gyi 2s ROBIN ROOSTS., 
erally too many for me. The difficulties of 
the work, it should be explained, are greatly 
enhanced by the fact that at the very corner 
where the influx is largest none of the low- 
flying birds can be seen except for a second 
or two, as they dart across a bit of sky be- 
tween the roost and an outlying wood. To 
secure anything like a complete census, this 
point must be watched continuously; and 
meantime birds are streaming in at the 
other corner and shooting over the distracted 
enumerator’s head, and perhaps dropping 
out of the sky. I conclude, therefore, not 
that the roost had increased in population, 
but that my last year’s reckoning was even 
more inadequate than I then supposed. 
Even with two pairs of eyes, it is inevitable 
that multitudes of birds should’ pass in un- 
noticed, especially during the latter half of 
the flight. I have never had an assistant or 
a looker-on to whom this was not perfectly 
apparent. 
As I stood night after night watching the 
robins stream into this little wood,— no bet- 
ter, surely, than many they had passed on 
their way, — I asked myself again and again 
what could be the motive that drew them to- 
