All recrudescence means is ?regrowth,? and it refers to the enlargement of testes in male birds (and perhaps males of other taxonomic groups) under these photoperiod conditions. That produces more testosterone that causes the birds to sing. But it should be called ?The Autumnal Recrudescence of the Amatory Urge,? and check out this website for a poem about it: http://sniff.numachi.com/pages/tiAUTMRECR.html. The Susan Stiles listed as the poet is now Susan M. Smith, the world?s expert on Black-capped Chickadees and former resident of Seattle.

Dennis Paulson
Seattle


On Oct 20, 2016, at 12:00 PM, tweeters-request at mailman1.u.washington.edu wrote:

> Date: Wed, 19 Oct 2016 17:41:44 -0700
> From: <mcallisters4 at comcast.net>
> Subject: RE: [Tweeters] Bird Song in the fall?
> To: "tweeters at u.washington.edu" <tweeters at u.washington.edu>
> Message-ID:
> <mailman.0.1476990021.8420.tweeters at mailman1.u.washington.edu>
> Content-Type: text/plain; charset="utf-8"
>
> Don?t forget amphibians. Northern Red-legged frogs, Oregon Spotted Frogs, probably others call in the fall as well.
>
> I?m not sure if they?ve got any recrudescence going on.
>
> Kelly McAllister
>
> Sent from Mail for Windows 10 (which I don?t care for, by the way)