I just located this 2012 review paper on the topic: Photoperiodic Control of Seasonality in Birds <http://jbr.sagepub.com/content/16/4/365.abstract>. In case you can't see that link from where you are, here's a brief excerpt from the abstract.
This review examines how birds use the annual cycle in photoperiod to > ensure that seasonal events--breeding, molt, and song production--happen at > the appropriate time of year ... In predictable breeders (most nontropical > species), photoperiod is the predominant proximate factor. Increasing > photoperiods of spring stimulate secretion of gonadotropin-releasing > hormone (GnRH) and consequent gonadal maturation. > -Mike On Wed, Mar 5, 2014 at 10:25 AM, Linda Post Van Buskirk <l...@cornell.edu>wrote: > I assume it's hours of daylight rather than temperature that triggers > behaviors. > > > > *From:* bounce-112921516-3493...@list.cornell.edu [mailto: > bounce-112921516-3493...@list.cornell.edu] *On Behalf Of *Robin Cisne > *Sent:* Wednesday, March 05, 2014 9:33 AM > *To:* Marie P. Read > *Cc:* CAYUGABIRDS-L > *Subject:* Re: [cayugabirds-l] A hint of things to come... > > > > Yet another reason to love birds: after a certain point in late winter, > they say, "To hell with the temperature, I'm getting on with it!" > > > > On Wed, Mar 5, 2014 at 9:01 AM, Marie P. Read <m...@cornell.edu> wrote: > > Things are looking up. Mr. Cardinal just fed Mrs. Cardinal in a tree near > my feeders. > > Think Spring! > > Marie > > > Marie Read Wildlife Photography > 452 Ringwood Road > Freeville NY 13068 USA > > Phone 607-539-6608 > e-mail m...@cornell.edu > > http://www.marieread.com > > ***NEW*** Music of the Birds Vol 1 ebook for Apple iPad now available > from iTunes > > http://itunes.apple.com/us/book/music-of-the-birds-v1/id529347014?mt=11 > -- > > Cayugabirds-L List Info: > http://www.NortheastBirding.com/CayugabirdsWELCOME > http://www.NortheastBirding.com/CayugabirdsRULES > http://www.NortheastBirding.com/CayugabirdsSubscribeConfigurationLeave.htm > > ARCHIVES: > 1) http://www.mail-archive.com/cayugabirds-l@cornell.edu/maillist.html > 2) http://www.surfbirds.com/birdingmail/Group/Cayugabirds > 3) http://birdingonthe.net/mailinglists/CAYU.html > > Please submit your observations to eBird: > http://ebird.org/content/ebird/ > > -- > > > > > -- > > ""You can observe a lot just by watching." -- Yogi Berra > > -- > > *Cayugabirds-L List Info:* > > Welcome and Basics <http://www.northeastbirding.com/CayugabirdsWELCOME> > > Rules and Information <http://www.northeastbirding.com/CayugabirdsRULES> > > Subscribe, Configuration and > Leave<http://www.northeastbirding.com/CayugabirdsSubscribeConfigurationLeave.htm> > > *Archives:* > > The Mail > Archive<http://www.mail-archive.com/cayugabirds-l@cornell.edu/maillist.html> > > Surfbirds <http://www.surfbirds.com/birdingmail/Group/Cayugabirds> > > BirdingOnThe.Net <http://birdingonthe.net/mailinglists/CAYU.html> > > *Please submit your observations to eBird > <http://ebird.org/content/ebird/>!* > > -- > -- > *Cayugabirds-L List Info:* > Welcome and Basics <http://www.northeastbirding.com/CayugabirdsWELCOME> > Rules and Information <http://www.northeastbirding.com/CayugabirdsRULES> > Subscribe, Configuration and > Leave<http://www.northeastbirding.com/CayugabirdsSubscribeConfigurationLeave.htm> > *Archives:* > The Mail > Archive<http://www.mail-archive.com/cayugabirds-l@cornell.edu/maillist.html> > Surfbirds <http://www.surfbirds.com/birdingmail/Group/Cayugabirds> > BirdingOnThe.Net <http://birdingonthe.net/mailinglists/CAYU.html> > *Please submit your observations to eBird > <http://ebird.org/content/ebird/>!* > -- > -- -- Cayugabirds-L List Info: http://www.NortheastBirding.com/CayugabirdsWELCOME http://www.NortheastBirding.com/CayugabirdsRULES http://www.NortheastBirding.com/CayugabirdsSubscribeConfigurationLeave.htm ARCHIVES: 1) http://www.mail-archive.com/cayugabirds-l@cornell.edu/maillist.html 2) http://www.surfbirds.com/birdingmail/Group/Cayugabirds 3) http://birdingonthe.net/mailinglists/CAYU.html Please submit your observations to eBird: http://ebird.org/content/ebird/ --
