ENDANGERED SPECIES, ABACO (3): NASSAU GROUPER


Nassau Grouper (Melinda Riger / G B Scuba)

ENDANGERED SPECIES, ABACO (3): NASSAU GROUPER

The Nassau grouper Epinephelus striatus is one of a number of grouper species found in Bahamian waters. Of these, only the Nassau grouper is on the IUCN Red List, as Critically Endangered. When I last wrote about them they were in the lesser category ‘Threatened’.

Nassau Grouper (Melinda Riger / G B Scuba

In order to sustain a viable population, it is vital to maintain numbers and preferably to increase them year on year. Once it became clear that year-round commercial overfishing was a prime component of the steep decline in the population, a 3-month closed season during the breeding period was imposed. This has ensured that at the most critical time in the lifecycle of the species, the groupers are left alone to breed in peace and to perpetuate their species.

Nassau Grouper (Melinda Riger / G B Scuba)

The closed season operates from December to February to maximise the chances of breeding success. As with some other fish species, reproduction occurs around the full moon. The fish gather at spawning sites and the process is at its height around sunset.

Nassau Grouper (Melinda Rogers / Dive Abaco)

10 CONVENIENTLY COLLECTED NASSAU GROUPER FACTS

  • An adult can grow to more than a metre long, and weigh 25 kg
  • They tend to be solitary daytime feeders, eating small fish & crustaceans
  • Their large mouths are use to ‘inhale’ or suck in prey
  • The colouring of an individual can vary from red to brown
  • These fish have little black spots around the eyes (I’ve no idea why).
  • Their habitat is in the vicinity of coral reefs, from shallows to 100 m deep
  • Spawning mainly occurs in Dec & Jan during a full moon
  • Large numbers gather in a single location to mate in a mass spawning
  • These groupers are slow breeders, which compounds the overfishing problem
  • They are easy mass targets at spawning time; hence the need for a closed season

Nassau Grouper (Melinda Riger / G B Scuba)

A Nassau Grouper glumly contemplates the possibility of extinctionNassau Grouper (Melinda Riger / G B Scuba)

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Nassau Grouper (Melinda Rogers / Dive Abaco)

Credits: Melinda Riger / Grand Bahamas Scuba (1, 2, 3, 5, 6); Melinda Rogers / Dive Abaco (4, 7)

ENDANGERED SPECIES ON ABACO, BAHAMAS (2): KIRTLAND’S WARBLER


Kirtland's Warbler Abaco Bahamas (Bruce Hallett)

ENDANGERED SPECIES ON ABACO, BAHAMAS (2): KIRTLAND’S WARBLER

The rare Kirtland’s warbler (Setophaga kirtlandii) is rightly prized both in its very specific breeding grounds and in its winter migration locations. Abaco is fortunate to be one of these, but they are extremely difficult to find, even with local knowledge. The latest IUCN Red List assessment of numbers of adult warblers (2018) gives a figure of 4,500 – 5,000. The species is categorised as ‘near-threatened’. Numbers are gradually increasing, thanks to a major recovery plan and intensive conservation measures in areas where they nest. 

WHERE THEY LIVE

SPRING & SUMMER Mostly, the KIWA population lives and breeds in very specific areas of Michigan and Ontario, where jack pines are found. As numbers have increased, the range has expanded more widely into Wisconsin and Ohio.

A Kirtland’s Warbler in the jack pines of Michigan (Vince Cavalieri)Kirtland's Warbler, Michigan (©Vince Cavalieri)

FALL & WINTER the population migrates to the Bahamas & TCI, where they tend to choose remote scrub and coppice areas to live until the spring when they return north in April. This range map shows the extremely specialist habitat choices of these migratory birds.

Kirtland's Warbler Range Map wiki

THE MAIN THREATS TO THE SPECIES

  • Mankind is the primary threat. The breeding areas are particularly vulnerable from deforestation and clearance of the jack pines that are essential for successful nesting and breeding – and therefore the survival – of the species
  • Encroachment by development is a major concern (as with so many species everywhere)
  • KIWAs are vulnerable to nest parasitism by brown-headed cowbirds in the breeding areas
  • Their winter habitat is mostly in remote or protected areas, but on Abaco a proposed development in the National Park where they live will probably wipe them out, if built   
  • Overall, habitat degradation at one end of the migration – in particular the breeding grounds – poses a serious risk to the species; at both ends, extinction could loom again

Kirtland's Warbler, Ohio (Tom Sheley)

WHAT TO LOOK OUT FOR?

  • Gray head with a blueish tinge, gray-brown back
  • Yellow throat & underside, with some dark streaking
  • Females are paler and more streaked
  • Split eye rings – white crescents above and below eyes
  • Frequent tail pumping and bobbing

Kirtland's Warbler, Abaco Bahamas (Tony Hepburn)

WHAT DO THEY SOUND LIKE?

Some say ‘chip-chip-chip-too-too-weet-weet’. Elsewhere I have found it claimed that they produce ‘a loud tchip, with song an emphatic flip lip lip-lip-lip-tip-tip CHIDIP‘ (Arnott). I’m not a big fan of phonetic spelling for bird sounds. Here’s a sample for you to assess:

 Ross Gallardy / Xeno-Canto

Kirtland's Warbler, Abaco Bahamas (Bruce Hallett)

WHO WAS MR KIRTLAND?

Jared Potter Kirtland (1793-1877) portrait

Jared Potter Kirtland (1793-1877)

Jared P. Kirtland (1793 – 1877) was an Ohio scholar, doctor, judge, politician & amateur naturalist. He was a man of many and varied interests and talents, not-untypical of his time. In the field of natural history, Kirtland’s name lives on in his warbler & also in a couple of snake species.

The Bahamas Postal Service is commendably active in producing wildlife stamps

Credits: Bruce Hallett (1, 5, 6); Vince Cavalieri (2); Tom Sheley (3); Tony Hepburn (4); Birds of North America (range map); Ross Gallardy / Xeno-Canto (audio file); Birdorable (cartoon); BPS (KIWA stamp). Special thanks for all use permissions for images of this rare bird.

Kirtland's Warbler, Abaco Bahamas (Bruce Hallett)

ENDANGERED SPECIES ON ABACO, BAHAMAS (1)


Abaco (Cuban) Parrot, Bahamas (Nina Henry)

ENDANGERED SPECIES ON ABACO, BAHAMAS (1)

May 15th is – was – Endangered Species Day worldwide. I missed it, of course I did. Typical. So, belatedly, here’s the first of a short series highlighting the Endangered Species of Abaco, Bahamas. It will include a couple of species formerly found on Abaco but now extirpated and hanging on in tiny numbers in specific habitats in the wider Bahamas archipelago. Regrettably, much of the endangerment has been caused, or substantially contributed to, by a dominant species that tends to prize self-interest over broader considerations.

ABACO PARROT

Abaco (Cuban) Parrot, Bahamas (Nina Henry)

These gorgeous and beloved parrots nest uniquely in limestone ground burrows in the island’s protected National Park in the south of the island, a vast area of pine forest. They are the big success story of Abaco conservation. I was fortunate enough to become tangentially involved with the parrots just as years of patient research and intensive fieldwork were beginning to impact positively on a dwindling and barely sustainable population (fewer than 1000 birds). Adults and particularly the chicks in breeding season were very vulnerable to the attentions of feral cats, non-native racoons and rats. Nests were protected, cameras were deployed, and predators eradicated.  

Abaco (Cuban) Parrot Nest & Chick, Bahamas (Caroline Stahala)

The work of scientists such as Caroline Stahala was (and still is) supported by local organisations such as Bahamas National Trust and Friends of the Environment Abaco. Local communities lent valuable encouragement and enthusiasm to the project. No one can fail to be uplifted by the sight of a flock of these parrots flying overhead, flaunting their bright green, red and blue feathers that flash in the sunlight. Even the sound of a flock squabbling in the trees like noisy children just let out of school is a joy. Here’s a sample, recorded at Bahama Palm Shores: see if you agree…

Keith Salvesen / Rolling Harbour

10 years on, these gorgeous, raucous and intriguing birds have made a comeback, and the pleasure of their continuing visual and audible presence is hopefully secure. 

Credits: Nina Henry (1, 2); Caroline Stahala (3); Keith Salvesen (4) and audio clip

 

CUBAN PEWEE: PICTURE PERFECT ABACO (12)


CUBAN PEWEE: PICTURE PERFECT ABACO (12)

Cuban Pewee, Abaco, Bahamas (Keith Salvesen / Rolling Harbour)

The Cuban pewee Contopus caribaeus bahamensis (sometimes called the crescent-eyed pewee) is the smallest of the four so-called ‘tyrant’ species found on Abaco. These flycatchers are tiny compared with their kingbird cousins. You can clearly see the tiny hooked tip at the end of the upper beak, which helps to trap caught insects.

Like other flycatchers, the Cuban pewee has distinctive whiskers around the base of the beak. These are in fact feathers that have modified into bristles. They act as tactile sensors that help detect and target aerial insects. The pewee will then dart from its perch to intercept some passing tasty winged morsel (known sometimes as ‘hawking’), returning to the branch to swallow the snack.

Of all small unassuming brownish birds – and there are a great many – I consider the pewee to be one of the prettiest. It is also rewarding to photograph, being inquisitive by nature and as likely to pose for the camera as to fly away.

Photo: Keith Salvesen / Rolling Harbour Abaco

 

SEA URCHINS: PICTURE PERFECT ABACO (11)


SEA URCHINS: PICTURE PERFECT ABACO (11)

Sea Urchin, Abaco, Bahamas (Melinda Rogers / Dive Abaco)

As every swimmer knows, or eventually finds out the hard way, it’s not only Blue Suede Shoes that should not be stepped on. But however painful the consequences of a misstep, it’s hard not to find some beauty in an urchin living in a thriving reef environment. The wonderful anatomical diagram by Alex Ries shows everything you could conceivably want to know about one of nature’s most proficient foot-stabbers (if only all such diagrams were presented so simply and clearly).

Sea urchin anatomy (Alex Ries)

The internal organs depicted resemble a bad trip in the bowels of a vacuum cleaner; or (narrow your eyes) an experimental painting from one of the less successful schools of early c20 modern art, soon to be swept aside by Cubism. Note that the mouth is located where you might expect to find the opposite end, and vice versa.

I photographed the urchin test (skeleton) below at Delphi. It was large and almost entirely undamaged (very rare in my experience). The bright faintly greenish white is set off by the palest of pinks. Whatever your view of how creatures came to exist, imagine the creation or evolution of calcium carbonate into a small symmetrical structure as beautiful, detailed and complex as this. If you are short of a lockdown recreation, maybe try to draw it.

Sea Urchin Test / Skeleton, Abaco Bahamas (Keith Salvesen / Rolling Harbour Abaco)

Photo credits: #1 Melinda Rogers / Dive Abaco; #2 Anatomy Diagram, Alex Reis (5 stars for making it available free on Wikimedia); #3 Keith Salvesen / Rolling Harbour Abaco

BAHAMA YELLOWTHROAT: PICTURE PERFECT ABACO (10)


Bahama Yellowthroat, Abaco Bahamas (Gerlinde Taurer)

BAHAMA YELLOWTHROAT

The Bahama Yellowthroat Geothlypis rostrata  is one of 5 bird species endemic to the Bahamas. Three other endemics found on Abaco are the Bahama Woodstar, Bahama Warbler and Bahama Swallow. The fifth is the endangered Bahama Oriole, now only found in very small numbers on Andros. They once lived on Abaco, but are unrecorded there since the 1990s and are considered extirpated. You can find out more about all these endemic birds together in a nest HERE.

Bahama Yellowthroat, Abaco Bahamas (Gerlinde Taurer)

I’m fond of these birds with their striking Zorro masks. It is one of the few species that I am able to imitate with sufficient accuracy to draw one out of the coppice. Their call is usually described as a ‘wichety-wichety‘. I realise that the talent to mimic it has no other use in life. Here’s a short recording I made – the Yellowthroat is the first and last call of the sample, with other species in between.

Photo Credits: Gerlinde Taurer (1, 2); Bruce Hallett (3,); sound recording Keith Salvesen / Rolling Harbour

Bahama Yellowthroat, Abaco, Bahamas (Bruce Hallett)

 

CORAL SUNSHINE: PICTURE PERFECT ABACO (9)


CORAL SUNSHINE: PICTURE PERFECT ABACO (9)

coral-in-sunlight-melinda-rogers-dive-abaco

Off the east coast of Abaco lies one of the longest barrier reefs in the world. Some authorities suggest it is the third longest, but the exact ranking of the top dozen coral barriers is a matter for considerable debate. None of the lists I have just checked agree, except that the Great Barrier Reef is the outright winner. I suspect that the problem lies in the loosely generalised description of ‘barrier reef’ and in variations of the appropriate criteria for determining length (it may also depend on who is doing the measuring, of course).

Melinda Rogers of Dive Abaco took this bright sunlit ‘Coralscape’ in the Fowl Cays National Park. It’s a place I have tentatively snorkelled around with great pleasure, despite being in the top dozen most useless swimmers in the world (my appalling underwater videos were disqualified from the rankings for being… rank).