Date: 1/29/19 7:43 pm From: Arthur Shippee via CTBirds <ctbirds...> Subject: Re: [CT Birds] Portland Great Black Hawk
From Avian Haven, ME: Great Black Hawk – update 1/29
We are extremely sad to report that the hawk’s feet have deteriorated markedly in the last 24 hours. It now appears that at least two toes on each foot will most likely be lost, and we are concerned that the overall viability of both feet has been compromised. We will be doing further diagnostics tomorrow.
Some of you have asked why this individual was susceptible to frostbite, when our northern hawks seem to do fine in cold weather. This essay http://askanaturalist.com/why-don%E2%80%99t-ducks%E2%80%99-feet-freeze/ describes the “rete mirabile” or “retia” (basically, a net-like heat exchange mechanism between the arteries and veins) in birds’ legs. Perhaps the key sentence is “birds that live in cold weather habitats tend to have more elaborate retia.” It seems logical that a species native to a warm climate would not have the kind of mechanism needed for legs and feet protection from extreme cold. Also, the very long legs of this hawk might have made it difficult to tuck a leg completely under the body plumage to protect it from the cold.
With regard to suggestions of prosthetics: At least in theory, one prosthetic foot could serve as a sort of crutch for a remaining natural foot that was fully functional but in this case, both feet are affected.
Thank you all so much for your prayers, good wishes, love and support for this beautiful bird.