‘SOCIABLE DOLPHINS’: MELON-HEADED WHALES

May 22, 2018 by Rolling Harbour

‘SOCIABLE DOLPHINS’: MELON-HEADED WHALES

Last month, BMMRO undertook a joint expedition with FIELD SCHOOL to carry out research on sperm whales. This took them out into deep water, where another, quite different, cetacean species was also encountered on the final day – a huge pod of more than 100 melon-headed whales Peponocephala electra.

The melon-headed whale is in fact – like the FALSE KILLER WHALE I recently wrote about – a species of dolphin. It is sometimes more accurately called the melon-headed dolphin, which removes any confusion. These creatures are oceanic, preferring deeper waters. For that reason they are not often encountered, despite being quite common in tropical and sub-tropical waters around the world.

The MHW belongs to a dolphin species commonly known as blackfish. Other dolphins in this group included, for the Bahamas, the pygmy killer whale and the more frequently encountered pilot whale, a species than can be seen in the Sea of Abaco.

In some of these photos you can see the distinctive white lips of the MHW

Melon-headed whales are notably social animals. They live in large groups – often more than 100-strong (as the expedition found), up to as many as 1000 individuals. Within these large groups, smaller groups of a dozen or so form and stay close as they swim.

Note the ‘Rainbow Blow’ caught in this photo Melon-headed whales, Bahamas (BMMRO / Field School)

MHWs appear to communicate or perhaps to bond by touching flippers. MHWs also associate with other dolphin species, and they have even been recorded with large whales such as humpbacks.

Other observed behaviour includes sub-surface resting in numbers, boat-wave riding, and so-called ‘spy hopping’ (above). This last activity may be carried out by several resting animals, which jump vertically out of the water and splash back again into the ocean (see also the Header image).

This video was recorded during the expedition. You’ll get a very good idea of the size of the group from the drone shots as they pull out. I doubt that many people would expect to see such large sea creatures in such numbers – it must be an awesome** sight.

10 MELON-HEADED FACTS WITH WHICH TO ASTOUND YOUR LOVED ONES

The MHW’s head is rounded, lacking the obvious beak of more familiar dolphins
The darker grey face is sometimes called a ‘mask’
Their distinctive white lips are a good identifying feature
They are capable of swimming at very fast speeds
Like other dolphins, they make series of low jumps out of the water as they swim
Their groups often contain 100 individuals, up to as many as 1000
An adult grows to around 3m / 10′ long
They live for at least 20 years, and females may live as long as 30 years
As with many certaceans, their favourite food is squid
Oh, did I mention that they are really dolphins and not whales at all?

CREDITS: all fantastic photos & the original of the video clip – © BMMRO / Field School

** In its true and original meaning of ‘inspiring wonder and awe’ (historically, in a religious sense), rather than the diluted modern usage as in ‘awesome pizza’ or ‘awesome selfie’

LOGGERHEAD KINGBIRD: BENIGN ‘TYRANT’ OF ABACO

May 17, 2018 by Rolling Harbour

LOGGERHEAD KINGBIRD: BENIGN ‘TYRANT’ OF ABACO

Abaco is home to 4 main so-called tyrant flycatchers (Tyrannidae): the loggerhead kingbird, the gray kingbird, the La Sagra’s flycatcher and the Cuban pewee. All are common permanent residents except 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.

The loggerhead featured here in several poses is a watchful sentinel at Delphi. His preferred perches are in the edge of the coppice round the pool or at the edge of the main drive. From time to time he will leave his perch to catch a passing insect by ‘hawking’, returning to the same place to eat it.

Loggerhead and gray kingbirds can be quite easy to confuse. A couple of years ago I wrote about how to distinguish them, and with gray kingbirds in residence now this is probably a good time to set out the distinctions again.

LOGGERHEAD Tyrannus caudifasciatus vs GRAY Tyrannus dominicensis

DIFFERENCES and SIMILARITIES

TOP TIP ANY KINGBIRD SEEN IN WINTER WILL BE A LOGGERHEAD

Kingbirds seen between (say) October & March are Loggerheads. Grays are strictly summer visitors
Both are medium size birds and roughly the same size as adults (around 23 cms)
Loggerheads have dark brown to near-black heads, grays have lighter, slate-coloured heads
Loggerheads have a ‘squared’ tip to the tail; grays have a notched tip
Loggerheads may have a whitish fringe at the tip of the tail; grays not so
Loggerheads have yellowish tinges to their white undersides & forewings; grays less so or not at all
Grays have a dark or black ‘mask’ through the eyes, often clear but not always easy to see
Loggerheads allegedly have inconspicuous orange head crests; grays are red. I’ve never seen either!
[*RH personal opinion alert*] Grays have larger, heavier beaks than loggerheads
Grays are territorially aggressive; when they turn up, the loggerheads tend to retreat to the forest

Here is how David Sibley shows the differences

Illustrations: David Allen Sibley

GRAY KINGBIRD FOR COMPARISON

MEMORABLE FACT TO DEPLOY IN CONVERSATION

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

Photo Credits: All loggerheads, Keith Salvesen at Delphi; gray kingbird by Dick Daniels; Illustrations David Sibley

SEA BISCUITS: THEY REALLY DO CONTAIN DOVES – AND MORE!

May 14, 2018 by Rolling Harbour

SEA BISCUITS: THEY REALLY DO CONTAIN DOVES – AND MORE!

Recently I posed the question whether sea biscuits, like sand dollars contain ‘doves’. I had one in my hand, it rattled, I took a photograph through its ‘mouth hole’ and the question was answered. Biscuits do indeed contain doves – see HERE for details and comparisons with dollar doves.

However, I spinelessly* failed to break open the biscuit to check out the contents more closely. I theorised that, because of the 5-way symmetry of these creatures, there would be 5 doves (which are in fact segmented mouth parts) in a biscuit exactly as with a dollar, and amiably challenged anyone to disprove it. [* biscuits and dollars are types of sea urchin – see what I did there?]

Dollar dove in close-up – one of 5 segmented mouth parts inside the ‘test’ (skeleton) Sand Dollar 'Doves', Abaco (Keith Salvesen)

Melissa Ann Guinness from Hope Town has a far more robust attitude to these things and, taking up the challenge, she heartlessly smashed open a sea biscuit from her collection to investigate further. I said I’d publish a correction if my theory was wrong. This is it – though in one arguable sense the theory holds good. It just didn’t go far enough…

In the above picture you can see (a) 4 quarters of a sea biscuit skeleton (b) 10 demi-doves (rather than 5 whole doves) and (c) a small mummified 5-limbed brittle star that was presumably in the creature’s digestive system when it died.

10 ‘demi-doves’ (or, when assembled, 5 doves that (unlike sand dollars) are in 2 parts
Sea Biscuit 'Doves', Abaco (Melissa Ann Guinness)

Complete doves

The final reconstruction – 5 doves and a bonus brittle star

Photo Credits: Keith Salvesen (1, 2, 3, 10); Melissa Ann Guinness (4, 5, 6, ,7 ,8 ,9)

ON LOCATION – DELPHI WEST & EAST

May 10, 2018 by Rolling Harbour

ON LOCATION – DELPHI WEST & EAST

Behold the beach at ‘Delphi West’, Abaco, a fishing lodge of elegance and repute. It overlooks a bay, known by strange coincidence as Rolling Harbour – a mile-long secluded white-sand beach.

4000 mile away is ‘Delphi East’, the counterpart salmon fishery in the mountains of the west of Ireland, of equal elegance and repute.

Between these two equally beautiful yet very different fishing locations is the Atlantic. The wi-fi can be just as iffy in both. I’m posting this from DE on my phone using a phone link. Enjoy a sunrise from DW (note the moon going to bed) to end with. My thumb aches.

FLORAL CORAL: REEF GARDENS IN THE BAHAMAS

May 8, 2018 by Rolling Harbour

FLORAL CORAL: REEF GARDENS IN THE BAHAMAS

Like many of the blues musicians who covered Robert Johnson’s originals, we got ramblin’ on our minds. Specifically to ‘Delphi East’ in Ireland, thus stupidly exchanging 82F sunshine in southern UK for 46F rain in the Emerald Isle. Good for the fishing, if nothing else… So (always remembering that corals are actually creatures and not plants) here’s a bouquet of coral to be going on with until we next meet with wifi!

OPTIONAL MUSICAL RAMBLING

Robert Johnson’s output – a meagre 29 songs in all – formed the bedrock for later bluesmen and the blues / rock crossovers that followed. They mined Johnson’s talent and formed their own new material from it. Here’s the original – you’ve probably heard it or variations of it with different names, a thousand times – some good, some bad, most so-so.

Entire coral pot pourri by Melinda Riger / Grand Bahama Scuba

‘CURIOUS GEORGE’ THE INQUISITIVE BLACK GROUPER

May 4, 2018 by Rolling Harbour

‘CURIOUS GEORGE’ THE INQUISITIVE BLACK GROUPER

Fish, like humans, have a wide variety of temperaments, or so it seems. Resorting to anthropomorphic analysis of animal behaviour is a favourite pastime for humans. Who really knows if a creature is actually feeling shy or confident or playful or aggressive or indeed inquisitive. Often it just seems that way and we are happy to categorise dolphins as playful, sharks as vicious, angelfish as serene, small darting fish as timid and so on.

Occasionally a creature displays a ‘human’ characteristic that seems undeniable. One such is Curious George. He has become used to the divers around the reef where he lives, and greets them. He enjoys the photography sessions and the equipment, even though they may be for recording other fish. He demonstrates inquisitiveness for the strange-looking black-suited creatures that visit his patch. Like many groupers, he likes to be gently patted and stroked.

All this curiosity and friendliness evidences a benign interspecies relationship of symbiotic mutualism, through which both species (man and fish) benefit from the interaction. The mutually beneficial feeling might in broad terms be described as ‘pleasure’.

Or maybe I am just indulging in a bit of over-anthropomorphisation (if there is such a word)…

All photos by one half of the symbiotic mutualism here, Melinda Riger (Grand Bahama Scuba)

THICK-BILLED VIREOS ON ABACO: “NIDIFICATION”

May 3, 2018 by Rolling Harbour

THICK-BILLED VIREOS ON ABACO: “NIDIFICATION”

“Nidification” was one of the new words I learned from the wonderful book Birds of the West Indies by James Bond (a different one – for the full story behind the name click HERE). It means, essentially, the nesting process of a bird. It sounds pleasingly technical for a straightforward concept: nest-building.

Soft furnishings being added

I spotted this TBV making its nest on the edge of the drive at Delphi. I usually think of these cheerful chirpy birds as ‘lurkers’, hanging back in the coppice and not making themselves easily visible. But this nest was right out in the open – possibly not the wisest place for nidification.

If you look up TBV’s in bird books, you may find a reference to nest building in the fork of shrubs or bushes – exactly what was going on here. It quite a messy nest, but then again it looks comfortable and firmly wedged in.

Although I only saw one of the pair actively engaged in the building, another TBV was ‘vocalising’ (there’s another technical term, = singing) nearby, presumably the mate. In a way that humans have been slow to adopt, both birds will be actively involved in raising their family, from incubating the eggs to chick care – feeding, cleaning out the nest and so on.

WHAT DO THEY SOUND LIKE WHEN THEY VOCALISE?