Cambridge, Mass.
1903.
July 22
(No 2)
watched them go last summer a very large number of
birds (certainly more than 100) departed all together
with a prodigious whirring of wings like that of a
big bevy of quail. Nothing of the kind happened this
morning, at least while I had the roost under
observation. On the contrary, the birds left it, as they
came to it at evening, a few at a time, the number
on wings at any one time seldom exceeding a dozen
and ordinarily amounting to not more than one half
of that while frequently they went out singly or in twos
and threes. Nearly all of them started well upwards
(at an angle, usually, of at least 45 degrees) making a loud
whining sound with their wings. This is seldom heard
at evening for then they usually approach the roost
on a level or descending plane and quite silently as
far as their wings are concerned. Somewhat to my
surprise I found that they snapped their bills
almost as frequently and quite as loudly this
morning as they ordinarily do when taking their
perches at wing, producing the same
nearly incessant sound which so strongly resembles the
pattering of hail or heavy rain drops striking the
leaves. I have hitherto supposed that they snapped their
bills to intimidate other Robins who were crowding
in on the perches that they had chosen but it now
seems doubtful if this explanation will hold good
although it may be that they move about among the
bushes sufficiently before taking flight to irritate
one another. Certainly the foliage was at times
a good deal agitated by their movements although
less so than is often the case at evening.