epressed the next year, perhaps reflecting the reduced 
90d supply following the insecticide application. 
pecimen Data 
In our series of 58 catbird specimens (Table 7) 
wed from television tower kills in central Illinois jn 
eptember and October during the past 4 years, there are 
vo distinct color types showing little or no gradation. 
oth types are represented in all age and sex classes. 
me type, presumably representing the nominate race, 1s 
arker with very dark bay crissum. The other form js 
»cidedly pale, especially on the belly and crissum, the 
‘issum being rufous brown. 
In all respects the paler birds show the characters of 
e western race, ruficrissa (Aldrich 1946, Phillips, et al. 
164), and we are tentatively considering them as that 
rm. There are several reasons for caution in accepting 
e identification. The greatest drawback is the paucity 
of recent comparative material in fresh fall plumage. 
Except for our own series, most of the catbird specimens 
we have seen are so old as to be almost worthless for color 
comparisons. We are also concerned by the high propor- 
tion (nearly 50 percent) of ruficrissa in our collection. 
Is there, in fact, such a notable migration of western 
birds through east-central Illinois? On the other hand 
Aldrich (1946) included the West Indies in the winter 
range of ruficrissa, in which case Illinois can very well be 
on the migration route. Also, Phillips, et al. (1964) noted 
that the ruficrissa population migrates eastward, and we 
now believe that many western catbirds do migrate 
through Illinois. 
Students in other parts of the state can also shed more 
light on the problem by preserving large series of speci- 
mens from local tower kills. Comparative series from 
southern and northern Illinois should prove particularly 
interesting. 
Taste 7.— Weights and measurements of fall (September-October) catbird specimens killed in east-central Illinois. 
e and Sex Number of Gross Weight (grams) Wing Length (mm) Tail Length (mm) — Culmen from Nares (mm) 
Specimens Range Mean Range Mean Range Mean Range Mean 
ult male 11 Jo.4-4275 39.0 87 8-94 .5 Sil 7 89 .6—98 .0 J3R9 122-1307 IBC 
mature male 21 S454 4912 “40.1 840-9203 88.3 83 4-94 9 SO). 7 OS sm 12.0 
ult female ) ie tO 37 oF OS). 5=Oil 88.5 S70=9576 Sil 2 WINGS 12.8 
mature female 17 3326-44515 938-6 83 .8-88 .3 86.0 83,090). i S7 il Al 2D (3) 1220 
23 
