‘CARRION SCAVENGING’ (2): TURKEY VULTURES ON ABACO


Turkey Vulture, Abaco Bahamas (Nina Henry)

‘CARRION SCAVENGING’: TURKEY VULTURES ON ABACO

Turkey Vultures (Cathartes aura) are causing some comment on FB at the moment, in particular about why they like to stand on utility posts with their wings spread out wide. So, bending my flexible rule against reposts, I am updating a very old TUVU post with lots of new images and facts about this fascinating bird, which manages to be simultaneously majestic, hideous, revolting and socially vital, all packed into a single species…

turkey-vulture

The TUVU is a familiar sight flying over Abaco, wheeling effortlessly overhead on thermals or gliding with the wind in singles, pairs or flocks. Statistically, 83% of all photographs of turkey vultures are taken from below and look like this: 

Turkey Vulture, Abaco Bahamas (Bruce Hallett)

Of those, 57% are taken in unhelpful light, and look like the one below. On the positive side, this picture show the extreme delicacy of the wing-tip feathering that enables these birds to adjust their direction and speed (this is not the bird above; it was taken by someone else at a different time. But 100% of TUVU in-flight photos are indistinguishable).

Turkey Vulture Abaco Bahamas (Keith Salvesen)

TUVUs have a wide range in the Americas and the Caribbean, and can prosper in almost any type of habitat. This is probably because these large birds are almost exclusively carrion feeders, and carrion is everywhere. They spend their days scavenging, or thinking about scavenging. They do not generally kill live creatures.turkey-vulture

The word ‘vulture’ derives from the latin word ‘vulturus‘ meaning ‘ripper’, ‘shredder’, or in more recent times, ‘very loud Metallica song*‘. TUVUs have very good eyesight, and an acute sense of smell that enables them to detect the scent of decay (and consequent release of the chemical ethyl mercaptan) from some distance. A breeding pair will raise two chicks, which revoltingly are fed by the regurgitation of all the rank… excuse me a moment while I… I feel a little bit… ~~~~~~~~~~~ …alright, OK again now.

Turkey Vulture Abaco Bahamas (Keith Salvesen)

When they are not flying, feeding, breeding or feeding young, TUVUs like best to perch on a vantage point – a utility post is ideal. But unusually for a bird, you won’t ever hear them sing or call. They lack a SYRINX (the avian equivalent of a larynx), and their vocalisation is confined to grunting or hissing sounds. Here’s a hiss (at 10 / 15 secs).

These vultures are often seen in a spread-winged stance, which is believed to serve multiple functions that include drying the wings, warming the body, and baking bacteria. Possibly it also reduces the miasma of rotting meat that may surround them after a good meal.

Turkey Vulture Abaco Bahamas (Keith Salvesen)

Equally happy to spread their wings on the ground – a debris-strewn shoreline being idealTurkey Vulture, Abaco Bahamas (Clare Latimer)

10 SCAVENGED TURKEY VULTURE FACTS FOR YOU TO PICK OVER

  • One local name for TVs is ‘John Crow’
  • An adult  has a wingspan of  up to 6 feet
  • Sexes are identical in appearance, although the female is slightly larger
  • The eye has a single row of eyelashes on the upper lid and two on the lower lid
  • TVs live about 20 years. One named Nero had a confirmed age of 37 
  • LEUCISTIC (pale, often mistakenly called “albino”) variants are sometimes seen

Leucistic (white) Turkey Vulture, Florida Keys (amy-at-poweredbybirds)

  • The Turkey Vulture is gregarious and roosts in large community groups
  • The Turkey Vulture has few natural predators
  • Though elegant in flight, they are ungainly on the ground and in take-off
  • The nostrils are not divided by a septum, but are perforated; from the side one can see through the beak [some humans also suffer from MSS (missing septum syndrome). They tend to ‘sniff’ a lot]

Turkey Vulture headshot Wiki

REVOLTING CORNER / DEPT OF ‘WAY TOO MUCH INFORMATION’ 

SQUEAMISH? THEN LOOK AWAY NOW

UNATTRACTIVE HABITS The Turkey Vulture “often defecates on its own legs, using the evaporation of the water in the feces and/or urine to cool itself, a process known as UROHIDROSIS. This cools the blood vessels in the unfeathered tarsi and feet, and causes white uric acid to streak the legs”. The droppings produced by Turkey Vultures can harm or kill trees and other vegetation. Maybe don’t park your nice car under one of their perching posts…

Turkey Vulture with carrion (wiki)

HORRIBLE DEFENCES The main form of defence is “regurgitating semi-digested meat, a foul-smelling substance which deters most creatures intent on raiding a vulture nest. It will also sting if the predator is close enough to get the vomit in its face or eyes. In some cases, the vulture must rid its crop of a heavy, undigested meal in order to take flight to flee from a potential predator”

Turkey Vulture in flight, Abaco Bahamas (Charlie Skinner)

DIETARY NOTES TUVUs tend to prefer recently dead creatures, avoiding carcasses that have reached the point of putrefaction. They will occasionally resort to vegetable matter – plants and fruit (you could view this as their side-salad). They rarely, if ever, kill prey – vehicles do this for them, and you’ll often see them on roadsides feeding on roadkill. They also hang around water, feeding on dead fish or fish stranded in shallow water. 

ECO-USES If you did not have birds like this, your world would be a great deal smellier and less pleasant place, with higher chance of diseases from polluted water and bacterial spread. TUVUs kept the highways clear and work their way round the town dumps recycling noisome items. 

turkey-vulture

FORAGING TUVUs forage by smell, which is uncommon in birds. They fly low to the ground to pick up the scent of ethyl mercaptan, a gas produced by the beginnings of decay in dead animals. Their olfactory lobe in the brain is particularly large compared to that of other animals.

SEX TIPS Courtship rituals of the Turkey Vulture involve several individuals gathering in a circle, where they perform hopping movements around the perimeter of the circle with wings partially spread. In humans, similar occasions are called ‘Dances’. A pair will fly, with the female closely following the male while they flap & dive… then they land somewhere private and we draw the veil…

Turkey Vulture Abaco Bahamas (Keith Salvesen)

turkey_vulture2

My favourite graphic of all time

Credits: Nina Henry (1); Bruce Hallett (2); Keith Salvesen (3, 4, 5, 11); Clare Latimer (4, 6); amy-at-poweredbybirds (7);  Wiki, small pics 8, 9); Charlie Skinner (10); Craig Nash (12); Xeno-Canto / Alvaric (sound file); Info, magpie pickings; Birdorable (cartoon); RH (Keep Calm…); depressingnature.com (puking TUVU)

*As Metallica so appropriately wrote and sweatily sang (luckily there’s no verse referencing urination, defecation and puking). ALERT don’t actually play the video – the song hasn’t aged well! In fact… it’s terrible. Woe woe indeed…

The vultures come
See the vultures come for me
Fly around the sun
But now too late for me
Just sit and stare
Wait ’til I hit the ground
Little vultures tear
Little vultures tear at flesh

Warts and all… the gorgeous, hygienic, roadkill-ridding vulture, with a few dirty habitsTurkey Vulture Abaco Bahamas (Craig Nash)

A WHITER SHADE OF TAIL? LEUCISM IN BIRDS


Leucistic Turkey Vulture, Florida Keys 2 (Amy at PoweredbyBirds

Leucistic Turkey Vulture (Amy Evenstad, PoweredByBirds.com)

A WHITER SHADE OF TAIL? LEUCISM IN BIRDS

And not just the tail*. Other parts of a bird. Sometimes most of a bird. More rarely, an entire bird. Whichever, a bird affected by leucism stands out from the crowd – out of the ordinary and therefore startling to the eye. I’d be very surprised if the fine turkey vulture in the header image didn’t make you look twice – maybe even to check if some devious Rolling Harbour P/shop trickery had been at work. Yet it’s just a TV / TUVU in the Florida Keys, living a normal vulturine life.

kcac TUVU JPG

ABACO’S LATEST LEUCISTIC DISCOVERY

A leucistic Western Spindalis found within the past week on Abaco by Keith KempWestern Spindalis (leucistic) Abaco 2 (Keith Kemp)Western Spindalis (leucistic) Abaco 1 (Keith Kemp)

For comparison – the real dealWestern Spindalis BH IMG_1711 copy

LEUCISM? EXCUSE ME, AND THAT IS?

First, what it is not. It is not albinism, which results from diminished or lost melanin production that affects pigmentation. One characteristic of the condition is the tendency to pink eyes, which of course is seen in humans as well as animals and birds. Here’s an obvious yet totes adorbs illustration:

Albino Rabbit (pinterest)

Albino Fwuffy Bwunny Wabbit

WELL, WHAT IS IT THEN?

Put simply, melanin is only one of many ingredients of pigmentation. Leucism is caused through pigment loss involving many types of pigment, not just melanin. In birds this results in unnaturally light or white colouring of feathers that may be partial or entire. The eyes of a bird with leucism are unaffected. At one extreme, if all pigment cells fail, a white bird will result; at the other extreme, pigment defects cause patches and blotches of pale or white on the bird, often called a ‘pied’ effect. The condition can be inherited.

A mallard on Abaco. The species is known for its wide colour variations in both sexes. Sometimes the variations go beyond the usual range. This is a leucistic bird – though not, as it appears, one-legged.Leucistic Mallard, Abaco (Nina Henry)

A leucistic common gallinule (moorhen) on AbacoLeucistic Common Gallinule (Moorhen) Abaco (Tony Hepburn)

Leucistic rock pigeon800px-Leucistic_Rock_Pigeon

BAHAMA (WHITE-CHEEKED) PINTAIL: A PIGMENT PUZZLE

I have found more examples of leucism in the ‘Bahama Duck’ than any other local species. But there is also scope for confusion. First, here’s a pintail that is undoubtedly leucistic – note that the eyes and beak are unaffected by pigmentation deficiency:

Leucistic Bahama Pintail (Jim Edmonson)

But not all pale variants can be so confidently labelled. Here are two photos I took at the well-known birding pond on the Treasure Cay golf course [ask for permission at the club house first – it may, for example, be a match day]. In the first, bottom right, there is plainly an ‘odd’ pintail, silvery rather than ruddy brown (yes, I do see the coot in the pack as well). The second photo shows the same bird on dry land.

White-cheeked (Bahama) Pintail, Abaco 1 (Keith Salvesen) White-cheeked (Bahama) Pintail, Abaco 2 (Keith Salvesen)

This is known as a ‘silver pintail’. These are said to be a leuchistic variant, and they are stocked by poultry dealers as ornamental ducks at a higher price than the standard brown (and much-loved) version. However this bird clearly retains the essential markings of a normal pintail that you might expect to be absent (at least in patches) in the ‘true’ leucistic bird. I’ve seen it describes as a ‘gray morph’. I wonder where the line is drawn between a marked colour variant or morph in a bird; and an obviously pigment-abnormal, leucistic bird where incidence and extent of the condition seems to be random.

A fine example of a ‘pied’ American Robin, an occasional visiting species on Abaco

Leucistic American Robin (Amy @ PoweredbyBirds)

Leucistic American Robin (Amy Evenstad, PoweredByBirds.com)

PIPING PLOVERS CAN BE LEUCISTIC TOO

PIPL are my current bird preoccupation, but until I checked them out, I hadn’t imagined what a leucistic one would look like. I now have the answer… Leucistic Piping Plover (Audubon Alliance)leucistic plover 2leucistic plover 3

These photos of a leucistic female were featured by Audubon Alliance for Coastal Waterbirds, Audubon Connecticut. They were taken by Jim Panaccione, a Biological Science Technician at Parker River National Wildlife Refuge, Newburyport, Massachusetts in 2012. I hope he won’t mind their illustrative use here… Despite the theory that leucistic birds may find it hard to find a mate – and might even be attacked by its own species – this pair successfully nested in 2012.

I’d be interested to hear about other leucistic birds found on Abaco. Please add a comment or email me. Or upload a photo to the Rolling Harbour FB page if you like.

OPTIONAL MUSICAL & CULTURAL DIGRESSION

A WHITER SHADE OF PALE

*Obviously, it had to be ‘tail’ in the title to justify one of my clunky ‘jokes’ and an accompanying musical diversion. That’s just the way it is, I’m afraid. Bach’s well-known descending chord sequence of was of course shamelessly ripped off by ingeniously adapted by Procol Harum for ‘A Whiter Shade of Pale’, their first single in 1967. Relive a Summer of Love right here and now. Or for a change try a different version by Annie Lennox

Any fret-tweakers might like to see the sheet music of Bach’s Air for guitar – you could even play it on Air Guitar – which is relatively easy, being in C major. 

Air on a G String - J S Bach - Guitar Tab JPG

The best known commercial use of the tune was in the famed series of adverts that  equated a mild cigar called Hamlet with happiness, accompanied by an excerpt from a jazzy version of Bach’s ‘Air on the G String’. Here is one of the best – and possibly the only advert to my knowledge to feature not one, but two excellent Sir Walter Raleigh jokes. But the music never gets past the first familiar chord…

Credits: thanks to Amy Evenstad (PoweredByBirds.com) for use permission for her wonderful TUVU & AMRO photos; other photos by Keith Kemp & Bruce Hallett (Spindalis); Pinterest (rabbit); Nina Henry (mallard); Tony Hepburn (moorhen); Wiki (pigeon); Jim Edmonson (leucistic pintail); RH (silver pintail); Jim Panaccione / Audubon (piping plovers); Tip o’ the Hat to Birdorable (TV inset in my ‘keep calm’ mock-up): Procol Harum, esp. Robin Trower for building a great career ‘reminiscent’ of Hendrix; J.S. Bach for a nagging tune; Hamlet cigars for ingenuity & making me laugh