Concord, Mass.
1910
May 19
[May 19, 1910]

Remarkable sexual act by pair of Phoebes

  On May 12th I visited the cellar under the little shop
on the Ritchie place finding there a Phoebe's nest with four eggs. I
examined the nest again yesterday afternoon when it held five eggs.
On both occasions the eggs were cold. On neither did I see or 
hear a bird about the place. But as I was approaching the
shed this afternoon (about 5 o'clock) a Phoebe came flying
swiftly towards me from the direction of the cellar closely
followed by another. After several sharp turns & twists the
two birds came together in the air at a height of about
15 ft. and thence descended rather slowly to the earth
clinched together and whirling around and around. At first
I thought it was a fight between rival males but when
I got within 15 or 20 feet I saw that the birds were
copulating. Never before have I seen the sexual act performed
in anything like the same manner by birds of any kind.
It lasted at least five minutes during which the contact was