HAWKS AND OWLS: 
Population Trends From Illinois Christmas Counts 
RICHARD R. GRABER AND JACK S. GOLDEN 
In 1900 the Audubon Societies, parent organizations 
of the National Audubon Society, inaugurated the Christ- 
mas bird census. This census was introduced and briefly 
outlined in the societies’ official organ, Bird-Lore mag- 
azine (Chapman 1900:192), and two or possibly three 
aims were suggested. The first stated purpose was that 
the Christmas census would serve as a harmless “‘hunt’”’ 
or entertainment for the participants. The second, in 
the words of the article, was that it would ‘‘also con- 
stitute, in a measure, a census of Christmas bird-life.”’ 
A third purpose was implied, that is, conservation of 
wildlife. 
The Christmas census or count that has been repeat- 
ed annually for more than half a century has constituted 
a numerical record of winter bird life, but opinions of 
its value as a census vary greatly. Stewart (1954) re- 
viewed some of these opinions and suggested methods 
for eliminating several major variables in the Christmas 
census. Hickey (1955) urged that the Christmas census 
be considered a sport and implied that it should be 
largely disregarded as a scientific tool. 
Though major faunal changes are a part of our writ- 
ten history, there is no record of winter bird life in the 
United States comparable to that provided by the Christ- 
mas census. Filled with variables as these censuses 
are and have been, few persons would deny that they 
are better than a complete void, and ornithologists will 
go on making attempts to analyze the census data. The 
present study is such an attempt, and its purpose is 
twofold: (1) to summarize the hawk and ow! data con- 
tained in the published counts from 1903 to 1955 for 
Illinois, and (2) to uncover any general trends in winter 
hawk and owl populations in Illinois. 
Richard R. Graber is an Associate Wildlife Specialist with 
the Illinois Natural History Survey. 
At the time of this study, Jack S. Golden was a Technical 
Assistant with the Illinois Natural History Survey. 
The manuscript was edited and the booklet designed by 
Diana R. Braverman of the [Illinois Natural History Survey 
editorial staff. 
The cover photograph of a red-tailed hawk and all other 
photographs were taken by William E. Clark, Illinois Natural 
History Survey photographer. Only the saw-whet owl was 
photographed in the wild. 
METHODS USED IN INTERPRETING CENSUS DATA 
Data for each species of hawk and owl and each 
locality in Illinois were tabulated from Bird-Lore (1903- 
1940), Audubon Magazine (1941-1946), Audubon Field 
Notes (1947-1956), and The Audubon Bulletin, the last 
the quarterly publication of the Illinois Audubon So- 
ciety (1933-1956). The earliest censuses (1900-1902) 
were so short and sketchy that they were not used in 
this study. 
To eliminate bias introduced by censuses that were 
made at feeding stations or in urban situations where 
raptors were not likely to be seen, only the 527 counts 
recording at least one bird of prey were included. (As 
used here, ‘‘count”’ refers to the record for one locality 
in one Christmas census.) The figures for frequency of 
occurrence given in text and histograms were derived 
from these counts. 
In attempting to determine trends of raptor popula- 
tions in the 1903-1955 census period, we used only 
part of the 527 counts. For determination of long-term 
trends in density, it was necessary to have as nearly 
complete a record as possible and still to eliminate, 
without bias, the largest variables, such as the total 
number of observers participating at each census locality 
and the number of observers in each individual census 
party. Thus, the graphs showing annual fluctuations of 
raptor populations during the period 1903-1955 are based 
on the 277 counts in each of which no more than 10 per- 
sons took part and no individual census party consisted 
of more than four persons. 
Data from counts in northern, central, and southern 
zones of Illinois were treated separately. These divi- 
sions of the state, figs. 3 and 4, are the same as those 
used by Smith & Parmalee (1955:2). Each census local- 
ity is preceded by the name of its county; counties in 
each zone are listed in alphabetical order. 
Census localities in northern Illinois were: Bureau 
(Ohio, Princeton); Cook (Arlington Heights, Blue Island, 
Chicago, Des Plaines, Elk Grove Forest Preserve, 
Evanston, La Grange, Orland Park, Palos Park, Park 
Ridge, River Forest, southeastern Cook County, Stick- 
