
1910. nois. Bulletin, Ilinois State Laboratory of Natural 
History, 9 :23-174. 
+ Determination furnisht thru the kindness of Mr. Chas, A. Hart 
of the summer session staff. 
