WTF? (WHAT’S THAT FISH): FLYING GURNARD

May 24, 2023 by Rolling Harbour

WTF? (WHAT’S THAT FISH) 10: FLYING GURNARD

Imagine that you are swimming along resplendent in your snorkelling gear (me) – or in scuba gear for the advanced swimmer (you). There, below you, camouflaged against the sea bottom is a fish. A strange-shaped brown sort of creature with odd side fins. As it progresses over the gravelly sand, your immediate reaction is ‘what the…?’ Its fins seem to be turning into… wings. Like this:

Flying Gurnard (Adam Rees / Scuba Works)

Yes, it’s a flying gurnard. Unlike flying fish, it can’t actually fly through the air. But once its wings are fully spread, it certainly looks as though it could.

Flying Gurnard (Adam Rees / Scuba Works)

WHAT’S THE POINT OF THE WINGS IF THE THING CAN’T FLY?

This gurnard species usually gets around using its ventral fins as ‘legs’, with the pectoral fins (‘wings’) close to the body. There seem to be several possible reasons for possessing the ‘sudden-deployment-of-flashy-wings’ superpower.

It surprises and deters predators by movement, turning prospective prey into an apparently different creature
Bright or lurid colouring may be a deterrent warning of a foul-tasting or poisonous species (APOSEMATISM)
A creature may actually be harmless and even tasty (as here) but may appear to be unpalateable or poisonous (BATESIAN MIMICRY)
In any event, the wings enable the fish to take off from the sea bottom and travel faster by ‘flying’ thought the water to escape a predator

Dactylopterus_volitans Flying Gurnard (cralize wiki)

I had a quick look to see how scientists in history had depicted this extraordinary fish. The earliest illustration I could find was taken from “Allgemeine Naturgeschichte der Fische (General natural history of fishes),” a 12-volume encyclopedia by author/illustrator Marcus Elieser Bloch (1723-1799), which described all fish species then known to science (and 267 previously unknown) (© AMNHD. Finnin) sourced from ‘Hyperallergic’
Flying Gurnard

Here’s a short video of a flying gurnard on the move, from ‘Sia Big Fish’

Credits: All main images Adam Rees / Scuba Works with many thanks, except final one ‘cralize wiki’; Hyperallergic for the historic image; Sia Big Fish for the video

Rolling Harbour / Keith Salvesen

ROYAL CORONATION TERNS

May 8, 2023 by Rolling Harbour

CORONATION

ONE ROYAL TURN DESERVES… AN ABACO ROYAL TERN

I wrote this post about Royal Terns Thalasseus maximus* quite some time ago, in the early days of Delphi (and indeed Rolling Harbour™ ® ). Bonefishing was a completely new experience and my skills were embryonic. As they continued to be for the duration. By then the amazing birdlife of Abaco had reeled me in and BIRDS OF ABACO was in the planning stage.

If there’s a magnificent golden bandwagon drawn by 8 horses passing by, why not just hop on? I’ve skipped the info about the range and nesting arrangements of these birds. Here are a few, in all their regal glory, posing in the sunshine on a dead tree way out on the Abaco Marls. The header image was taken on Cherokee Long Dock, long pre-Dorian and its magnificent replacement.

** Now to be renamed Thalasseus carolus rex magnificans. Not worldwide, obviously.

PS No terns were injured in trying to get the yellow crown to fit one of them

PINE WARBLERS ON ABACO: ‘PINUS ENVY’

April 20, 2023 by Rolling Harbour

PINE WARBLERS ON ABACO: ‘PINUS ENVY’

The Pine Warbler Setophaga pinus is one of 5 year-round resident warblers (endemics) on Abaco. All are to be admired, of course. The others are Bahama yellowthroat; Bahama warbler; olive-capped warbler; and yellow warbler.

The pine warbler is also to be envied for several reasons:

Like most Setophagae, they are bright, lively and attractive birds
Bahamas residents all year round – no long exhausting migration flights twice a year
Abaco has vast areas of their preferred pine forest habitat
They are plentiful – the population is largely untroubled by usual habitat concerns
They are one of the few seed-eating warbler species, so feeders are a bonus

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 of Abaco were once a vital local source of timber (SAWMILL SINK q.v.). As a historical note, felled pines were also exported to the UK to be made into the strong pit-props needed for coal-mines.

Immature

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

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 / pry out insects from the rough pine trunks and branches.

WHAT OF THEIR NIDIFICATION?

The pine forest is obviously the preferred nesting habitat for these birds. The warblers also nest in the smaller groups of pines found (for example) in or near some of the settlements; or in backcountry 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, a position that seems far less secure. One theory on pine warbler nest location is that they feel safer from predators by building at the end of a small branch*.

WHAT DO THEY SOUND LIKE?

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.

MUSICAL TRILL Paul Driver / Xeno Canto

SLURRED CHIP Don Jones / Xeno-Canto

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); Paul Driver / Xeno Canto – call; Don Jones / Xeno Canto – chips; Milton Harris – nesting theory

ROCK BEAUTY: BAHAMAS REEF FISH

April 7, 2023 by Rolling Harbour

ROCK BEAUTY . Holacanthus tricolor . BAHAMAS REEF FISH

These creatures are a small species of angelfish. Seen swimming around the reefs they are unmistakeable, not least because of their bright yellow hi-viz jackets, remarkable blue eyeliner and blue-black lipstick.

Rock Beauties look like prime candidates for anyone’s aquarium, but they have picky dietary requirements and a tendency for aggression that make them unsuitable (fortunately for them).

They are highly specialised feeders, needing marine sponges in their daily diet. They are also prone to chase tank-mates and nip them. On balance, they look more fetching nosing about the coral anyway.

WHAT DO JUVENILES LOOK LIKE?

Juvenile rock beauties are cute mini-versions of the adults, only even more yellow and with yellow lips.

In development stages, they may have a vivid blue and black circle in front of the tail fin…

… or a large dark patch on their sides

NOT A TRUE ‘ROCK BEAUTY’ (no offence, Lita)

A TRUE ROCK BEAUTY

Credits: Melinda Riger, Grand Bahama Scuba; WP

GREAT EGRETS: NOBLE (YET MISNAMED) HERONS

March 28, 2023 by Rolling Harbour

GREAT EGRETS: NOBLE (YET MISNAMED) HERONS

The Great Egret is actually a heron rather than an egret. It’s a Great Heron. All egrets are members of the heron family Ardeidae, but the converse is not true. As long ago as 1758, Linnaeus awarded the bird the binomial name Ardea alba i.e. ‘Heron white‘. Why it should have been so hard to stick to that authoritative nomenclature, I can’t imagine. Perhaps in time all heron and egret species became so hopelessly confusing for people that it ceased to matter much what they were called.

Maybe it was that type of carelessness that led to people from the mid-c19 onwards eyeing up GREGs as a source of hat feathers and other decorative necessities. As with flamingos and many other beautiful avian species, mankind’s millinery and other fashion needs were satisfied at the expense of gorgeous plumage. Actually, at the cost of the birds’ lives: they were simply shot in huge numbers.

Healthy populations were decimated; for some species they never recovered. For others, the great egret among them, the passage of time and the passing of fashions – backed in many cases with conservation programs – have successfully restored the populations. In 1953 the National Audubon Society, which was formed at least in part to discourage the killing of birds for their feathers, took a decisive step in the cause of the great egret by making the bird the emblem of the organisation.

Photo Credit: Nina Henry photographed all the egrets in this post. Her wonderful images of this magnificent ~~egret~~ heron made a significant contribution to the “BIRDS OF ABACO” project.

WTF? (WHAT’S THAT FISH): ‘GUITARFISH ROCK’

March 14, 2023 by Rolling Harbour

WTF? (WHAT’S THAT FISH): ‘GUITARFISH ROCK’

A spectacular entry in my WTF? series came courtesy of Adam Rees and a night dive in Florida waters: the guitarfish, (Gr: rhinos – nose; batis – ray) . Until I saw Adam’s photos, this creature was unknown to me. It sounded so improbable, and conjured up some nightmare piscine-based modification of a Strat, an instrument whose classic looks should not be meddled with without consequent loss of liberty.

Guitarfish, Florida (Adam Rees)

The guitarfish belongs to a family of rays, Rhinobatidae, of which there are many species worldwide. In some ways the fish looks like a crossover with a shark. Although they have a ‘ray face’ and small wings, there is also a sharklike appearance with its fins and a sharklike swimming action (see video, below). If you think there is a primitive or prehistoric look to the guitarfish, you’d be right. According to the temporal range chart they date from the late Jurassic era.

Guitarfish Temporal Range

I have been trying to nail the exact model of Adam’s finny Strat-ray. I am putting my money on the Atlantic guitarfish Rhinobatos lentiginosus, which may (or may not) be the same as the spotted or freckled; and is similar to the more widely photographed shovelnose guitarfish with its cute face. Not that I am very bothered: it’s the overall unusualness of Adam’s creature that really counts.

Shovelnose Guitarfish (ventral view) (Greg Hume wiki)

The strange thing is that although the guitarfish is a denizen of, for example, floridian, caribbean and mexican gulf waters, it is said to be unrecorded for the Bahamas. These bottom-feeding creatures inhabit shallower waters near coastlines and estuaries. They eat crabs, shellfish and worms – all in plentiful supply in Bahamas waters – so I can’t see a reason why they should not be found there. Perhaps they are seen but unreported. I have in mind the recent reports of SAWFISH and BATFISH. So kudos awaits the person who reports – with photo – the ‘first’ Bahamas guitarfish. Maybe there’s scope for a song about it!

GUITARFISH ‘LIVE’

Usually caught by mistake by anglers, or as bycatch by fishing vessels
Inedible (unless someone knows better…)
Non-aggressive and harmless to humans despite having a mouthful of small teeth
Swims like a shark – the tail has no spinal structure
Has a cute face (unlike a a shark)
Adults are about 30 inches long
They may bury themselves in sand or mud to ambush prey
They are viviparous, giving birth to live young that are born fully developed

As a postscript, it’s worth mentioning that on the same night dive, Adam also came across the uncommon batfish, a seriously prickly-looking starfish, and a spotted eagle ray. Worth losing sleep for.

. .

A similar kind of guitarfish, showing the very sharklike movements in the water

Credits: Adam Rees, with many thanks; Greg Hume; Johan Fredriksson wiki; magpie pickings, in particular Florida Museum of Natural History / Taylor Sullivan and the truthful parts of various Wiki articles

Guitarfish, Florida (Adam Rees)

‘STAR ANIS’ ON ABACO, BAHAMAS

February 26, 2023 by Rolling Harbour

Smooth-billed Ani, TCGC Hole 11 - Becky Marvil

‘PRESENTING… A LARGE BILL’

The Smooth-billed Ani (Crotophaga ani) is one of three members of the cuckoo family found on Abaco, the others being the MANGROVE CUCKOO and the YELLOW-BILLED CUCKOO. Anis range from Florida and the Bahamas in the north down through the Caribbean to South America, where they are widespread.

Smooth Billed Ani, Abaco - Nina Henry 2a

Unlike their shy and retiring cuckoo cousins, anis are extrovert shouty birds that like to hang out in noisy gangs and family groups. They can often be found in low scrub, bickering, squawking, and generally fluttering around in a disorderly way. You’ll probably hear them from some way off, sounding like this:

Anis have advanced social, parenting and chick-rearing skills. They build a communal nest for the group, and all share in egg incubation and chick-feeding duties They may raise up to three broods in a season, which keeps the numbers up. Rather touchingly, the young of earlier broods help to feed more recent chicks.

It follows from this that unlike many other cuckoo species, the ani is not a brood parasite. So the species does not lay its eggs in the nests of other, smaller birds which then unwittingly rear the interloper(s), who in turn push the legitimate hatchlings out of the nest and get all the food and attention.

Smooth-billed Anis Abaco - Gerlinde Taurer d

I have tried to discover why an ani’s beak is as it is, without much success. Very often beak shape relates directly to the feeding habits and preferences of a species, but it is hard to see how a diet consisting mainly of insects and small reptiles such as lizards would account for such a prominently protuberant proboscis. Here is a close-up of the item in question.

On Abaco (and indeed elsewhere) Anis are sometimes known as ‘Cemetery Birds’, no doubt because of their all-black appearance (though their raucous tendencies would be quite inappropriate for a graveyard). However although at a distance these birds may look completely black, catch one in the sun at the right angle, and you’ll find that the plumage is far more varied, and with some intricate patterning.

Smooth-billed Ani. Abaco Bahamas Tom Sheley

Look for Anis in low scrubland and coppice, cultivated areas, perched in unsteady noisy rows on utility lines, or foraging on the ground.

Smooth-billed Ani, Abaco. Gerlinde Taurer c

The appearance and flying abilities of Anis are wonders to behold. As I wrote in The Birds of Abaco, “Their curious heavy beaks, their clumsy flight and their untidy take-off and landing routines suggest a design fault”.

Smooth Billed Ani, Abaco - Nina Henry 1a

AIMEE MANN INTERLUDE **

“One… is the loneliest number…” Oh, hang on a moment… Smooth-billed Ani Abaco - Gerlinde Taurer a

…”two of us…standing solo in the sun…” Smooth-billed Ani, Abaco (Gerlinde Taurer) b

The Philatelic Bureau of the Bahamas Postal Service is commendably committed to featuring the natural history of the Bahamas. Although probably not in the top-ten of anyone’s bird list, the ani nevertheless got its own stamp in a 1991 bird issue.

As far as I know, there is not yet a collective noun for a group of anis. There should be. I put forward “A Commotion of Anis”

Smooth-biled Ani, Abaco - Bruce Hallett

DO NOT CONFUSE WITH STAR ANISE

images

Credits (all photos taken on Abaco): Becky Marvil, Nina Henry, Paul Harding, Gerlinde Taurer, Roselyn Pierce, Tom Sheley, Bruce Hallett, Keith Salvesen; sound files from Xeno Canto and FMNH; range map from IUCN; hat tip to the always excellent Aimee Mann. ** yes yes I know these aren’t her original songs but I like the AM versions a

s much

OSPREYS: ID GUIDE TO THE BAHAMAS SUBSPECIES

February 6, 2023 by Rolling Harbour

OSPREYS: ID GUIDE TO THE BAHAMAS SUBSPECIES

I have featured bird comparatives from time to time, not least because scope for confusion meant that I needed to investigate for my own peace of mind. These included the tyrant flycatchers; a number of superficially similar warbler species (mostly with yellow bits); varied vireos; all those heron-y / egret-y types and their disconcerting morphs (hello, white reddish egret).

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 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

In this Caribbean bird, below, 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

EXAMPLES OF P. h. carolinensis

EXAMPLES OF P. h. ridgwayi

THE EYES HAVE IT?

After I had looked into the noted distinctions I wrote “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 noticed that the eyes of the P.h.r were much paler compared with the bright orangey-yellow of P.h.c. This distinction is found in all the comparative photos above. The P.h.cs were photographed in Florida and further north and have the 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 haven’t seen this commented on since my original piece, but if anyone has a view it would be welcome.

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, with a small pocket camera in one hand and a rod in the other. 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.

ADDENDUM: Thanks to LSulikM for pointing out that female carolinensis (besides being larger than males) have frontal freckling, sometimes called a necklace, that is a prominent ID marker (see bottom image). Males may also have freckling but it is much less conspicuous. For ridgwayi the freckling is absent or (see the bird on the utility pole above) very sparse.

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). Thanks for all use permissions – also to Steve Connett for the idea! Original post in 2020.

BLUEHEAD WRASSE: PRIVATE LIFE LAID BARE

January 23, 2023 by Rolling Harbour

BLUEHEAD WRASSE: PRIVATE LIFE LAID BARE

The bluehead wrasse (or blue-headed wrasse) Thalassoma bifasciatum is a denizen of the coral reefs in the tropical waters of the western Atlantic Ocean. This bright little 4-inch fish is… a wrasse with a blue head. No more and no less. Unless it’s a juvenile. Then it is mainly bright yellow. It’s similar to BLUE TANG (aka ‘the Disney Dory’), which starts life bright yellow and grows up to be blue.

The species may be found singly, in pairs or small groups, or in schools. They have an important role to play in the life of the reef. They are CLEANER FISH, vital to the health and wellbeing of the larger species they attend to, and thus of the reef itself. This is ‘cleaning symbiosis’, a relationship of mutual benefit. The big fish get cleaned; the little fish have a useful function and – importantly for them – therefore don’t get eaten.

Having said that, blueheads are of course fair game as a snack for species that aren’t in the market for their cleaning services. Rather unfairly, some species that are quite content to let cleaner gobies pick around their gills and mouths are not so considerate of the wrasse (some types of grouper and moray eel, for example).

TELL US EXACTLY SEVEN BLUEHEAD WRASSE FACTS

Juveniles can alter the intensity of their colour, stripes & bars
The bluehead wrasse is a ‘protogynous sequential hermaphrodite’
All are born female**. Some change sex to male during maturation (see below)
Food includes zooplankton, small molluscs and small crustaceans…
…and parasites / other juicy bits (fungal growths, anyone?) from bigger fish
Main threats to the species are coral reef degradation / destruction and pollution
The bright colours invite aquarium use, but the trade in this species is not critical.

** Some sources suggest some are born male and remain male.

A juvenile bluehead – mostly yellow, with a pale underside

THE REMARKABLE SEX LIFE OF THE BLUEHEAD WRASSE

This is an unavoidable topic, I’m afraid. The bluehead’s sex life is the most interesting thing about them, and this is no time to be prudish. It has been the subject of extensive scientific research. As with many human relationships, “it’s complicated” but in a conch shell it boils down to this:

To recap, BWs are born female and as they mature, some become male.
Males reach an ‘initial phase’ when they can breed in groups with females
Some males grow larger & reach full colouration. This is the ‘terminal phase’
These large males aggressively chase away smaller ones & seek females to pair with
Their state of readiness is signalled by colour changes BUT the females know…
…that the smaller males have a sperm count higher than dominant males.

As the excellent organisation OCEANA puts it: Bluehead Wrasses may reproduce in four different ways throughout their lifetime: 1) as a female in a group spawning event; 2) as a female in a pair spawning event within the territory of a large male; 3) as a small male in a group spawning event; and 4) as a dominant, terminal male in a pair spawning event within its own territory.

A cropped still from a video I took at Fowl Cay marine reserve. I’ve looked at dozens of images online and not found one that was all blue with a yellow end to its tail fin. Perhaps it is just an all-blue alpha male.

Credits & Sources: Melinda Riger; Adam Rees; James St John; Oregon State edu / Pinterest; Wiki images; self; Oceana; IUCN; magpie pickings

FLAMINGO TONGUE SNAILS: DECORATIVE CORAL-DWELLERS

January 9, 2023 by Rolling Harbour

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. Whether alive or as shells, they are gratifyingly easy to identify. These snails live in the tropical waters of the Caribbean and the wider western Atlantic.

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.

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 protectively 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”. There’s more to them than that!

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 (a) startling in appearance and (b) on closer inspection by a predator, 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.

MANKIND’S CONTRIBUTION

It comes as little surprise to learn that man is 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 their allegedly dull shells Don’t be a collector; be a protector…

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

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

ABACO PARROT FOR A CHEERFUL YULETIDE & OPTIMISM FOR 2023

December 22, 2022 by Rolling Harbour

Thanks to all followers, likers, commenters, regular visitors, one-offs, local wildlife organisations, and friends of Rolling Harbour in general. This year we passed 1 million hits over the ten years of this blog. Proving that people love Abaco, the Bahamas, birds, marine mammals, manatees, reef fish, sharks, turtles, shore-life, shells, insects, plant life, bonefishing, lighthouses, local history, maps, conservation and a whole lot more; and are prepared to tolerate bad puns, haphazard presentation, and a less than rigourous scientific approach to it all.

Weirdest search term ever: How to dispose of dead bodies?

TUNICATES: SESSILE ASEXUAL SEA-SQUIRTS

December 19, 2022 by Rolling Harbour

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.

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

WHAT DOES ‘TUNICATE’ MEAN?

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

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.

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.

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

WRY ‘CUDA & SARDONIC SMILES, ABACO BAHAMAS

December 6, 2022 by Rolling Harbour

WRY ‘CUDA & SARDONIC SMILES, ABACO BAHAMAS

There’s no doubt about it, barracudas have a particularly unwelcoming look to them. They exude menace. There’s something about the torpedo shape, the primitive head, and the uncomfortably snaggle-toothed grin-with-underbite that suggests a creature not to be underestimated.

And that smiley mouth – rather scornful and derisive, is it not? A powerful creature in its element, where you are the intruder… and it sees it like that too. An adult barracuda may grow to nearly 6 foot long. Your are only temporarily of its world, and (it observes) you are keeping your distance.

The dental arrangements of a ‘cuda are a wonder in themselves. The teeth are razor sharp; an orthodontist’s nightmare because they are all different sizes and grow at different angles. Some are conventionally set in the jaws, but some actually grow from the roof of the mouth. There are ‘normal’ sized teeth interspersed with wicked-looking fangs that randomly grow facing forwards, backwards and sideways.

WHY THE UNTIDY MOUTH FURNITURE?

The name Barracuda is thought to derive from the Spanish word barraco meaning (in one of its senses) “overlapping teeth”. The jaws that contain the teeth are strong, and the underbite adds to the effectiveness of ‘cuda predation. Prey is highly unlikely to escape once caught. When the jaws snap shut, the sharp angled teeth – particularly the back-facing ones (cf fishhook barbs) prevent the victim from pulling away. Then the munching and shredding can begin inside what is essentially a perfectly equipped multi-bladed mincing machine.

Credits: Melinda Rogers / Dive Abaco except #3 & #8 Melinda Riger / Grand Bahama Scuba

Here’s looking at you…

MANATEE AWARENESS MONTH!

November 22, 2022 by Rolling Harbour

MANATEE AWARENESS MONTH: BAHAMAS? WE GOTTEM!

Manatees are apex ‘gorgeous marine mammals’. Gentle, inquisitive, brave, long-distance-but-rather-slow-swimming, grass-grazing miracle ur-elephant descendants. They never made it out of the sea in the Miocene epoch.

West Indian Manatee, Bahamas (BMMRO / Charlotte Dunn / Keith Salvesen)

Incongruous in a world of fast sharks, snappy ‘cudas, large whales and leaping dolphins, they contentedly mooch around the seagrass beds. No one in the world has ever objected to or dissed a manatee. They bring only delight to the sea-world, and offer only charm to mankind.

Manatee Awareness Graphic (Peppermint Narwhal)

In the past, I’ve written about the small number of manatees that inhabit the turquoise inner waters of the Bahamas. They were carefully recorded with individual identifying features – usually nicks in the paddle, or scarring. Usually they were named and, where possible, fitted with a tracker. Their friendships and amorous hook-ups were noted. Despite a 16-month birth cycle, manatee-lets were born. Then Dorian struck, and the situation for manatees (as with many other creatures) became unclear. The good news is that they are now increasingly sighted, with photos taken and soc med posts to admire.

IS THERE A DOWNSIDE FOR THESE APPARENTLY BLISSFUL AND PEACEFUL CREATURES?

Yes indeed. It’s mankind, I’m afraid. Among the threats to the survival of these unusual, endearing, and legally protected creatures are, in no particular order:

Pollution of inshore waters and canals
Degradation of the (formerly limitless) sea-grass beds where they feed
Reduction or tainting of the fresh water sources that they need to survive
Understandable over-enthusiasm by admirers – especially in harbours – in dousing them with water from hoses and feeding them lettuce…
…and similar behaviours that may lead to a trusting dependance on humans
Unthinking or speed-selfish boat behaviour in or near harbours resulting in collisions
Simply not caring at all and carving them up, leaving often deep prop-scars. Few manatees escape at least a few of these. Some do not survive.
Probably I don’t need to mention man-caused Global Warming, but I just have.

Let’s celebrate this special month for manatees. Let’s hope that they can survive and prosper in these increasingly difficult and dangerous times for almost all species. Look at any of these photos… can we agree that these wonderful animals deserve care and protection.

All photos: Charlotte Dunn / BMMRO and research contributors; final image ‘Save the Manatee’

A MURMURATION OF STARLINGS

November 14, 2022 by Rolling Harbour

*European Starling Sturnus vulgaris – High Line NYC* – RH

We are all familiar with some of the collective nouns for birds – flocks, flights, broods, maybe companies (parrots) and so on. There are plenty of lesser known terms for specific birds, of which quite a few seem rather remarkable: a wisdom of owls, a murder of crows, a lamentation of swans, an unkindness of ravens, an exaltation of larks. Most of these refer to perceived characteristics of a particular species (the swan pining for a lost mate – they pair for life). Some date from medieval times.

MURMURATIONS OF STARLINGS

In the UK in late autumn, starlings start to gather in huge flocks in trees and open fields. Twitchers begin to gather too, in their all-weather plumage, ready to watch the sensational avian displays of thousands and thousands of starlings as they take to the air almost simultaneously. They swirl in densely packed random formation, drawing complex patterns across the sky. The group will constantly change direction and height, sometimes splitting into subgroups and reforming. They may suddenly drop to the ground in a teeming raucous mass, before taking off again to continue the display.

It is sometimes possible to sense when the flight is about to begin, In a huge packed group on the ground, there is a hint of restlessness. There is movement. A few birds seem to jump slightly. Then in a flash they are away into the sky.

A brief encounter with a small murmuration last week

Murmuration, early evening, Maiden Castle, Dorset (an iron-age hill fort) – iPhone

Starlings Sturnus vulgaris are a European species. They are now common in North America, less so in the Bahamas. The non-European distribution happened this way: All the European Starlings in North America are descended from 100 birds set loose in New York’s Central Park in the early 1890s. The birds were intentionally released by a group who wanted America to have all the birds that Shakespeare ever mentioned.* In return, gray squirrels were introduced into Europe at about the same time, with the population increasing exponentially and displacing the indigenous red squirrel..

* All About Birds – Cornell Lab

Photos: Keith Salvesen, Bruce Hallett, Wiki Commons; Video Clip Keith Salvesen; Cartoon by the very excellent Birdorable

ABACO’S THREE CUCKOO SPECIES

November 1, 2022 by Rolling Harbour

Yellow billed cuckoo, Abaco Bahamas (Tom Sheley)

ABACO’S THREE CUCKOO SPECIES

There are 3 cuckoo species recorded for Abaco, all permanent residents. Two are relatively scarce; the third is the much-loved gregarious and raucous Ani. Recently I was contacted about a cuckoo seen on Man-O-War Cay. The photo revealed more of a glimpse than a sighting… but it clearly was not an all-black Ani. So here are the 3 species to admire in all their glory – and in the case of the first 2, to highlight the differences between them.

YELLOW-BILLED CUCKOO (and header image)

MANGROVE CUCKOO

SMOOTH-BILLED ANI

Photo Credits: Tom Sheley, Tony Hepburn, Alex Hughes, Gerlinde Taurer, Nina Henry

BLUE CHROMIS: A FLASH OF COLOUR ON THE REEF

October 25, 2022 by Rolling Harbour

BLUE CHROMIS: A FLASH OF COLOUR ON THE REEF

Larger reef fish tend to get more attention than the tiddlers, for obvious reasons. Yet a reef would not properly exist without the small fish that drift and wriggle round the corals. Blue chromis (Chromis cyaneus) are among the first reef fish species I ever met when snorkelling at Fowl Cays.*

Blue chromis belong to the same group as damselfishes. These unmistakeable, bright reef denizens are very visible despite their tiny size. These fish are shoalers, so out on the reef you can enjoy them flickering around you as you swim along or hang in the water to admire the corals.

Like many a pretty and easily captured small fish that can be monetised once removed from its natural home environment, the blue chromis is popular for aquariums. Humans like to keep them in their own home environments safely away from oceans and reefs, unselfishly feeding the little things concocted food to keep their little lives going till the cat gets them. [Sorry, I don’t know what came over me there]

Blue chromis are adaptable and sociable, and will happily swim with other small reef fishes (as above). My own favourite combo is chromis mixed in with sergeant majors. But a shoal of them (mostly) alone is pretty special too….

I cynically mentioned ‘concocted’ food earlier. Here is one online care instruction for looking after them: “They are omnivores, meaning that they eat both meaty and plant based foods. They are not difficult to feed and will eat a variety of regular aquarium fare, frozen, live, and sometimes even dry food. Feeding them a variety of foods will help them retain their color in captivity. They sometimes feed on the algae in the tank”. So I think it’s ok to suggest that leaving the fish out on the reef might suit them better.

If tempted to ‘rescue’ some from their reef habitat, rest assured that they have been known to spawn in captivity. Blue chromis can usually be obtained for about $10-15. And don’t hold back on the frozen food (though maybe warm it up a bit before feeding time). I rest my case.

*I say ‘snorkelling’ rather than anything more impressive because I am a pathetic swimmer and I know my limitations…

Credits: Melinda Rodgers / Dive Abaco; Melinda Riger / G B Scuba

CAPE MAY WARBLERS: SPECIAL SPECIES FOR GLOBAL BIRD WEEKEND 2022

October 8, 2022 by Rolling Harbour

CAPE MAY WARBLERS + WHAT’S IN A NAME?

The history of ornithological classification and nomenclature is littered with peculiarities. The attractive migratory Cape May Warbler Setophaga tigrina is a very good example of premature evaluation.

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 across the yellow band to (mainly) the Bahamas.

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 ever specimen of the species was collected on Cape May NJ by George Ord during an exploratory 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 bodies, from large down to tiny, were after all the only irrefutable evidence of a new ‘find’ at that time. Detailed drawings could be made and descriptions composed. The later display of the specimens enabled the expansion of ornithological knowledge and methodology, and brought consequent renown. The great Audubon took the research method *treading very carefully here* rather further than one might be comfortable with today, with somewhat indiscriminate use of lead shot.

As Wilson later wrote (note the words ‘beautiful little species, ‘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.

The odd (indeed ‘Ord’) thing was that the first-ever specimen was a complete one-off in that location at that time. Not a single sighting of the species (named Sylvia maritima by Wilson) was reported on Cape May or in that area for more than a century. Then at last in 1920, another example was found. Nowadays the CMW is not in the least unusual in the location that gave it its name.

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.

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 lively conversation (though you might want to try it out) but considering the multitude of warbler species in existence, the CMW has the benefit of a rather special adaptation.

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

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, which might help with ID. But then so do other warblers I’m afraid. Here’s something more practical – the tsi and the sip:

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).
Audubon Cartoon: On the Wings of the World; Grolleau & Royer / Nobrow (highly recommended)
Drawing, Nat Geo
Range map, Allaboutbirds / Cornell
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

CURLY-TAILED LIZARDS ON ABACO, BAHAMAS

September 27, 2022 by Rolling Harbour

CURLY-TAILED LIZARDS ON ABACO, BAHAMAS

The northern curly-tailed lizard Leiocephalus carinatus, to give it its full name, resembles a tiny dragon with a twist in the tail. These little critters bask in the sun, or scuttle away into holes and crevices as you approach them. I suspect that even a confirmed herpophobic would find some charm in them. They are, of course, completely harmless to humans.

Surprisingly, the Bahamas is home not just to one but five different curly-tail species, and nine sub-species. Broadly-speaking, the variants are found on different and specific islands and have discrete local markings. Mostly they are brownish, but they may also be grey or with a greenish tinge like this one I recently photographed.

Curly-tail males, being territorial, turn somewhat aggressive around breeding time, which is basically most the the year, from February to October. Behaviours indicative of their territorial claims include tail curling / uncurling (of course), head-bobbing, strutting about in an agitated way and inflating the sides of their necks in a threatening kind of way. The tiny-tails, 2″ long when born, are known as ‘hatchlings’.

An impressive poolside ‘double curly’

THREATS TO CURLY TAILS

According to the Bahamas National Trust BNT, the main dangers to the curly-tails of the Bahamas are:

Dogs, cats, rats and introduced predators such as raccoons
Collection for the pet trade – curly tails are unprotected by CITES listing (also cute)
Collection of the rarer endemics by reptile enthusiasts seeking ‘exotics’
Development and habitat destruction (though it is noted that curly tails seem to adjust quite well in developed areas)

A curly tails sloughs its skin as it grows, as with snakes and other reptiles

WHY THE CURLY TAIL?

As mentioned above, for use in territorial posturing
In courtship displays by males to attract females (luckily a method not available to humans)
As a response to predators, confusing an attacker with movement at both ends
As a last resort, to detach to aid escape (the tail re-grows)
For fun and just because they can grow one and you cannot

Credits: all photos, Keith Salvesen except #2 & #6, Charles Skinner; BNT

WORLD SHOREBIRDS DAY . COMPLETE CHECKLIST FOR ABACO, BAHAMAS

September 5, 2022 by Rolling Harbour

WORLD SHOREBIRDS DAY: ABACO’S COMPLETE CHECKLIST

Abaco’s birding records compiled for over 20 years include 33 shorebird species. For a few, the islands and cays are a permanent residence; for many others they are winter quarters; some species are visitors transient in their migrations; a few are rare vagrants. The complete checklist of Abaco’s shorebirds is below, along with 3 links to specific posts.

I have divided the species into 3 categories: sandpipers & kin; plovers; and a catch-all ‘large shorebird’ group that includes one or two sandpipers. Of the 26 birds featured and shown in the main checklist below, 23 are ones you might reasonably hope or expect to encounter on Abaco, though some only if you are lucky or your field-craft is excellent. The others are the long-billed dowitcher, American avocet and Wilson’s phalarope (of which only one has ever been seen on Abaco, with a photo to prove it). Many of these are showcased in my book The Birds of Abaco.

CLICK A LINK TO INVESTIGATE

LARGE SHOREBIRDS

SANDPIPERS

PLOVERS

THE COMPLETE CHECKLIST

The codes tell you, for any particular bird, when you may see it (P = permanent, WR = winter resident, TR = transient, V = vagrant); whether it breeds (B) on Abaco; and your chance of seeing it, graded from easy (1) to vanishingly unlikely (5).