172 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. 1 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- 



