BAHAMA MOCKINGBIRD: RARE LEUCISTIC VARIANT ON ABACO


Leucistic Bahama Mockingbird, Abaco Bahamas (Keith Kemp)

BAHAMA MOCKINGBIRD

RARE LEUCISTIC VARIANT ON ABACO

The header image is of a Bahama mockingbird recently photographed by keen-eyed Abaco birder Keith Kemp. It is a thing of wonder and beauty, exceptionally rare and possibly unique. I can find no other example of a leucistic bird of this species online.

This is not Keith’s first leucistic bird discovery on Abaco either – a while back he found a leucistic Western spindalis. You can read more about leucism and its distinction from albinism, and see a number of other examples of leucism including a white turkey vulture HERE

Leucistic & Normal Bahama Mockingbird, Abaco Bahamas (Keith Kemp)

Even more astonishingly, Keith managed to get a photo of the ‘white’ bird and a ‘normal’ bird together (above). The difference is startling. Below is a fine photo by Peter Mantle of a Bahama mockingbird, as you would expect to see one – basically brown with a pale, flecked front / underside.

Bahama Mockingbird, Abaco Bahamas (Peter Mantle)

LEUCISM? EXCUSE ME, AND THAT IS?

I’ll recap what I wrote in the earlier post linked above. 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. For example:

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 by pigment loss involving many types of pigment, not just melanin. In birds this results in unnaturally pale or white colouring of feathers that may be partial or entire. The eyes of a bird with leucism are unaffected – so, not pink. 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.

KK’s leucistic Western spindalis, an example of partial or ‘pied’ leucism

Leucistic Western Spindalis, Abaco Bahamas (Keith Kemp) Leucistic Western Spindalis, Abaco Bahamas (Keith Kemp)

So there you have it: another extreme rarity for Abaco, and a further example of how rewarding – and surprising – birding on Abaco can be. To repeat the link to the more detailed article on leucism in birds, you can find with (*distraction alert*) some music and inappositely comedic material thrown in HERE

All photos Keith Kemp except the ‘normal’ bird, Peter Mantle

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