Friday, 26 December 2014

Black Vultures

Aegypius monachus is a species that we see fairly often in Portugal, most frequently in the Baixo Alentejo but also, from time to time, in the Algarve.  We usually refer to it as Black Vulture or sometimes Eurasian Black Vulture, which are the names used in the Collins Bird Guide and which have been in use as far back as one cares to look.

Eurasian Black Vulture
 American Black Vulture

However, just a few years ago came the IOC World Bird List, the list of recommended English names for all the world’s birds.  Now we were urged to refer to Aegypius monachus as Cinereous Vulture.  This change was proposed with the intention of avoiding confusion with Coragyps atratus, the Black Vulture of the Americas.  Just who proposed the name Cinereous, meaning ‘ashy-grey’ isn’t clear.  Presumably it was someone who had never been fortunate enough to see one of these huge birds, which may not be black but which are certainly not ashy-grey.

American Black Vulture

At about the same time, the British Ornithologists’ Union somewhat bizarrely, proposed a change of name, not to Cinereous Vulture, but to Monk Vulture.  Not surprisingly, this didn’t gain widespread acceptance but did add to the confusion for a while.  The suggestion that Coragyps atratus should be called American Black Vulture while Aegypius monachus remained Eurasian Black Vulture was rejected, possibly on the grounds that it was too simple but more likely because the Americans involved in the decision making could not come to terms with ‘their bird’ having to be anything other than simply Black Vulture.

None of this is new, of course, but the subject was recently a topic of conversation while we were in Florida where (American) Black Vulture is a very common bird that we saw every day.  This is a species that has increased in numbers quite significantly during the last 25 years but it’s an increase that has brought a variety of problems and conflicts as the birds have adapted to living in close proximity to the human population.

American Black Vulture feeding on Armadillo

For some years vultures have been reported causing damage to residential and business property. Their droppings can kill trees and are said to create unsanitary and unsafe working conditions at power plants, refineries and communication towers. They can sometimes appear aggressive towards people and they harass and sometimes kill livestock.  In flight, they can be a danger to aircraft.

And they routinely cause damage to parked motor vehicles by pecking at windscreen wipers, sunroof seals, and other rubber or vinyl parts.  Black vultures are primarily scavengers that play an important role in ecosystems, cleaning up dead and decaying animal carcasses - they are regularly seen feeding on roadkill.  Rubber and vinyl certainly isn’t a part of their natural diet and only rarely do they eat any of it. Typically, the material is simply discarded after it’s ripped from the vehicle.  However, that’s not much consolation if it’s your shiny SUV that’s just been trashed!

You have been warned!

On our tour we first became aware of the Black Vulture problem at Myakka River State Park where there were notices on the car park warning of the possibility of birds attacking vehicles.  However, it was at Royal Palm Hammock in Everglades National Park that we saw the birds in action and felt the need to take some preventative measures.  The situation there has become so serious that tarpaulins and bungee cords are provided so that visitors can cover their vehicles and that’s exactly what we did.  Others didn’t heed the warnings and paid the price!

No one seems to know what it is that has brought about this behaviour from the vultures and there is much ongoing research into the problem, which is far from being unique to Florida.   Although the Black Vulture receives legal protection in the United States under the Migratory Bird Treaty Act of 1918 inevitably when the problem can’t be dealt with in any other way, birds are killed - about 5,000 of them annually according to the U.S.  Dept. of Agriculture.  And that’s just the ones they know about that were killed legally.

Of course, the American Black Vulture and the Eurasian Black Vulture are not closely related; similarities between the two are due to convergent evolution.   For some time it was thought that the New World Vultures were more closely related to the storks than to the birds of prey but that idea seems to have fallen from favour and some would now place them in a separate Order, Cathartiformes.  Whatever they are they seem to be quite a problem and one that isn’t going to be dealt with easily.

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