SEABIRDS, SHOREBIRDS & WADERS: 30 WAYS TO DISTINGUISH THEM


Magnificent Frigate male Wikipics
Magnificent Frigatebird

SEABIRDS, SHOREBIRDS & WADERS: 30 WAYS TO DISTINGUISH THEM 

I have recently been looking at hundreds of photos of birds, many with aquatic or semi-aquatic lives. These can be broadly categorised as seabirds, shorebirds or wading birds. But with some bird breeds, there can be doubt as to which category applies. There is the strict Linnaean ordering of course, but in practice there is a degree of informal category overlap and some variation in the various bird guides. This is especially so between shorebirds and the smaller, less exotic wading birds. Shorebirds may wade, and wading birds may be found on shores. Then I remembered a past blog post by the estimable BEACH CHAIR SCIENTIST that I thought deserved an outing here. I re-blogged the chart from BCS early last year. In the meantime site followers and site hits have surprisingly increased considerably, but I suspect only the dedicated make time to sift through any blog’s archives…  Even if you have no problem distinguishing birds in the 3 categories, there are avian characteristics within each list that are interesting observations in themselves. 

10 CHARACTERISTICS OF SEABIRDS 

Whitetailed Tropicbird WikiPicWhite-tailed Tropicbird

(Examples include albatross, auk, booby, frigatebird, fulmar, gannet, penguin, petrel, puffin, shearwater, and tropicbirds)

1. Seabirds are pelagic, spending most of their lives far out at sea.
2. Seabirds move toward to coastal areas to breed or raise young for a minimal amount of time.
3. Seabirds are light on their undersides and dark on top (an adaptation known as countershading).
4. Seabirds have more feathers than other types of birds for more insulation and waterproofing.
5. Seabirds have flexible webbed feet to help gain traction as they take off for flight from the sea.
6. Some seabirds have unusually sharp claws used to help grasp fish under the water.
7. Some larger seabirds (e.g. albatross) have long, slim wings allowing them to soar for long distances without getting tired.
8. Some smaller seabirds have short wings for maneuvering at the surface of the water.
9. Seabirds have specialized glands to be able to drink the saltwater and excrete salts.
10. Some seabirds (e.g. gannets) have a head shape that is usually tapered for more efficiency in plunge diving.

10 CHARACTERISTICS OF SHOREBIRDS 

Wilson' Plover male Wikipic

Wilson’s Plover

(Examples include avocets, black skimmer, oystercatchers, plover, sandpiper, and stilt)

1. Shorebirds have long legs, pointed beaks, and long pointed wings.
2. Most shorebirds are migratory (Impressively some shorebirds fly non-stop for 3-4 days, equivalent to a human running continuous 4-minute miles for 60 hours).
3. Shorebirds wade close to the shore and poke their bills into the ground in search of food.
4. Shorebirds are small to medium size wading birds.
5. Shorebirds tend to frequent wetlands and marshes and are biological indicators of these environmentally sensitive lands.
6. Shore birds are of the order Charadriiformes.
7. Shorebirds are very well camouflaged for their environment and their appearance may vary from place to place as plumage (feather colors) are gained or lost during breeding.
8. Shorebirds typically range in size from 0.06 to 4.4 pounds.
9. Oystercatchers have a unique triangular bill that is a cross between a knife and a chisel.
10. The black skimmer is the only native bird in North America with its lower mandible larger than the upper mandible, which helps the bird gather fish as it skims the ocean surface.

10 CHARACTERISTICS OF WADING BIRDS 

Great Egret Wikipic
Great Egret

(Examples include crane, egret, flamingo, herons, ibis, rail, spoonbill, and stork)

1. Wading birds are found in freshwater or saltwater on every continent except Antarctica.
2. Wading birds have long, skinny legs and toes which help them keep their balance in wet areas where water currents may be present or muddy ground is unstable. Also, longer legs make it easier for them to search for food (forage) in deeper waters.
3. Wading birds have long bills with pointed or rounded tips (depending on what is more efficient for the types of food the bird consumes).
4. Wading birds have long, flexible necks that can change shape drastically in seconds, an adaptation for proficient hunting.
5. Herons have sophisticated and beautiful plumes during the breeding season, while smaller waders such as rails are much more camouflaged.
6. Wading birds may stand motionless for long periods of time waiting for prey to come within reach.
7. When moving, their steps may be slow and deliberate to not scare prey, and freeze postures are common when these birds feel threatened.
8. Adult wading birds are quiet as an essential tool for hunting. Wading birds may be vocal while nestling or while in flocks together.
9. Many wading birds form communal roosts and breeding rookeries, even mixing flocks of different species of wading birds or waterfowl.
10. Wading birds fully extend their legs to the rear when flying. The neck may be extended or not while in flight, depending on the species.

These lists were put together in useful chart form. Please check with BCS (link above) if you want to ‘borrow’ itseabird shorebird wading bird chart ©beachchairscientistImage Credits: Table – ©Beach Chair Scientist; Pics – good old wiki

ABACO FROM SPACE: NASA / ISS VIEWS 225 MILES ABOVE THE BLUE PLANET


STS060-84-32

ABACO FROM SPACE:  NASA  /  ISS VIEWS 225 MILES ABOVE THE BLUE PLANET

I have had another look through NASA‘s stock of Bahamas images taken from the INTERNATIONAL SPACE STATION. They come in differing formats. Over time the Station’s orbit takes it directly over or close to Abaco. In the past I have posted images of Hurricane Irene and Hurricane Sandy taken from space; and one of the astonishing Bahama variations of the colour BLUE. Here is a further selection.

The first two images show an orbit from north to south. I have annotated the first for those unfamiliar with the geography of Abaco. I assume the next was taken only a second or two later, with the whole of the southern tip / National Park / Hole-in-the-Wall area of Abaco now shown.

Abaco Map NASA:ISSA annotated STS060-84-33

This image gives an idea of the underwater connection between the island land masses. Here, a corrugated underwater sequence of ridges and troughs can be seen linking the southern end of Abaco with the south western end of Grand Bahama. Moore’s Island and, barely visible below it, Gorda (‘Castaway’) Cay rise above sea level between the two larger islands. The Berry Is. and Great Harbour Cay can be seen bottom left; Eleuthera snakes downwards bottom right. [At Rick Guest's suggestion, I have rotated the image 90˚ from the original to make sense of a view distorted by angle (the space station's), earth curvature and my own misinterpretation... It makes far more sense now, and I have corrected geographic errors accordingly... I've also added an annotated aeroplane's-eye view below it, taken from much closer to the earth and therefore less subject to distortion. Many thanks, Rick]STS108-724-71 copyAbaco Map  - Island relationships

Abaco seen from the southeast. Little Abaco and Grand Bahama are at the top, and all are shown inter-connected underwater. The reef chain of the Abaco Cays – the world’s third longest barrier reef – can clearly be seen on the rightISS017-E-12812

This image appears to be a blow-up of the sharper ‘filmic’ second one above. The detail has become hazy and indistinct, though part of the island-long ribbon of highway remains clearly visible. Time for a photo-enhancing experiment…
NASA clip

I played around with the contrast and colour settings of the photo above, to see what effect it produced (below). The most marked result is that areas of low water  – the coastline, the underwater high ground, the Marls and mangrove swamps, the low water of Cherokee Sound – became vividly highlighted. I don’t know what the small russet patches are, particularly visible in the Marls. My (ill-)educated guess is that they represent mangrove / mud islands that are underwater at high tide only, and that were in tidal transition as the Space Station passed overhead. Any ideas welcomed via the comment box.NASA clip - Version 2

QUEEN ANGELFISH (Holacanthus ciliaris) – BAHAMAS REEF FISH (2)


Queen Angelfish Holacanthus ciliaris

QUEEN ANGELFISH (Holacanthus ciliaris)  – BAHAMAS REEF FISH (2)

The Queen Angel is one of several reef fish species where the difference in colouring between juveniles and adults is marked.  They are commonly found in the waters of Florida and the Bahamas, with a range extending to the Gulf of Mexico. Adults can grow to 3.5 lbs (to mix metric with avoirdupois) and they can live up to 15 years. Like all Angelfish, they rely on their pectoral fins for propulsion as they forage on the reefs for their mixed diet of sponges, coral, plankton, algae, and even jellyfish. As the photo below shows, they have no problem swimming upside down…

QUEEN ANGELFISH (JUVENILE) Juvenile Queen Angel ©Melinda Riger GB Scuba

Evidence suggests that adult Queen Angels may form ‘monogamous’ pairings. Brief research in the factosphere suggests that the proposition is somewhat tenuous. Maybe pairs just like hanging out – possibly to gain some territorial advantage – and anthropomorphising that into lifelong partnership terms may be overstating the relationship… Whether wed for life or not, the actual mating process is remarkably efficient. The pair snuggle up close, simultaneously releasing large quantities of sperm and tens of thousands of eggs. The fertilised eggs hatch within a day. Respect!

QUEEN ANGELFISH (ADULT)Queen Angel fish ©Melinda Riger GB ScubaQueen Angelfish ©Melinda Riger / Grand Bahama ScubaQueen Angelfish (juv) ©Melinda Riger @GBS

Photo Credits for the amazing main images: ©Melinda Riger (Grand Bahama Scuba), with thanks; header image WikiPic

RICKY JOHNSON, ABACO NATURE GUIDE & ENTHUSIAST 1964-2013


Ricky Johnson, Abaco, Bahamas

FOR RICKY JOHNSON, ABACO NATURE GUIDE & ENTHUSIAST 1964-2013 

Ricky Johnson Bahama Palm Shores 1

No one who knew Ricky, or even merely met him, could doubt his charisma, his infectious enthusiasm for life, and for Abaco and its natural history. His Abaco Nature Tours were legendary. As non-islanders, we knew that a day out in Ricky’s company would be a hectic and memorable one. He knew where all the birds were to be found – and enticed the shy ones out of the coppice with his trademark calls. He was all-seeing and all-knowing – information about Abaco’s natural history, social history, geology, poisonous plants and bush medicine would stream from him irrepressibly throughout the day. Ask him a question? He’d know the answer. He seemed never so happy as when he spotted something and pulled the truck over, leaping out with the door open so all could hear his running commentary as he explained the properties of some small plant that most would have failed to notice. Accompanied, of course, by a gag and THAT laugh.


Ricky Johnson Bahama Palm Shores 3

In many ways, it is impertinent for occasional blow-ins to become involved in what is the island’s grief over Ricky’s tragically young passing. However in the short time we knew him – far too short – we both came to feel we had known him for many years. That was the Ricky effect. He was a joy to know, and we will remember him with joy as well as with sadness.

Ricky Johnson Pishing Woodstars Crossing Rocks Abaco

Land Crab : Ricky Johnson 2

ABACO HISTORY: SHIPS, MAPS & HOLE-IN-THE-WALL


Schooner (Wiki)

I have posted several times about Hole-in-the-Wall, the geological feature and historic nautical landmark at the southern tip of Abaco. I’ve covered the frankly concerning 15-mile trip to reach it and the eponymous lighthouse;  its history in both maps and pictures; and its destruction by Hurricane Sandy last October. A full index of the related Hole-in-the Wall posts can be found at the foot of this page (most recent first). I am returning to one specific early picture of HitW because of interesting information supplied by Capt Rick Guest.

THE PICTURE The lovely aquatint below is by J. Wells, based on a sketch by a naval officer (“Half-Pay”), published in the 1803 NAVAL CHRONICLE by founder J.Gold of Shoe Lane, London. It’s quite small picture, measuring 5½” x 9″. As I said in the original post, “you may be looking at a screen clip of a scan of the book plate of the earliest surviving depiction of Hole-in-the Wall. If anyone knows of an older one, please get in touch. And can anyone identify what kind of sailing vessels these are (I wouldn’t know a brigantine from a clipper…)?”.

THE SHIPS I am now better informed about historic ships (though no wiser). I am very grateful to Rick Guest for his various contributions, including his ID of the ships in the aquatint: “The vessel on the left (west) is a Topsail (‘tops’l’) SCHOONER. Because of the angle on the other vessel, my guess is it’s a BRIG. Brigs have 2 masts, usually with a large ‘Spanker’ (aft sail).” The schooner is flying the Union Jack. The two rowing boats setting off from the ships seem from the detail to be heading towards land – perhaps to find fruit or other provisions.

hole-in-the-wall-print-1803

THE GEOLOGY Besides showing Hole-in-the-Wall between the 2 ships (as it was until Hurricane Sandy struck in October 2012), there is an additional feature that I did not originally remark on. To the right of the aquatint is a single rocky islet. Its left side and the corresponding end of the mainland clearly evidence the previous existence of another longer-arched hole, its roof presumably long gone by 1803. Earlier maps make no reference to a second Hole, though it’s possible the oldest refer to the larger, more significant hole until it collapsed and left the smaller hole to bear the name. At all events, the islet to the right in the aquatint is now largely submerged, though it can be seen from an aerial view. If anyone has a photo of it taken from the sea, with the promontory and lighthouse behind, please get in touch.

Hole-in-the-Wall aerial view

MAPS

I have found some more images of historic maps of Abaco to add to the earlier collection.

1. Johannes van Keulen 1728  c17/ early c18 Dutch cartographer. The top image of two is from a less well-reproduced edition, possibly an early one. The HitW area is uncompromisingly called ‘Hole Rok’. This is a rare instance of another ‘Hole Rok’ being marked of the south-west tip of Abaco. The main island itself is often described at this time as I. Lucaj(y)onesque, or similar derivative from the word ‘LUCAYA’ (Lucyan people being the early inhabitants of the Bahamas region). Notable here is the use of the word ‘I. Abbaco’ for a cay on the east side rather than the whole island.

van Keulen mod

This second much clearer (and later?) print of the same van Keulen map demonstrates why Hole-in-the-Wall is of such historic importance to the Abacos. It clearly marks the only settlement of any significance known to seafarers and cartographers of the time. Other contemporary maps are the same. It is the only named place on Abaco. Buildings are even shown here, though nowhere else on the island. It may well be fair to conclude that until at least 1800, HitW was the ‘capital’ of Abaco. Nowadays it is simply a functioning lighthouse in urgent need of attention and repair, with the abandoned buildings of the lighthouse station clustered round it (the light was automated in 1995). There is no settlement and there are no dwellings, not even visible ruins.van Keulen 1728

2. Thomas Kitchin 1782 Kitchin was a well-known English c18 cartographer who famously mapped the counties of Britain. He also worked in the Caribbean for a time. The clip below is taken from his map “West Indies according to Best Authorities“. The image doesn’t do the map justice. I own it (thanks, Mrs RH) and had just framed it when someone asked for a quick photo, so it is taken through glass (too lazy to remove it – will try to improve the image later). Great Abaco is now specifically named in its own right as an island, though the Abacos group as a whole retains its historic Lucayan name. Again, ‘The Hole in the Rock’ is the only place-name included. As a side-note, Grand Bahama has progressed from ‘Bahama Eyland’ to ‘Great Bahama’Abaco map

3. B.T.Welch, published F.Lucas Jr 1823 The top map shows the entire West Indies. I have located a clearer version of it and added the clip below it showing the detail of the top left corner Northern Bahamas corner

Abaco Map B.T.Welch published F.Lucas Jr 1823One hundred years on from the van Keulen map, and a few familiar names are starting to appear, especially with the ‘Kays’. ‘Hole of the Rock’, as it was now called, is still almost the only named place on the main island. I can’t make out what the bearing and date under the name means – any suggestions welcome. In passing, I note that ‘Gordo K(ay)’ is named, the earliest mention I have found. It is now of course ‘Disney Island’, and good luck to it… ‘Great Bahama’ has now become. finally, Grand Bahama.Abaco B.T.Welch published F.Lucas Jr 1823

4. George Cram 1898 This map demonstrates how, even in relatively modern times, mapmakers can take their eye off the globe, as it were, and go wrong. True, ‘Hole in the Rock’ is named and its lighthouse (completed 1836) is marked. However, some of the attributed place-names seem surprising – for example, Moore’s Island has strangely been called Moose Isl. And for a map not much more than 100 years old, in the ‘Superior Atlas of the World‘, the general topography of Abaco is way off the mark. Either that or the Crossing Rocks area in the lower quarter of the island below “Cheering Sound” – a slim land-narrow just few metres wide from east to west coast – has been on a crash diet in the intervening century… It’s basically the width of the road with a beach on either side.

Abaco 1898 George Cram

LIST OF PREVIOUS HitW POSTS

HOLE-IN-THE-WALL, ABACO: THE ‘HOLE’ THAT’S NO LONGER A WHOLE December 9, 2012

HOLE-IN-THE WALL ABACO: “MIND THE GAP” – A NEW ISLET IS BORN November 8, 2012

ABACO’S ‘HOLE-IN-THE-WALL’ BEFORE SANDY DEMOLITION: FIRST & LAST EVER IMAGES November 5, 2012

HOLE-IN-THE-WALL TO GAP-IN-THE-WALL: HURRICANE SANDY SMASHES ABACO LANDMARK November 3, 2012

 HOLE-IN-THE-WALL ABACO: HISTORIC 1803 DESCRIPTION & AQUATINT May 23, 2012

 ABACO & HOLE-IN-THE-WALL, BAHAMAS: A SHORT HISTORY IN MAPS April 8, 2012

 “TO THE LIGHTHOUSE…” A TRIP TO HOLE-IN-THE-WALL, ABACO May 25, 2011

 

SPOTTED DRUM FISH – BAHAMAS REEF FISH (1)


SPOTTED DRUM FISH Equetus punctatus BAHAMAS REEF FISH (1)

This post is the first of a planned series on Bahamian reef fish. Those who follow this blog (I thank you both) may recall with horror (or worse, pity) my own efforts with reef fish, using a tiny cellphone-sized video camera.  Misty stills culled from video footage. Enthusiastically wobbly movies as I struggle to swim and breathe simultaneously in an alien element. I am more underwater CLOUSEAU than COUSTEAU. However, thanks to Melinda Riger, who with husband Fred runs GRAND BAHAMA SCUBA, I have kind permission to borrow and display images from her stock of wonderful reef fish photographs.

The spotted drum fish (or Jack-knife fish) belongs to a large worldwide family, the Sciaenidae. Besides other drum varieties, the family includes ‘croakers’. These species are all named for the repetitive throbbing or drumming sounds they make. This involves the fish beating its abdominal muscles against its swim bladder. If I find out the reason for this (Species communication? Food call? Alarm? Warning? A piscine ‘advance’? Happiness?) I will add it here in due course. Here an example of an atlantic croaker from the excellent DOSITS site (Discovery of Sounds in the Sea)

The spotted drum is one of the few fish of the species to inhabit coral reefs – most are bottom-dwellers (often in estuaries), avoiding clear water. These fish tend to be nocturnal feeders, feeding on small crabs, shrimp and small invertebrates. As far as I can make out they are solely (or primarily) carnivore, and do not graze on algae of other reef plant life.

Drumfish

Drumfish

The photos above are of adult spotted drums. The ones below are of juveniles, and show the remarkable growth-pattern of these fish, from the fragile slender creature in the top image, through the intermediate phase of the one below it (with the amazing brain coral), to the striking adult versions above. People like to keep these pretty fish in aquariums; fine, I’m sure there are plenty to go round, but these ones look pretty happy to me in their natural reef environment…

Juvenile Drum Fish (pre-school)Juvenile Drumfish 2 ©Melinda Riger GB Scuba

Juvenile drum fish (school-age)

Juvenile Drumfish ©Melinda Riger GB Scuba(Header image credit: Wiki-Cheers)

Finally, I’ve just come across this short video from a “Florida Aquarium”, showing how these fish swim. It rather looks as though it has been fin-clipped for some reason… or just damaged, maybe

BMMRO: WHALE ETC SIGHTINGS; BLAINVILLE’S BEAKED WHALES; WINTER NEWSLETTER


D

Blainville’s Beaked Whale, Abaco, Bahamas

SIGHTINGS REPORT OCT – DEC 2012

The last quarter of 2012 produced relatively few open-ocean CETACEAN sightings, not least because of a reduction in spotting trips during the period, with some members of the team elsewhere in the world completing their research. SIRENIAN activity is thankfully on the increase, with reporting opportunities increased by the manatees’ preference for sticking close inshore, usually in harbour areas. Georgie has gained her first yellow spot as Abaco’s only resident manatee following her long trip over from the Berry Is. (and away from mother Rita) last summer. She has  taken up residence in Cherokee. She performed a worrying vanishing trick during Hurricane Sandy, holing up (presumably) in seagrass off-shore, and (definitely) in an inshore channel for some of the time. She went AWOL again before Christmas, but has returned to Cherokee in good condition after a short vacation. Having shed her tag (several times) it was not possible to track her. The big plus is that she has proved capable of independent living, and has not become reliant on proximity to humans and their offerings of cabbage leaves etc… This photo was taken at Cherokee a few days ago.

Manatee Georgie, Abaco, Bahamas

The other notable new entry is a manatee sighting in the Freeport area of Grand Bahama. A single photo exists – a head shot – but it hasn’t been possible to identify the creature as a known one. (S)he may be a new visitor to the Bahamas. People in the area are asked to report any further sightings in the area to the BMMRO – and if possible to get a picture!
BMMRO CETACEAN SIGHTINGS OCT:DEC 12

BLAINVILLE’S BEAKED WHALES

RANGE MAP                                                         IUCN RATING “DATA DEFICIENT”

        

Mid-frequency broadband sounds of Blainville’s beaked whales

Recent research has been carried out on the sound variations of this relatively little-understood species of whale. “Recordings from acoustic tags show that five Blainville’s beaked whales produced mid-frequency broadband sounds on all of their deep dives, with each sex producing two different sound types. These broadband sounds are atypical of the regular echolocation sounds previously described for this species. One male produced a total of 75 sounds over four dives, between the depths of 109 and 524 meters, and four females produced a total of 71 sounds over 18 dives, between the depths of 305 and 1289 meters. Ninety-six percent of the male sounds and 42 percent of the female sounds were produced before the onset of foraging echolocation sounds, and all were produced before the deepest point of the dives. These sounds may be candidate communication signals, with their production timed to mitigate the risk of both predation and hypoxia (oxygen deprivation).”

The report includes sample sounds from the 3 BBWs shown below, and the one heading the page. I haven’t found a way to embed the sounds, but I am working on it (there’s a time -consuming method involving conversion to MP3, but maybe another day…)

Blainville’s Beaked Whales, Abaco, Bahamas Blainville's Beaked Whale AbacoDA

Thanks to the prolific DEAR KITTY for a cross-reference to this topic on her website, featuring a fine video of  BBW in French Polynesia

Finally, the action-packed, information-filled, image-laden 4 page winter newsletter. Click below to open.

BMMRO WINTER NEWSLETTER 2012 (Jan13)

Georgie Manatee BMMRO SUPPORT LOGO

mantsw~1