12 THE AU. Di BONe (Bt bE Bee 
1973 BREEDING BIRD SURVEY 
by MARYANN GOSSMANN 
Although Illinois birders participate in the U.S. Fish and Wildlife 
Service’s annual Breeding Bird Survey (BBS), 100% coverage of the 64 
routes has not vet been attained. The most recent figrues available from 
the Laurel, Maryland headquarters are for the 1973 Survey. 
The BBS only began in Illinois in 1966 and is therefore rather new. 
Prior to 1969, very few routes were surveyed each year making it im- 
possible to compare the earlier results with present findings. Each year the 
total number of survey routes completed continues to increase, reaching 
the high of 53 in 1973. Flooding and road construction prevented the com- 
pletion of other routes in 1978. 
Habitats vary greatly throughout the state and so do the numbers of 
species recorded along the various routes. The average number of species 
recorded per route in 1973 was 48; the range was from 30 to 70 species. 
As would be expected, those routes with the greatest varieties of habitat 
were responsible for the larger numbers of species while those in urban 
or intensive row-crop areas yielded the lowest numbers. A total of 134 
species and 63,221 individual birds were counted this year. 
The information gathered by compilers of the BBS routes each year 
is transferred to a central computer at Laurel for analysis. Illinois results 
are added to results from all the other states and then the total continental 
analysis will show changes in populations of each species throughout its 
entire range or throughout just portions of that range. That is why it is 
important to complete every route every year—preferably by the same 
observer each year. 
Without benefit of computer analysis, it is possible to make some 
comments and comparisons of Illinois results. There is little apparent 
change in bird populations within the five year span of 1969 through 1973. 
The average number of birds per route remained constant at 48 per route. 
The average number of individuals per route decreased slightly from 
1,286 to 1,193. The total number of species found each year has increased 
from 118 to 134 which may be due to the greater number of routes sur- 
veyed and perhaps the increased skill on the part of the observers rather 
than actual changes in birdlife. 
Blackbirds, a menace in the winter in some localities, have shown 
a slight decrease in numbers from 1969 to 1973; only the Redwinged 
Blackbird has shown an increase: from 181 to 189 birds per route. 
As might be expected, only a few species were found on all routes 
surveyed. Grackles, Redwinged Blackbirds, Eastern Meadowlarks, House 
Sparrows and Starlings would be expected; Robins, Barn Swallows and 
Mourning Doves were also found on every route. Several additional species 
were reported from all but one or two routes. 
By the time this report is printed, the 1974 Breeding Bird Surveys will 
have been completed; however, there are still several routes that need to 
be assigned to competent birders interested in gathering knowledge about 
our changing bird poulations. Anyone interested in additional information 
regarding the BBS or the availability of routes for 1975 should contact 
the author at Rt. # 1, Box 71, Plainfield, Ill. 60544. 
