Turkey Vultures are well-known for spread-wing posturing. But why do they do it?
1/1250, f/7.1, ISO 400, Canon 7D Mark II, Canon EF 500mm f/4L IS II USM + 1.4 tc, not baited, set up or called in
I photographed this vulture two days ago in Box Elder County, Utah. This pose is usually assumed in full sunlight on morning perches with the dorsal side of the bird facing the sun and they may hold the posture for up to 15 minutes. The behavior likely has several functions in different situations – allowing for heat loss when the bird is too warm, heat gain on cool early mornings and wing drying when the feathers are wet. I’ve also heard it suggested that they may sometimes be using ultraviolet light from the sun to kill bacteria on their plumage from their last decaying meal.
1/2000, f/6.3, ISO 400, Canon 7D Mark II, Canon EF 500mm f/4L IS II USM + 1.4 tc, not baited, set up or called in
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I’m including this image just because it amuses me – the vulture is eyeball to eyeball with a flying insect. If you compare the first two images you can see that the bird has turned its head slightly to look directly at the “bug”.
1/3200, f/7.1, ISO 400, Canon 7D Mark II, Canon EF 500mm f/4L IS II USM + 1.4 tc, not baited, set up or called in
Here we see the behavior from a different angle.
Turkey Vultures maintain a lower body temperature at night than in daytime and they likely also use spread-wing posturing in the morning to raise their core body temperature to the daytime level. These images were taken early on a cool morning so I suspect that’s exactly what this bird was doing.
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1/2500, f/7.1, ISO 400, Canon 7D Mark II, Canon EF 500mm f/4L IS II USM + 1.4 tc, not baited, set up or called in
Here’s a closer look at the bird as I passed it near the road. There were many road-killed rabbits and several dead sheep in the area so I suspect that this bird and its companion (out of frame to the right) won’t go hungry for some time to come.
And they’ll provide us a cleanup service as a bonus.
Ron
Source: https://t-tees.com
Category: WHY
