Also, because bird feet are not vulnerable to frostbite (except, in the case of feeder birds, for doves and pigeons, which pig out, filling up their crops and then spending the next several hours roosting, hunkered down with their bellies against their feet), they have virtually no nerve endings to register pain, so they don't feel hardly any warmth or cold via their feet.
Best, Laura Erickson Duluth, MN On Fri, Feb 5, 2021 at 10:59 AM Michael Koutnik <m.a.kout...@gmail.com> wrote: > How timely. Thanks for sharing! > > On Fri, Feb 5, 2021 at 10:48 AM Jeff Ranta <rant...@gmail.com> wrote: > > > I remember a student asking the same question in a High School Gen Bio > > class I taught for years at Stillwater Area High School. I dug out one > of > > my old ornithology text from college and found a fascinating answer. > > > > I found a similar answer on The Cornell Lab All About Birds website > > copied below: > > > > Birds such as gulls and ducks endure long periods of standing on ice via > > regional heterothermy, or maintaining a core body temperature while > > allowing the temperature of extremities to deviate from the core > > temperature. > > > > Keeping an entire foot warm requires a tremendous energy cost. Instead, > > these birds allow the foot to approach freezing temperatures. Blood is > > still supplied to the foot, however, so the birds use a countercurrent > heat > > exchange system—cool blood coming back from the foot travels through > veins > > grouped around arteries that are sending warm blood from the body to the > > foot. Heat is transferred from the warm arteries to the cool veins. > > > > This countercurrent heat exchange system is very efficient at maintaining > > heat in the core. Periodic increases in blood flow allow a little heat to > > reach the foot and prevent it from freezing. > > > > Bird feet can also withstand low temperatures without damage because > there > > are mostly tendons and bones with little muscle or nerve tissue. Since > this > > is not the case for human feet, our own countercurrent exchange systems > do > > not prevent frostbite. > > > > Great topic! > > > > Jeff Ranta > > Stillwater, MN > > > > > > > On Feb 5, 2021, at 10:21 AM, Judith Clayton <judit...@theriver.com> > > wrote: > > > > > > I have a heated birdbath that is about 25 degrees off level. > > Frequently, part of the heated pan is without water. I have found it > > curious that with a warm dry surface, birds are not heating their cold > feet > > there. And so, how do birds care for this necessary part of their > anatomy? > > > Thanks! > > > Judy Alexandria (Douglas County), Mn > > > > > > It is in the shelter of each other that people live. > > > > > > Irish Proverb > > > > > > ---- > > > Join or Leave mou-net: http://lists.umn.edu/cgi-bin/wa?SUBED1=mou-net > > > Archives: http://lists.umn.edu/archives/mou-net.html > > > > > > During the pandemic, the MOU encourages you to stay safe, practice > > social distancing, and continue to bird responsibly. > > > > > > ---- > > Join or Leave mou-net: http://lists.umn.edu/cgi-bin/wa?SUBED1=mou-net > > Archives: http://lists.umn.edu/archives/mou-net.html > > > > During the pandemic, the MOU encourages you to stay safe, practice social > > distancing, and continue to bird responsibly. > > > > > -- > Mike Koutnik > Mobile: 612-963-5551 > makout...@gmail.com > LinkedIn: mkoutnik > > ---- > Join or Leave mou-net: http://lists.umn.edu/cgi-bin/wa?SUBED1=mou-net > Archives: http://lists.umn.edu/archives/mou-net.html > > During the pandemic, the MOU encourages you to stay safe, practice social > distancing, and continue to bird responsibly. > -- Laura Erickson Duluth, MN she/her/hers For the love, understanding, and protection of birds www.lauraerickson.com www.patreon.com/lauraerickson You were made and set here to give voice to this, your own astonishment. —Annie Dillard Please consider the environment before printing this e-mail. ---- Join or Leave mou-net: http://lists.umn.edu/cgi-bin/wa?SUBED1=mou-net Archives: http://lists.umn.edu/archives/mou-net.html During the pandemic, the MOU encourages you to stay safe, practice social distancing, and continue to bird responsibly.
