Preteens eb O NY BUT Ren N 11 
IS YOUR LATEST SIGHTING ON THE ‘HYPOTHETICAL’ LIST? 
Here’s a new compilation of Illinois 
probables, possibles, and for-certains ... 
and a plea for serious collecting 
and camera-work. 
by ROBERT P. RUSSELL, JR. 
The state of Illinois has, by far, the largest “hypothetical” bird list of any 
state in the Union. 
But this record is hardly an enviable one. 
What it reflects is high interest in birding — but a distressing lack 
of serious birders who might collect or photograph rare visitors, which 
would add, of course, a more solid scientific basis to the Illinois list. 
The fact that 50 rare species would have been collected or photo- 
graphed in the state would be far more valuable a situation than the 
supposition that 50 rare species MAY occur here. 
Since publication in 1955 of “Birds of Illinois” (Harry R. Smith & Paul 
Parmalee), considerable information has turned up concerning newly-re- 
corded species and additional sightings of previously-recorded species. All 
in all, then, the list of birds which follows is my own attempt to round 
up the Illinois species which ought to be marked “hypothetical” — a list 
which is not expected to be complete, incidentally, but hopefully which 
may inspire others to set forth knowledge of these particular species, or 
perhaps produce specimens or photographs hidden away in the attic. 
Included in the list are birds previously considered hypothetical but 
for which specimens or pictures since have been obtained. In addition, 
species which may be “escapees” or “releases” are included along with 
those reported only once by observers of unknown qualifications. (1 hope 
that serious collecting or photographing of rare species can begin in Illinois: 
Few of the booming colleges and universities in the state have adequate 
specimen collections, and perhaps they can take the initiative.) 
A hypothetical species, by the way, simply is one for which no specimen 
or foolproof picture exists in the particular state. In some circumstances, 
banding a new species provides an acceptable record. But sometimes even 
a photo cannot be acceptable. A photograph of a Roseate Tern or White- 
winged Junco is not acceptable because mutants of related species may 
closely resemble the rarer bird in the photograph. In such cases, only 
close examination of a skin will establish identity. Regardless of the ex- 
perience of the birder, there is always the chance that this was a mistake. 
(Human nature must be reckoned with.) 
Each particular case must be taken separately. Before including the 
species in the hypothetical list, let’s consider several factors: ease of identi- 
