1903.
April 5
  Cloudless with strong N.W wind. Bitterly cold, the ground
frozen hard this morning & icicles hanging from the trees & bushes
all day exposed to direct light of the sun. The ice on the
tree in front of the house was 1/4 of an inch thick. Walter 
Deane tells me that the thermometer fell to 26 degrees in Cambridge
early this morning. Only a very few plants show signs of injury.
Hyacinths in full bloom are not apparently in the least harmed.
  Spent most of the day in the woods visiting Prescott's
Pines & Birch Field in A.M; Davis's Hill & Ball's Hill in
P.M. The birds kept close hidden & silent for the most
part but Song Sparrows & Bluebirds sang a little at sunrise
and I heard three male Pine Warblers in full song in 
Lawrence's Woods in the forenoon. Saw a single Fox Sparrow
in Pine Park late yesterday afternoon and five together 
in the bush by the river near Benson's landing this afternoon.
A Fish Hawk soaring about over the river just above
Ball's Hill.
  Heard a Cooper's Hawk barking this morning in the
woods near Pulpit Rock. At evening the same bird 
flew from the elm in front of the barn, as we
stepped out of the shed, & flew off barking. I hope he is
not going to settle on the farm. His flight this
evening was remarkable. He sailed all the way from
the elm to the woods without ever flapping his wings
moving very slowly yet as buoyantly as a bit of thistledown.
His wings looked very short & broad. I mistook him
for an Owl until I heard his characteristic cry.