Concord Mass.
Ball's Hill.
1900
May 29
(No 2)
yards. He spent most of his time on the ground picking
over the soggy dead leaves near the edge of the river but
once he mounted into some alders and flitted from
twig to twig jumping up after insects which were clinging
to the under sides of the leaves above him.
  As I have already said I saw during the day at
least 50 Canadian Warblers a number wholly unprecedented
in my previous experience. They were simply everywhere
in the greatest abundance of course in the swamps
and dense thickets near the river but by no means
uncommon on the sides & even tops of the hills where
I noticed several feeding high up in the oaks & pines in
company with equally numerous Black-polls. It
is easy to recognise the Canadian Warbler at a distance
or in poor light by his abrupt, jerky movements &
especially by the frequent, nervous, upward twitches of his
long tail.
Canadian
Warblers
in
unprecedented
numbers
  The Water Thrushes were also scattered about everywhere
on the sides & tops of the hills in the driest possible
situations. That this was due not to individual choice
but to the overcrowding of the swampy thickets was
evident for I repeatedly saw birds fly from the
side of Ball's Hill into the thickets along the river & the
next instant return hotly pursued by another Water Thrush
whose haunts they had invaded. In other words each
bird in the river thickets evidently monopolised &
stoutly defended a certain portion of those especially
choice feeding grounds. One or two Water Thrushes
were singing near the cabin in the early morning
but they have been more silent this spring than
is usually the case.
Water Thrushes
in dry
woods on
tops & sides
of hills.
107