Turkey Vultures, Black Vultures, And A Crested Caracara

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Last Sunday morning I went for an extended drive in rural agricultural country.  I started my day quite early, about 5:30 in the morning.  It was still very early when I came around a bend in the road and, to my delight, encountered a fairly large number of vultures — about 12 or 15 of them —  roosting in the sunshine.  Most of the birds were Turkey Vultures, but there were also Black Vultures and one Crested Caracara in the group.

I really like to photograph vultures.  They are fascinating birds.  One doesn’t see them roosting all that often.  Typically, once the sun gets up, they take to the air where they soar effortlessly, sometimes for hours, as they scan the ground below for possible carrion.  I was lucky in that I was out very early in the morning and the birds hadn’t yet taken flight.

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Turkey and Black Vultures and their relatives, California Condors, are not closely related to Old World Vultures.  Ornithologists used to think that they were related to storks.  Modern DNA analysis has pretty much deflated that theory.  The latest thinking is that they are distantly related to falcons.

In southern Arizona, Turkey Vultures seem to show up more often than do Black Vultures.  The two species manifest a lot of different behaviors.  Turkey Vultures tend to be solo soarers, although they will aggregate in flocks if there is carrion to be eaten.  Black Vultures are more social.  Turkey Vultures have a phenomenal sense of smell.  Black Vultures lack this asset, but they have keen eyesight, and they very often show up when Turkey Vultures find something to eat.  Both species have remarkable ability to soar on warm air currents, but Black Vultures apparently can fly a bit higher than can Turkey Vultures.  Black Vultures live year-round in southeastern Arizona, although their range is confined to a few discrete locations.  Turkey Vultures are ubiquitous in the warm months but most (not all, but most) migrate to points south in the winter.

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Black Vultures have featherless black heads whereas Turkey Vultures have featherless red heads.  A bit confusing, however, is the fact that fledgling and immature Turkey Vultures also have black heads.

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I had a good opportunity to observe these birds on Sunday as they were at first somewhat reluctant to fly.  The Black Vultures were clearly dominant.  On several occasions I watched a Black Vulture chase a Turkey Vulture off a perch.  They did so for no reason, seemingly, other than to assert their dominance.  There was no real aggression between the two species, just a lot of musical perches being played.

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If you look closely at this second photograph of a Black Vulture you’ll notice a bit of dirt clinging to the bird’s head.  It suggests that the bird recently had been rooting around in fairly damp soil.  I think that there’s an explanation for that.  Although vultures are carrion eaters they will also hunt opportunistically for insects or other life that they can capture easily.  Many of the big agricultural fields in the area are irrigated, causing the soil to be intermittently moist.  I’ve observed vultures hanging out in these fields, apparently attracted by invertebrates or other small life forms forced to the surface by the flooding.  My guess is that this bird had been foraging recently in a freshly-irrigated field.

Of this group, the truly dominant bird was the Crested Caracara.  That bird — yet another cousin of falcons — took flight immediately when I showed up.  However, it loitered in the air, flying endless lazy circles above me and the vultures.

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From time to time, and seemingly just for the sheer hell of it, it would swoop down and harass one of the vultures as it took flight.  Again, nothing serious, but a definite reminder of who was boss.

Images made with a Canon 5Diii, 400DO+1.4X Telextender, aperture priority setting, ISO 1000, f6.3, shutter speeds varied.


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