34 TEES Add Dae BIN Bab) a et eave ea 
By the method of computation for individual lists, zero was the 
best possible score (no deviation from the normal) and 1457 was the 
worst possible score (complete and total deviation from the normal). 
It is perhaps significant that the three highest scores were made by 
persons with a background of long and serious field work in the region. 
They were remarkably close together; i.e., 421, 422 and 429. The eight 
highest scores were under 500, which indicates an average agreement 
on approximately two-thirds of the list. 
The red-winged blackbird was the only bird placed at the head 
of a list by every person contributing. The other four most abundant 
birds—herring gull, spotted sandpiper, meadowlark and robin—were 
placed at the head of their lists by 85% of the contributors. Some birds 
found places on two or more lists, indicating that they were regarded 
as important elements of the avifauna of more than one habitat. They 
were: 
Song Sparrow—7th in Wood- Flicker — 8th in Woodland, 
land, 8th in Open Country, 13th in Open Country. 
aL WOE MENS Tree Sparrow—12th in Open 
Herring Gull—lst in Open Country, 16th in Woodland 
EMR MERE (Cd Starling—2nd in Woodland, 
Bonaparte’s Gull—4th in Open 9th in Open Country 
Eee tn eget Killdeer—2nd in Beach, 11th in 
Coot—3rd in Open Water, 4th Open Country 
in Marsh Crow—10th in Open Country, 
14th in Woodland 
The five habitats selected do not, of course, completely cover the 
range of habitats in the Chicago Region. Swallows, for example, 
with the exception of the purple martin, did not place on the lists. 
Tree swallows and bank swallows certainly should be considered among 
the seventy-five most abundant species in the region. Almost with- 
out exception, each species has its own ecological niche and the five 
categories used are, at best, composites of general habitat types. It 
is to be hoped that further work along different lines will help to prove 
or disprove the estimations of relative abundance that this investiga- 
tion has produced. 
Field Museum of Natural History. 
