I recall a conversation once with someone who had trapped, tagged, and released vultures in an area with both species that Black Vultures are far, far more aggressive than Turkey Vultures towards creatures of all sizes.

Here is an article about the two different species that had the following to say about Black Vulture behavior: They routinely eat nestling birds, from seabirds to herons, and they congregate in large numbers on tropical beaches to harvest hatchling sea turtles. Eggs are eaten as well, from bird to reptile. Newborn mammals such as pigs and calves may be killed, or the afterbirth may be consumed. There are reports of black vultures snipping the tails off small mammals, and having handled this species and seen how it pulls on anything stringlike I can well believe it.

 Since the heart of the Fish Crow's range is well within the heart of the Black Vulture's range, I would imagine there has been a strong past genetic selection for knowing the difference between Black Vultures and other vultures or raptors, even if a Missouri Fish Crow is not likely to encounter a Black Vulture.

Phil Wire
Troy, MO
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On Mon, May 16, 2016 at 6:06 PM, bryan prather <[log in to unmask]> wrote:
Warson Woods, Mo 63122

Saturday, 5/14, I observed 2 Am. Crows trying to gain altitude to ward off a potential threat.  Lots of hollering by them was also a part of this action.  I believe they have a nest nearby, although I haven't confirmed it.

Initially, I looked up and  I indeed saw a soaring bird that was circling slow as if to gain altitude via a thermal.  That was the Crow's target.  Vulture was my initial thought, but I thought why would Crows care about that.  Maybe it was an im. Bald Eagle soaring past instead.  I grabbed my binoculars and saw that the perceived intruder was a Black Vulture.  First for me at this locale,
my work, but great!

My question is why did this Black Vulture turn on a mobbing mentality.  They leave the Miss. Kites alone and I haven't seen them do this with TVs, although I haven't seen a lot of Turkey Vultures float over this location.

There are 6-8 Crows that hang here all year.  They battle w/the Cooper's hawks that visit on occasion but they don't participate in the fall/winter roost that I see flying over the store then.  Numbers at that time approach 500, from what I've seen flyover.

Just curious,

Bryan Prather
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St. Louis Co., Mo

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