Sunday, August 07, 2005

Rats - less nocturnal in NYC?

John Blakeman has expressed surprise that our Redtails catch so many rats. Redtails, as everybody knows, are diurnal raptors, while rats are generally considered to be nocturnal mammals.

While most of us assumed that NYC rats are just "different" the following correspondent proposes a different answer:

Dear Marie:
I have been following the discussion about red tail hunting behaviors in CP and had noticed that many of the recent reports talk of Junior bringing prey to the chicks later in the evening, 8:00 or later. Isn't it getting dusky by then, at least in the shadows of the park and buildings? John had asked if the rats are more diurnal in NYC, but I am wondering if it is the way light fades in the city that they come out a bit earlier than sunset as long shadows form with the sun prematurely "setting" behind the buildings. I don't live in NYC so I do not know the sunset and dusk-dawn times, but this is my thought.
<>Sally Seyal

PS from Marie: Good try, Sally. But it wouldn't really explain the frequent rat kills we have observed during the last decade that occurred in mid-morning, or at other times long before sunset, . I think all the recent reports of 8 pm feedings mainly reflect the fact that there are few observers around in the south part of the park in the mornings. Most of the "core hawkwatchers" seem to arrive in late afternoon or early evening, after work, perhaps.