UNDER THE APPLE-TREES 
so developed and fixed. Hawks are doubtless the 
main cause of it. The hawk comes suddenly and 
strikes quickly, and is doubtless as old an enemy as 
the birds have. For ages he had been wont to swoop 
down from the air or from the cover of a tree, or has 
skimmed over the hill and in a twinkling snatched 
a feeding bird. I have seen the sharp-shinned hawk 
in winter sweep over a garden fence and snatch an 
English sparrow from a flock feeding in the street. 
I have seen one of the smaller hawks pick up a 
high-hole feeding in the fields in the same way. 
Birds feeding singly are less easily alarmed than 
when feeding in flocks, just as you and I would be. 
Fear is contagious, and a bird feeding alone has no 
alarms or suspicions but its own to disturb it. 
Since these birds left Canada and northern New 
England last October they have probably traveled 
over two thousand miles, beset by their natural en- 
emies at all times and places — in fields and marshes 
and woods; in danger of hawks and shrikes and cats 
by day, and of owls and other prowlers by night; com- 
pelled to hustle for food at all times, and to expose 
themselves to a thousand dangers. Is it any wonder 
that they are nervous and watchful? 
In returning they will be exposed to the same 
dangers. Their traveling is mostly done by night 
and it is probably by easy stages. But just how long 
any single flight is we have no accurate means of 
knowing. It would be interesting to know if the song 
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