Tuesday, February 05, 2008

Some notes on courtship...

So, what exactly prompts birds to sing and know when to nest? For the most part it is photoperiod--or the amount of daylight--that causes hormones to flow that ignite the instinct to reproduce. Here in Central Ohio, Carolina chickadees, tufted titmice and house finches have begun singing as a result of longer days, even though actual nesting won't take place for some time.

The same is true of our peregrine falcons. Even though we shouldn't expect eggs until March, the amount of daylight will trigger courtship behaviors to start. We are especially excited this year to have the live, streaming video with audio to assist us with witnessing early nesting behavior in addition to the egg laying, incubation, etc.

Here are some displays to watch for at the nest ledge:
"Head-Low" - done by the male or female in which the bird lowers its head in relation to the rest of its body.
"Bowing" - also done by both sexes; head and upper body move repeatedly up and down
The call that may accompany either or both of these displays is:
"Creaking-Call" - a 2-syllable call with the emphasis on the first syllable. Often described as sounding like a squeaky hinge.

These behaviors can be seen all seasons of the year but especially during courtship as the mated pair approach and greet each other after being apart.
Mate-feeding is also important during courtship. More on that to come-stay tuned!