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.
