Unknown's avatar

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 photoshop trickery had been at work. Yet it’s just a normal TUVU in the Florida Keys, living a normal vulturine life.

kcac TUVU JPG

LEUCISTIC DISCOVERY ON ABACO

A leucistic Western Spindalis discovered on Abaco by birder 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. Meet the perfect example…

Albino Rabbit (pinterest)

WELL, WHAT IS IT THEN?

Put simply(ish), 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

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 on Abaco. 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. In the first picture, bottom right, there is an obviously an ‘odd’ pintail, silvery rather than ruddy brown like the rest of them (and 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 much-loved standard brown 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 described as a ‘gray morph’. I wonder where the line is drawn between a noticeable colour variant or morph in a bird; and an obviously pigment-abnormal, leucistic bird where the incidence and extent of the condition seems to be random. I’d go with the morph idea.

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 one of my bird species preoccupations, but until I checked them out I hadn’t imagined what a leucistic one would look like, or whether they had ever been recorded. 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. 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.

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. And at 2.57 does he really sing  ‘….might as well’ve been toast…’?

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 and having no strings. 

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

‘BACH IN A MINUET’

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.

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); Keith Salvesen (silver pintail); Jim Panaccione / Audubon (piping plovers); Procol Harum, esp. Robin Trower for building a great career round being ‘reminiscent of Jimi Hendrix’; J.S. Bach for a nagging tune; Hamlet cigars for ingenuity & making me laugh

Unknown's avatar

“THE DIET OF WORMS”: WORM-EATING WARBLERS ON ABACO


worm-eating-warbler-bahama-palm-shores-abaco-bahamas-3-12-tom-sheley-small-copy

“THE DIET OF WORMS”: WORM-EATING WARBLERS ON ABACO

The little worm-eating warbler (Helmitheros vermivorum) is unique. Not because of its worm-eating propensities or its warbler-ishness (or the combination), but because it is the only species currently classified in the genus Helmitheros. The Swainson’s warbler was once in the same genus, but the WEWA saw off the competition.

Worm-eating Warbler, Man-o-War Cay Abaco (Charmaine Albury)

SO WHAT IS A HELMITHEROS THEN, IF IT’S SO SPECIAL?

The word is Greek, meaning something like ‘grub-hunter’. And the Latin-derived vermivorum reflects the diet of a VERMIVORE – an eater of worms. But this description is, like a worm, somewhat elastic. It includes caterpillars, larvae, grubs, spiders and similar creatures. But whereas there are other warbler vermivores there is only one Helmitheros.

worm-eating_warbler_Andy Reago & Chrissy McClarren wiki

SOME WORM-EATING FACTS TO DIGEST

  • WEWAs are sexually monomorphic. Males & females are indistinguishable for most of the year
  • They can only be reliably sexed at the height of the breeding season…
  • …don’t ask. OK, a magnifying glass may be needed
  • They are believed to eat actual earthworms quite rarely. Moth larvae are their best treat
  • They are ground-nesting birds, one of only 5 new-world warblers to do this
  • Like some shore-birds, adults may feign injury to lure predators away from the nest
  • They are vulnerable to nest parasitism by brown-headed cowbirds & feral cats
  • Fires, deforestation, habitat change & diminished food resources are all threats to the species
  • As are pesticides, which destroy the primary food source and are in any case potentially toxic

Worm-eating Warbler, Man-o-War Cay Abaco (Charmaine Albury)

DISTRIBUTION & CONSERVATION STATUS

The breeding range of the worm-eating warbler covers much of the eastern half of the US as far south as the Gulf Coast. It winters in the West Indies, Central America and southeastern Mexico. There is no overlap between summer and winter habitat. Because of the vulnerability of this ground-nesting species to a number of threats (see FACTS above), they are now IUCN listed as ‘Special Concern’ in New Jersey.389px-helmitheros_vermivorum_map-svg

worm-eating_warbler-tom-friedel-birdphotos-com-wiki

WHAT DO THEY SOUND LIKE?

In this case the song and call, as transposed into human, really does sound like the bird itself. The song is a rapid squeaky trill; and the calls for once do actually sound like ‘chip’ or ‘tseet’. See what you think (turn up the volume a bit).

Paul Marvin / Xeno-Canto

14352552_10209292869212511_2005172973387868491_o

THE (ORIGINAL) DIET OF WORMS – A DIGRESSION

Studied European history? Had a laugh over The Diet of Worms in 1521? This was an assembly (or ‘Diet’) of the Holy Roman Empire that took place in the City of Worms in Germany. There had already been several of them. This one resulted in an edict concerning Martin Luther and protestant reformation, with the consequence that… [sorry, I’ll spare you the details. I’ve started yawning already, just as I did at school I expect] 

worm-eating_warbler

It is always instructive to look at Audubon’s fine depictions from the early c19. Here is his WEWA. Notice that it is here called Sylvia vermivora. So he had the worm-eating part, but the first part of the name – referencing woods –  rather strangely relates to a group of old-world warblers. No, I’ve no idea why.

worm_eating_warbler_audubon-copy

Credits: Photos – Tom Sheley (1); Charmaine Albury (2, 4, 6); Andy Reago & Chrissy McClarren (3, 7); Tom Friedel (5). Research material – CWFNJ / Michael J Davenport; Tom Fegely / The Morning Call; assorted magpie pickings & open source

Unknown's avatar

LOGGERHEAD KINGBIRD: LORD OF THE FLIES


Loggerhead Kingbird, Sandy Point, Abaco Bahamas (Keith Salvesen)

LOGGERHEAD KINGBIRD: LORD OF THE FLIES

There are four main species of so-called ‘tyrant flycatchers’ (Tyrannidae) found on Abaco: the loggerhead kingbird, the gray kingbird, the La Sagra’s flycatcher and the Cuban pewee. Three are common permanent residents; the gray kingbird is a summer resident only. Several other flycatcher species are found on Abaco, but they are very uncommon winter residents, rare transients, or vagrants. 

Loggerhead Kingbird, Sandy Point, Abaco Bahamas (Keith Salvesen)

The loggerhead featured here became quite a good companion. Like other flycatchers – and indeed the cute little blue-gray gnatcatchers – loggerheads are curious and inquisitive birds, and relatively tame. One can get quite close without ruffling their feathers. 

Loggerhead Kingbird, Sandy Point, Abaco Bahamas (Keith Salvesen)

Loggerheads seem to have two methods of observing humans and their mysteries. One is by perching on a branch or in a shrub, watching intently. They stay quite still… until suddenly launching into the air to intercept some passing insect with their hooked beaks (so-called ‘hawking’), before returning to their perch. And staring at you again. The other method is to follow you round, either flying slightly ahead as you progress; or fluttering in the coppice alongside you; or playing catch-up from behind. 

Loggerhead Kingbird, Sandy Point, Abaco Bahamas (Keith Salvesen)

A typical quizzical loggerhead sideways look… all flycatchers do this

Loggerhead and gray kingbirds are similar in size, and can be quite easy to confuse. Top seasonal tip: because the grays are summer visitors only, it’s a fairly safe bet that any kingbirds seen between, say, October and April will be the resident loggerheads.

Loggerhead Kingbird, Sandy Point, Abaco Bahamas (Keith Salvesen)

MEMORABLE FACT TO DEPLOY IN CONVERSATION

The collective names for a group of kingbirds are: a Court, a Coronation, or (of course) a Tyranny

Loggerhead Kingbird, Sandy Point, Abaco Bahamas (Keith Salvesen)

Photo Credits: Keith Salvesen Abaco Bahamas; ‘Lordy’ the Loggerhead 

Unknown's avatar

ABACO’S 38 WARBLER SPECIES: AN ILLUSTRATED ID GUIDE


 

 

ABACO’S 38 WARBLERS: AN ILLUSTRATED ID GUIDE

The great winter migration of warblers and their arrival in The Bahamas is underway. Reports are appearing – the latest being the Northern Parula.  They will have made long journeys – hundreds of miles – and in the spring they will wing their way home for the summer. On Abaco, 38 warbler species are recorded for the main island and the cays, the latest being the first sighting of a Canada Warbler in 2018.  Since Dorian the situation has undoubtedly been different, especially with the transients and rare species. The 5 permanent resident warbler are still resident. Sighting records of the winter visitors have been scarce. Many migrants and transients have not been recorded since Dorian, and the rarest perhaps never will be. The hope must be that at least the most common winter warblers will continue to arrive, and in increasing numbers.

Yellow Warbler at sunrise.Abaco Bahamas.6.13.Tom Sheley copy copy

First-ever Canada Warbler for Abaco & the entire Bahamas: Aug 2018 (Chris Johnson)

Canada Warbler, Abaco Bahamas (1st record) (Chris Johnson)

Yellow Warbler at sunrise.Abaco Bahamas.6.13.Tom Sheley copy copy

This guide divides the 38 species into categories, with a code for each bird to show:

  • Resident status – permanent / breeding, migratory or transient
  • Frequency – likelihood of seeing each species in its season, rated from 1 (very likely) to 5 (extreme rarities, maybe recorded only once or twice since c1950 when recording began)
Bahama Warbler (endemic), Abaco Bahamas (Alex Hughes)

Bahama Warbler (endemic), Abaco Bahamas (Alex Hughes)

Numerically, the division breaks down into 3 categories of warbler:

  • 5 permanent residents (PR) that breed on Abaco (B), of which two are ENDEMIC
  • 21 winter residents (WR) ranging from ‘everyday’ species to extreme rarities like the very vulnerable Kirtland’s Warbler that needs a specific winter habitat that Abaco can provide 
  • 11 transients, most of which you will be very lucky to encounter
Palm Warbler, Abaco Bahamas (Nina Henry)

Palm Warbler, Abaco Bahamas (Nina Henry)

The photos that follow show an example of each warbler, where possible both (1) male and (2) taken on Abaco. Where I had no Abaco images – especially with the transients – I have used other mainstream birding resources and Wiki. All due credits at the foot of the post.

Bahama Yellowthroat, Abaco Bahamas (Gerlinde Taurer)

Bahama Yellowthroat, Abaco Bahamas (Gerlinde Taurer)

 

AN ILLUSTRATED GUIDE TO ABACO’S WARBLERS

Yellow Warbler at sunrise.Abaco Bahamas.6.13.Tom Sheley copy copy

5 PERMANENT RESIDENTS

BAHAMA YELLOWTHROAT Geothlypis rostrata PR B 1  ENDEMIC

Bahama Yellowthroat, Abaco (Charles Skinner)

BAHAMA WARBLER Setophaga flavescens PR B 1  ENDEMIC

Bahama Warbler - endemic Abaco Bahamas (Alex Hughes)

YELLOW WARBLER Setophaga petechia PR B 1

Yellow Warbler, sunrise, Abaco Bahamas (Tom Shelley)

OLIVE-CAPPED WARBLER Setophaga pityophila PR B 1 

Olive-capped Warbler, Abaco (Bruce Hallett)

PINE WARBLER Setophaga pinus PR B 1 

Yellow Warbler at sunrise.Abaco Bahamas.6.13.Tom Sheley copy copy

WINTER RESIDENTS  (COMMON)

OVENBIRD Seiurus aurocapilla WR 1 

OVENBIRD_Bahamas-Great Abaco_6639_Ovenbird_Gerlinde Taurer 2

WORM-EATING WARBLER Helmitheros vermivorum WR 2 

Worm-eating Warbler.Bahama Palm Shores.Abaco Bahamas.Tom Sheley

NORTHERN WATERTHRUSH  Parkesia noveboracensis WR 1 

BAHAMAS - Northern Waterthrush - Oct 2010 Becky Marvil

BLACK-AND-WHITE WARBLER Mniotilta varia WR 2 

Black & White Warbler, Abaco - Bruce Hallett

COMMON YELLOWTHROAT Geothlypis trichas WR 1 

Common Yellowthroat.Gilpin Pond.Abaco Bahamas.Tom Sheley copy

AMERICAN REDSTART  Setophaga ruticilla WR 1 

Bahamas-Great Abaco_6334_American Redstart_Gerlinde Taurer copy

CAPE MAY WARBLER Setophaga tigrina WR 1 

Cape May Warbler (m), Abaco - Bruce Hallett

NORTHERN PARULA Setophaga americana WR 1 

Northern Parula, Abaco - Woody Bracey

BLACK-THROATED BLUE WARBLER Setophaga caerulescens WR 2 

Black-throated Blue Warbler (m), Abaco - Bruce Hallett

PALM WARBLER  Setophaga palmarum WR 1 

Palm Warbler, Abaco - Peter Mantle

YELLOW-RUMPED WARBLER Setophaga coronata WR 2 

Yellow-rumped Warbler, Abaco - Keith Salvesen (RH)

YELLOW-THROATED WARBLER Setophaga dominica WR 1 

Yellow-throated Warbler, Abaco - Bruce Hallett

PRAIRIE WARBLER Setophaga discolor WR 1 

Bahamas-Great Abaco_6609_Prairie Warbler_Gerlinde Taurer copy 2

Yellow Warbler at sunrise.Abaco Bahamas.6.13.Tom Sheley copy copy

 WINTER RESIDENTS  (UNCOMMON TO RARE)

LOUISIANA WATERTHRUSH Parkesia motacilla WR 3 

Louisiana waterthrush William H. Majoros WIKI

BLUE-WINGED WARBLER Vermivora cyanoptera WR 3

Blue-winged Warbler, Abaco (Becky Marvil)

Blue-winged Warbler. talainsphotographyblog

SWAINSON’S WARBLER  Limnothlypis swainsonii WR 4 

Swainson's Warbler, Abaco - Bruce Hallett

NASHVILLE WARBLER Oreothlypis ruficapilla WR 4 

Nashville Warbler, Abaco - Bruce Hallett

HOODED WARBLER Setophaga citrina WR 3 

Hooded Warbler, Abaco Bahamas (Chris Johnson)

KIRTLAND’S WARBLER Setophaga kirtlandii WR 4 

Kirtland's Warbler (m), Abaco - Woody Bracey

MAGNOLIA WARBLER Setophaga magnolia WR 3 

Magnolia warbler, Abaco - Craig Nash

BLACK-THROATED GREEN WARBLER Setophaga virens WR 3 

Black-throated Green Warbler - talainsphotographyblog

Yellow Warbler at sunrise.Abaco Bahamas.6.13.Tom Sheley copy copy

TRANSIENTS

PROTHONOTARY WARBLER Protonotaria citrea TR 3 

Prothonotary Warbler, Abaco - Ann Capling

TENNESSEE WARBLER Oreothlypis peregrina TR 4 

Tennessee Warbler Jerry Oldenettel Wiki

ORANGE-CROWNED WARBLER  Oreothlypis celata TR 4 

Orange-crowned Warbler dominic sherony wiki

CONNECTICUT WARBLER Oporonis agilis TR 4 

Connecticut Warbler Central Park NYC 10000birds.com

KENTUCKY WARBLER Geothlypis formosa TR 4 

Kentucky_Warbler Steve Maslowski wiki - Version 2

BAY-BREASTED WARBLER Setophaga castanea TR 4 

Bay-breated warbler MDF Wiki

BLACKBURNIAN WARBLER Setophaga fusca TR 4

CHESTNUT-SIDED WARBLER Setophaga pensylvanica TR 4

Chestnut-sided Warbler talainsphotographyblog - Version 2

BLACKPOLL WARBLER Setophaga striata TR 3 

Blackpoll Warbler avibirds.com

WILSON’S WARBLER Cardellina pusilla TR 4 

Wilson's Warbler Michael Woodruff wiki

YELLOW-BREASTED CHAT Icteria virens TR 4 

Yellow-breasted Chat Emily Willoughby wiki

PHOTO CREDITS (1 – 37) Bruce Hallett (Header, 3, 9, 12, 14, 17, 21, 22); Tom Reed (1, 4); Cornell Lab (2); Tom Sheley (7, 10); Alex Hughes (5); Gerlinde Taurer (6, 11, 18);  Becky Marvil (8, 20a); Woody Bracey (13, 24); Peter Mantle (15); Keith Salvesen (16); William H. Majoros wiki (19); talainsphotographyblog (20b, 26, 34); Charmaine Albury (23); Craig Nash (25); Ann Capling (27); Jerry Oldenettel wiki (28); Dominic Sherony wiki (29); 10000birds (30); Steve Maslowski wiki (31);  MDF wiki (32, 33); Avibirds (35); Michael Woodruff wiki (36); Emily Willoughby wiki (37)

CHECKLIST based on the complete checklist and codes for Abaco devised by Tony White with Woody Bracey for “THE DELPHI CLUB GUIDE TO THE BIRDS OF ABACO” by Keith Salvesen