Cambridge, Mass.
1906.
Feb. 26
(No 2)
  As I was watching a Flicker this morning, in one of
the big elms on (?) Street, opposite the Botanic Garden,
a Sparrow Hawk stooped at it, evidently in play,
passing within a foot of it. The Flicker gave a
perceptible start but did not leave its perch. The
Sparrow Hawk then alighted on a dead branch near
the top of the tree and within ten feet of the
Flicker. Here it remained several minutes, preening
its feathers. A funeral procession passed through the
street directly beneath it without alarming it and
the bird did not seem to notice me as I stood
on the sidewalk looking up at it. The tree it was
in is full of holes in one of which Screech Owls have
nested for many years. I wonder if the Sparrow Hawks
are thinking of nesting there this season!
  Four or five Chickadees, collected in the cluster of lilacs
at the rear of our house, were indulging, early yesterday 
morning, in a performance which I have often witnessed
in early spring. They were continually flying back and forth,
or in irregular circles, over and through the lilacs, making
frequent sharp, angular turns and sometimes doubling back.
They moved in short, jerky, undulating flights quite different
from those which they make on ordinary occasions.
Sometimes three or four birds would be on wing at once,
sometimes but one or two. Often one would follow in
the track of another, several yards in the rear, and
evidently, as it seemed to me, in playful but rather
listless pursuit of the leading bird. It seemed to be a kind
of aerial dance of Chickadee minuet, as nearly as I
could understand it. The birds chirped a good deal but did
not once utter the phoebee call.