CAPE MAY WARBLER FOR MAY: WHAT’S IN A NAME?


Cape May Warbler, Abaco Bahamas (Charmaine Albury)

CAPE MAY WARBLER FOR MAY: WHAT’S IN A NAME?

The history of ornithological classification and nomenclature is littered with peculiarities, of which the attractive Cape May Warbler Setophaga tigrina provides a good example. And May is obviously the perfect month to feature this little bird.

The range of the species is well defined. In the summer the birds live within a broad band that straddles northern USA and Canada. In the winter they head south with all their migratory warbler cousins. Again, the target area is in a quite specific range.

As with all migratory species, some birds each year will wander or be blown off-course; or will take a rest stop en route and decide to stick around. And so it was that in May 1812, a month before the Battle of Waterloo, the first specimen of the species was collected on Cape May by George Ord during a trip with naturalist ALEXANDER WILSON (he of plover & snipe fame). To be specific, they had gone to shoot the birds they wanted to collect; the little bodies were after all the only irrefutable evidence of a new ‘find’ at that time.

Cape May Warbler, Abaco Bahamas (Bruce Hallett)

As Wilson later wrote (and note his use of the words ‘shooting excursion’ and ‘ransacked’)

THIS new and beautiful little species was discovered in a maple swamp, in Cape May county, not far from the coast, by Mr. George Ord of this city, who accompanied me on a shooting excursion to that quarter in the month of May last…The same swamp that furnished us with this elegant little stranger, and indeed several miles around it, were ransacked by us both for another specimen of the same; but without success. Fortunately it proved to be a male, and being in excellent plumage, enabled me to preserve a faithful portrait of the original.

Cape May Warbler, Abaco Bahamas (Sandy Walker)

The odd (indeed ‘Ord’) thing was that the specimen was a complete one-off at that time. With the benefit of hindsight, I think we can say it came in the category of ‘rare vagrant’: no other specimen of this species (named Sylvia maritima by Wilson) was seen on Cape May for more than a century… Then in 1920, another example was found. Over the succeeding years sightings have gradually increased, and the CMW is no longer regarded as unusual in the location that gave it its name. It has become an uncommon migrant instead.

Cape May Warbler, Abaco Bahamas (Sandy Walker)

On Abaco, CMWs are classified as WR1, which is to say common winter residents. Males have striking chestnut cheeks in the breeding season, with strong streaking on the underside. Note also the black eyestripe. Females and juveniles are paler and the marking is less prominent. These warblers are insectivorous; in winter they may also feed on nectar and fruit. Behaviour-wise, they have aggressive tendencies in defence of their territory and of their food sources. 

Cape May Warbler, Abaco Bahamas (Becky Marvil)

In researching this post, I discovered a strange (but slightly dull) fact. The CMW is unique among warblers in having a tubular tongue to enable nectar feeding (as with hummingbirds). This random fact hardly has the makings of a chat-up line, I do realise, but considering the multitude of warbler species in existence, the CMW has the benefit of a rather special adaptation. It’s one that Darwin himself might rightly be proud to have observed.

Tongue 2 (bottom left) is the CMW; No.5 is a bananaquit’s feathery tongue

Cape May Warbler, Abaco Bahamas (Bruce Hallett)

WHAT SHOULD I LISTEN OUT FOR?

Unhelpfully, even the authorities have a tough time describing the song and call of a CMW. As with so many song-birds, variations on the theme “the song is a simple repetition of high tsi notes; the call is a thin sip” are the best you can hope for. However, it’s worth noting that the species generally prefers to sing from high perches. But then so do many others I’m afraid. Here’s something more practical  – the tsi and the sip:

Cape May Warbler, Abaco Bahamas (Sandy Walker)

ALL BIRDS, EXCEPT THE LAST, PHOTOGRAPHED ON ABACO, BAHAMAS

  • Photo Credits: Charmaine Albury [from The Birds of Abaco] (1); Bruce Hallett (2, 6); Sandy Walker (3, 4, 7); Becky Marvil (5); Danny Sauvageau (8).
  • Drawing, Nat Geo
  • Range map, Wiki.
  • Audio clips Martin St-Michel / Xeno-Canto;
  • Research refs include, with thanks, American Ornithological Society / Bob Montgomerie (Queen’s University); Camino Travel Costa Rica / OS

Cape May Warbler (Danny Sauvageau)

OSPREY ID GUIDE: THE BAHAMAS SUBSPECIES REVISITED


Osprey, Abaco Bahamas (Tom Sheley)

OSPREY ID GUIDE: THE BAHAMAS SUBSPECIES REVISITED

I am reposting this article in the wake of a recent Bird Club of New Providence bird of prey ID query featuring distant but still helpful photos that enabled the ID as an osprey. As far as I can tell from the visible evidence (the images pixellate when enlarged) this is the ‘local’ Bahamian subspecies that differs in subtle ways from the standard North American version. Both types are found in the northern Bahamas; it would definitely be a great ‘get’ to locate one of each on the same day…

I sometimes feature bird comparatives, not least because there is so much scope for confusion that I have to keep checking for myself. Tyrant flycatchers; a number of superficially similar warbler species (all with yellow bits); those vireos; all those heron-y / egret-y types and their disconcerting morphs (hello, white reddish egret).

Osprey P.h.carolinensis (CWFNJ)

And so to the magnificent osprey Pandion haliaetus. This time, the comparison is between two subspecies, broadly the North American P. h. carolinensis and the Caribbean P.h. ridgwayi. There is some overlap in Florida, and some evidence of interbreeding. In the northern Bahamas in particular there is also an overlap, so an osprey seen on Abaco could be either variety. You’ll probably be too excited watching it to care much which type it is, but this article will help you if you do…

The two ospreys shown below were recently photographed at Spanish Wells, Eleuthera by Barbara Crouchley. This is a ‘bingo’ photographic scoop, because each type of bird was found in the same region; now we can check out the differences between the two birds. 

The first is a North American bird. Note in particular its distinctive eye mask, and the clearly marked upper breast, more so in the female than the male (which may even be white). The overall impression of the upper-parts is dark brown. They are slightly larger than their cousins in the south.

Osprey P.h. Carolinensis, Eleuthera Bahama (Barbara Crouchley)

Osprey P.h. carolinensis

In this Caribbean bird with its trophy fish, the eye-mask is absent, and the facial / nape markings are less pronounced. Furthermore, the breast and under-parts are white in both sexes (though slight marking may be apparent in some birds). And  the impression is of lighter upper-parts, even allowing for variable lighting and distance when the photos were taken. Conveniently, there’s not much detectable difference between male and females in the respective populations.

Osprey P.h. Ridgwayi, Eleuthera Bahama (Barbara Crouchley)

Osprey P.h. ridgwayi

EXAMPLES OF P. h. carolinensis

Osprey P.h. Carolinensis, Florida (Danny Sauvageau)Osprey P.h. Carolinensis, Florida (Danny Sauvageau)Osprey P.h. Carolinensis, Florida (Danny Sauvageau)

EXAMPLES OF P. h. ridgwayi

Osprey P.h. ridgwayi, Grand Bahama (Linda Barry Cooper)Osprey P.h. ridgwayi, Abaco (Jim Todd)Osprey P.h. ridgwayi, Abaco (Woody Bracey)

I’m going to stick my neck out here – I’ve not seen this mentioned anywhere, and I need to do some more comparative research. When I saw Barbara’s pair of photos, I immediately noticed that the eyes of the P.h.r were paler than the bright orangey-yellow of P.h.c. This distinction carries on through the comparative photos above: the P.h.cs were photographed in Florida and further north and have strikingly vivid eyes. The P.h.rs were photographed on Abaco and Grand Bahama at different times by different people. All have noticeably paler irises, more a light greeny-yellow. 

I’d welcome any views on this rash amateur theory. Preferably supportive ones…

UNDERWING DIFFERENCES

There’s a further comparison that can be made with the two subspecies in flight. Without going into technical and linguistic detail, the underwings of the P.h.cs are much darker than the Bahamas birds, whereas P.h.rs are notably paler and in some cases mostly white.  As an example, below is a distance shot I took when bonefishing out on the Abaco Marls, using a pocket camera. This is definitely a local bird! Compare with the dramatic image below it, where the strong darker markings are all too evident. It’s a great shot with which to bring the lesson to an end.

Osprey P.h. ridgwayi, Abaco Marls (Keith Salvesen)

Osprey in flight with fish (Northside Jim)

Photo credits: Tom Sheley (1); CWFNJ (2); Barbara Crouchley (3, 4); Danny Sauvageau (5, 6, 7); Jim Todd (8); Linda Barry Cooper (9); Woody Bracey (10); Keith Salvesen (11); the inimitable Northside Jim (12); Cute-toon, Birdorable. Thanks for all use permissions – also to Steve Connett for the idea!

LOGGERHEAD KINGBIRD: LORD OF THE FLIES


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

LOGGERHEAD KINGBIRD: LORD OF THE FLIES

Four principal so-called ‘tyrant flycatchers’ (Tyrannidae) are found on Abaco: the loggerhead kingbird, the gray kingbird, the La Sagra’s flycatcher and the Cuban pewee. These are common permanent residents, except for the gray kingbird which 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 when I was staying in Sandy Point recently. Like other flycatchers – and indeed the cute little blue-gray gnatcatchers – loggerheads are curious and inquisitive.

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 a Tyranny

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

Photo Credits: Keith Salvesen at Sandy Point, Abaco Bahamas; ‘Lordy’ the Loggerhead

PINE WARBLERS ON ABACO: PINUS ENVY


Pine Warbler, Abaco Bahamas (Bruce Hallett)

PINE WARBLERS ON ABACO: PINUS ENVY

The Pine Warbler Setophaga pinus is one of 5 year-round resident warblers on Abaco. The other 33 warbler species (including the recently recorded CANADA WARBLER) are migratory and at this time of year they will be in their summer breeding grounds. The co-resident warblers are the 2 endemics – Bahama warbler and Bahama Yellowthroat – plus the olive-capped warbler and the yellow warbler. You can see all 5 HERE. All are to be envied. First, they are all bright, attractive birds. Secondly, they live in the Bahamas all year round, without needing to undertake a long exhausting flight twice a year, unlike the rest of their warbler compadres. And indeed, unlike many of the human inhabitants of Abaco.

Pine Warbler, Abaco Bahamas (Alex Hughes)

As the name strongly hints, the pine warbler is primarily a bird of the pine forests, of which Abaco has an abundance. The tall, straight trees were a vital local source of timber (cf SAWMILL SINK). As a historical note, felled pines were also exported to the UK to be made into the strong pit-props needed for coal-mines. 

Pine Warbler (immature), Abaco Bahamas (Bruce Hallett)

Q. WHAT IS THE NORMAL RANGE OF THIS BIRD? A. THIS IS!

Pine Warbler, Abaco Bahamas (Tom Reed)

Pine warblers have a broad diet and forage methodically. Pine cones are a fertile source for food,  and those robust, stabby, slightly down-curved beaks are ideal for getting the seeds out of the cones. Equally, these warblers use their beaks to prise out insects from the rough pine trunks and branches.

Pine Warbler, Abaco Bahamas (Tom Sheley)

WHAT OF THEIR NIDIFICATION?

The pine forest is obviously the preferred nesting habitat for these birds. On Abaco there are vast acres of forest, but I’m sure the warblers also nest in the smaller groups of pines found (for example) in or near some of the settlements; or around the edges of former sugar cane fields and the like. One nesting habit is slightly unusual – pine warblers tend to build their nests near the end of branches rather than near the trunk. I have no idea why – the trunk end of a branch looks far more secure **.

Pine Warbler (immature), Abaco Bahamas (Bruce Hallett)

DO YOU HAVE ANY ‘FUN FACTS’?

  • One source states that “The song of this bird is a musical trill. Their calls are slurred chips. I think we’ve all been there at some time, possibly when lunching at Pete’s Pub.

SLURRED CHIP Don Jones / Xeno-Canto

  • The longest pine in the world is the Benzodiazepine (14 letters)

** Milton Harris helpfully points out: “One theory on Pine Warbler nest location is that they are safer from predators by building at the end of a small branch.  Some other birds do the same.”

Photo Credits: Bruce Hallett (1, 3, 6); Alex Hughes (2); Tom Reed (4); Tom Sheley (5); Dick Daniels (7); Wiki (range map); Nat Geo (species drawings)

Pine Warbler (Dick Daniels wiki)

FLAMINGO TONGUE SNAILS: DECORATIVE CORAL-DWELLERS


Flamingo Tongue Snails (Melinda Rogers, Dive Abaco, Bahamas)

FLAMINGO TONGUE SNAILS: DECORATIVE CORAL-DWELLERS

FLAMINGO TONGUE SNAILS Cyphoma gibbous are small marine gastropod molluscs related to cowries. The living animal is brightly coloured and strikingly patterned, but that colour only exists in the ‘live’ parts – the so-called ‘mantle’. The shell itself is usually pale, and characterised by a thick ridge round the middle. These snails live in the tropical waters of the Caribbean and the wider western Atlantic. Whether alive or dead, they are gratifyingly easy to identify.

Flamingo Tongue Snails (Melinda Rogers, Dive Abaco, Bahamas)

THE IMPORTANCE OF CORAL

Flamingo tongue snails feed by browsing on soft corals. Often, they will leave tracks behind them on the coral stems as they forage (see image below). But corals are not only food – they provide the ideal sites for the creature’s breeding cycle.

Flamingo Tongue Snails (Dive Abaco, Bahamas)Flamingo Tongue Snails (Melinda Rogers, Dive Abaco, Bahamas)

Adult females attach eggs to coral which they have recently fed upon. About 10 days later, the larvae hatch. They eventually settle onto other gorgonian corals such as Sea Fans. Juveniles tend to live on the underside of coral branches, while adults are far more visible and mobile. Where the snail leaves a feeding scar, the corals can regrow the polyps, and therefore the snail’s feeding preference is generally not harmful to the coral.

The principal purpose of the patterned mantle of tissue over the shell is to act as the creature’s breathing apparatus. The tissue absorbs oxygen and releases carbon dioxide. As it has been (unkindly?) described, the mantle is “basically their lungs, stretched out over their rather boring-looking shell”

Flamingo Tongue Snails (Melinda Rogers, Dive Abaco, Bahamas)

THREATS AND DEFENCE

The species, once common, is becoming rarer. The natural predators include hogfish, pufferfish and spiny lobsters, though the spotted mantle provides some defence by being rather unpalatable. Gorgonian corals contain natural toxins, and instead of secreting these after feeding, the snail stores them. This supplements the defence provided by its APOSEMATIC COLORATION, the vivid colour and /or pattern warning sign to predators found in many animal species.

Flamingo Tongue Snails (Melinda Rogers, Dive Abaco, Bahamas)

MANKIND’S CONTRIBUTION

It comes as little surprise to learn that man is now considered to be the greatest menace to these little creatures, and the reason for their significant decline in numbers. The threat comes from snorkelers and divers who mistakenly / ignorantly think that the colour of the mantle is the actual shell of the animal, collect up a whole bunch from the reef, and in due course are left with… dead snails and “boring-looking shells” (see photos below). Don’t be a collector; be a protector…

Flamingo Tongue Snails (Melinda Rogers, Dive Abaco, Bahamas)

The photos below are of nude flamingo tongue shells from the Delphi Club Collection. Until I read the ‘boring-looking shell’ comment, I believed everyone thought they were rather lovely… I did, anyway. You decide!

Flamingo Tongue Snail Shell, Keith Salvesen AbacoFlamingo Tongue Snail Shell, Keith Salvesen Abaco

Image Credits:  Melinda Rogers / Dive Abaco; Keith Salvesen / Rolling Harbour

Flamingo Tongue Snails (Melinda Rogers, Dive Abaco, Bahamas)

HERMIT CRABS: SHELL-DWELLERS WITH MOBILE HOMES


Hermit Crab, Abaco Bahamas (Keith Salvesen / Rolling Harbour)

HERMIT CRABS: SHELL-DWELLERS WITH MOBILE HOMES

As everyone knows, Hermit Crabs get their name from the fact that from an early age they borrow empty seashells to live in. As they grow they trade up to a bigger one, leaving their previous home for a smaller crab to move into. It’s a benign** chain of recycling that the original gastropod occupant would no doubt approve of, were it still alive… The crabs are able to adapt their flexible bodies to their chosen shell. Mostly they are to be found in weathered (‘heritage’) rather than newly-empty shells for their home. [**except for fighting over shells] 

Hermit Crab, Abaco Bahamas (Keith Salvesen / Rolling Harbour)

 HERMIT CRAB FACTS TO ENLIVEN YOUR CONVERSATION

  • The crabs are mainly terrestrial, and make their homes in empty gastropod shells
  • Their bodies are soft, making them vulnerable to predation and heat.
  • They are basically naked – the shells protect their bodies & conceal them from predators
  • In that way they differ from other crab species that have hard ‘calcified’ shells / carapaces
  • Ideally the shell should be the right size to retract into completely, with no bits on display

Hermit Crab, Abaco Bahamas (Keith Salvesen / Rolling Harbour)

  • As they grow larger, they have to move into larger and larger shells to hide in
  • As the video below shows wonderfully, they may form queues and upsize in turns
  • Occasionally they make a housing mistake and chose a different home, eg a small tin

Hermit Crab, Abaco Bahamas (Keith Salvesen / Rolling Harbour)

  • The crabs may congregate in large groups which scatter rapidly when they sense danger
  • The demand for suitable shells can be competitive and the cause of inter-crab battles
  • Sometimes two or more will gang up on a rival to prevent its move to a particular shell

HERMIT CRABS CAN EVEN CLIMB TREES – WITH THEIR SHELLS ON TOO

Hermit Crab, Abaco Bahamas (Tom Sheley)

HERMIT CRABS EXCHANGING HOMES with DAVID ATTENBOROUGH

This is a short (c 4 mins) extract from BBC Earth, with David Attenborough explaining about the lives and habits of these little crabs with his usual authoritative care and precision . If you have the time I highly recommend taking a look.

Credits: All photos taken on Abaco by Keith Salvesen except for the tree-climber crab photographed by Tom Sheley; video from BBC Earth

Hermit Crab, Abaco Bahamas (Keith Salvesen / Rolling Harbour)

TUNICATES: SESSILE ASEXUAL SEA-SQUIRTS


Painted Tunicates Bahamas (Melinda Riger / GB Scuba)

TUNICATES: SESSILE ASEXUAL SEA-SQUIRTS

Painted Tunicates Clavina picta are one of several species of tunicate ‘sea-squirts’ found in Bahamas and Caribbean waters. These creatures with their translucent bodies are usually found clustered together, sometimes in very large groups. One reason for this is that they are ‘sessile’, unable to move from where they have taken root on the coral.

Painted Tunicates Bahamas (Melinda Riger / GB Scuba)

HOW DO THEY FEED?

Like most if not all sea squirts, tunicates are filter feeders. Their structure is simple, and enables them to draw water into their body cavity. In fact they have 2 openings, an ‘oral siphon’ to suck in water; and an exit called the ‘atrial siphon’. Tiny particles of food (e.g. plankton) are separated internally from the water by means of a tiny organ (‘branchial basket’) like a sieve. The water is then expelled. 

Diagram of adult solitary tunicate

Painted Tunicates Bahamas (Melinda Riger / GB Scuba)

WHAT DOES ‘TUNICATE’ MEAN?

The creatures have a flexible protective covering referred to as a ‘tunic’. ‘Coveringates’ didn’t really work as a name, so the tunic aspect became the name. 

Painted Tunicates Bahamas (Melinda Riger / GB Scuba)

IF THEY CAN’T MOVE, HOW DO THEY… (erm…) REPRODUCE?

Tunicates are broadly speaking asexual. Once a colony has become attached to corals or sponges, they are able to ‘bud’, ie to produce clones to join the colony. These are like tiny tadpoles and their first task is to settle and attach themselves to something suitable – for life – using a sticky secretion. Apparently they do this head first, then in effect turn themselves upside down as they develop the internal bits and pieces they need for adult life. The colony grows because (*speculation alert*) the most obvious place for the ‘tadpoles’ to take root is presumably in the immediate area they were formed.

 

Painted Tunicates Bahamas (Melinda Riger / GB Scuba)

APART FROM BEING STATIONARY & ASEXUAL, ANY OTHER ATTRIBUTES?

Some types of tunicate contain particular chemicals that are related to those used to combat some forms of cancer and a number of viruses. So they have a potential use in medical treatments, in particular in helping to repair tissue damage.

Painted Tunicates Bahamas (Melinda Riger / GB Scuba)

Credits: all fabulous close-up shots by Melinda Riger / Grand Bahama Scuba; diagram from depts.washington.edu; magpie pickings with a particular mention of an article by Sara MacSorley

Painted Tunicates Bahamas (Melinda Riger / GB Scuba)