Question about bird behavior.

[Marina Scarr]

I am currently going through the Florida Master Naturalist Program and the question was posed today, "Why do we see birds standing on one leg?" One of the answers I found was that birds experience REM sleep at about 2-1/2 mins at a time and that they are sleeping when they are on one leg.

Thanks for any answers or insight you may have on this issue.

[allanrube]

I have heard that is has to do with rotating its body in relation to wind direction. I could easily be wrong though.

[John Chardine]

Never heard that one Alan.

Marina- This is an age-old problem that has only been looked at scientifically a few times. Never heard the REM sleep explanation either, and it doesn't sound right to me. Where sleep has been looked at in birds (e.g., gulls) it turns out they sleep in very short stints of a few seconds and they can sleep one side of their brain and keep the other side active.

Work done on flamingoes confirm a thermoregulatory function. First, birds' feet play a crucial role in thermoregulation. They use their feet to lose heat and to conserve heat. Arterial blood entering the feet is warm because it's comes from the body core. As it returns as venous blood, the veins are close to the arteries and can pick up some arterial heat before going up to the body core. This "countercurrent" conserves heat energy and prevents relatively cold blood from being returned to the core. In warm climates, birds still may want to conserve heat, because this saves energy and thus they make more efficient use of their food. Flamingoes stand on one leg more often when standing in water. As water is denser than air it can transport heat away from the feet more efficiently that air. If the bird is trying to conserve as much energy as possible, then standing on one leg is a conservation measure. This may not answer all examples of birds standing on one leg but I think it goes some way to answering the question.

[Andre van As]

John
Thermoregulation is a very complex subject and is nicely summarized in Wikepedia http://en.wikipedia.org/wiki/Thermoregulation#Thermoregulation_in_birds_and_mam mals.
However this does not address the issue in birds who have challenges at very cold and hot extremes of climate. Do you know if birds sweat and /or pant? I have seen them rest with their beaks open put have not noted if they are panting.

Regards

Andre

[John Chardine]

Hi Andre- Birds do not have sweat glands but they do pant. A classic example is the "gular flapping" of the Pelecaniformes. Gannets and pelicans frequently "pant" and pump air over their gular pouch in order to cool themselves. The pouch is highly vascularised, thin, moist and large in area and so provides an efficient cooling surface. Penguins cool themselves through their feet but also through their wings, which have very thin feathers on the underside. On a warm day in the Antarctic, I have often observed their underwings turn a bright pink. Cold-adapted species have many adaptations to conserve heat so are very vulnerable to overheating. A colleague of mine who works on Thick-billed Murres (Brünnich's Guillemot) in the Arctic of Canada has seen birds die on the cliff due to overheating. This is happening more frequently now with climate change.

Thanks for the Wiki link.

Added- I should say that the gular flapping of the Pelecaniformes is not really panting in the sense that they are not breathing heavily to pump the air as say a god would.

[Andre van As]

Hi John
Thanks for this informative update

Andre

[Marina Scarr]

Thank you so much for the valuable information, John. It is much appreciated.