Cambridge, Mass
1910
March 2 [March 2, 1910]
  Clear, calm & mild but chilly
  About 8 A.M. I was looking out of one of the north
windows of our home when a [male] Sparrow Hawk appeared
coming low over the garden towards me, flying nearly
straight and very sluggishly with long, slow, irregular wing
beats. On reaching the house he rose and apparently
passed over it although that I could not see.
Sparrow 
Hawks
  At 9.30 am, as I was waiting in the museum, I
heard his shrill screaming. Rushing out I again saw him
pass over the Garden taking nearly the same course as at
first but at a greater height so that when he came to the
house he cleared the tops of the big lindens about it
without rising perceptable [perceptibly]. Thus far he had flown nearly
straight and very swiftly, vibrating his wings incessantly;
but on reaching Hubbard Park and turning to the westward
he began soaring in circles, still screaming at intervals.
I now saw for the first time a [female] Sparrow Hawk circling
in silence about 100 yards from the [male]. Keeping about
this distance from one another the two birds drifted off
towards the south-west & were soon lost to my sight.
  About 10 A.M. the [male] again appeared circling about
our lindens with loud cries (kleur-kleur-kleur), swooping
downward nearly to the earth from an elevation of 80 ft
or more and then rebounding as it were to this height
to immediately descend and rise again. These evolutions
may be represented by a series of deep loops [diagram]. They
were not unlike those which I have repeatedly seen the
Marsh Hawk & the Cooper's Hawk perform in early
spring but even more spirited & graceful. Without
doubt they were love flights. I saw no female this time, however.