10 THe Witson Butretin, No. 74. 
limits of the breeding ranges of most of our aquatic birds and 
this explains the absence of many water birds which one 
might well expect to find in such country as this. 
Speaking in the strict sense of the term, the summer’s 
work revealed but two members of the group of aquatic birds 
which spend most of their time in the air over the water, 
namely, the black and the common terns, of which the former 
was by far the more abundant. Apparently they spent most 
of their time in the northern part of Thompson’s Lake, but 
two or three birds were liable to be seen almost any time in 
the vicinity of the Biological Station, over Flag Lake or the 
Illinois River and following every brisk northerly wind flocks 
of 25-40 birds would come down the Illinois River to Havana 
Lake. : 
Aside from the strictly aquatic birds which hay been treat- 
ed of above, there are several other birds whose association 
with water is determined by the location of their food. But 
one of these birds, the kingfisher, obtains food in the water. 
The others, all of which are insectivorous birds, obtain their 
food by flying back and forth over the water. In respect to 
their other activities these birds are, however, land birds. 
The swallows are the most conspicuous members of this 
group. Little need be said of these birds as they are insec- 
tivorous and must obtain their food from the haunts of the 
insects. The presence of grackles and red-headed woodpeck- 
ers in the group seems somewhat peculiar to one used to them 
in other portions of central Illinois. The red-headed wood- 
pecker belongs rather to the bottomland forests, but these 
birds were quite often seen flying back and forth over the 
water and were observd catching insects with an agility that 
would do credit to one of the flycatchers. The grackles were 
quite fond of flying back and forth across the river, especially 
in the early dawn and in the twilight. They did not display 
markt flycatching ability, but they took what insect food they 
could obtain in flying in a course which was not character- 
ized by flycatcher-like antics. 
