SHEARWATER DIE-OFF ON ABACO: UPDATE


Great Shearwater (part of a die-back event on Abaco) - Dick Daniels

SHEARWATER DIE-OFF ON ABACO: UPDATE

A week ago I posted about the reports of dead and dying Audubon’s shearwaters being washed up on various beaches on the Abaco mainland in and around Cherokee Sound and down to Bahama Palm Shores. I included some advice about how to deal with these poor birds. You can find the post HERE.

Piping plover monitor Rhonda Pearce found a couple of struggling shearwaters in the seaAudubon's Shearwater - part of a die-back event on Abaco (Rhonda Pearce)

The very next day, reports began to emerge of another species, great shearwaters, being found dead or in a distressed state just off-shore or washed up on beaches. Reports were fewer, but covered a wider area, including a bird in a very poor condition at Delphi. Great shearwaters were the ones involved in the die-back event 2 years ago. 

Audubon's Shearwater - part of a die-back event on Abaco (Rhonda Pearce)

Keith Kemp, who made one of the earlier Audubon shearwater reports, found a young great shearwater in trouble in the sea while he was out in a kayak off Cherokee Point. He rescued it and took all sensible precautions to nourish it and make it comfortable but sadly it did not last the night. He has frozen the bird as a specimen in case analysis will help to explain this die-off event.

Great Shearwater - part of a die-back event on Abaco (Keith Kemp)

As I wrote before, these birds of the open ocean may become weakened and exhausted if fishing conditions become adverse. They will drift weakly with the tide, dying at sea or washing up in a very poor state in the tideline or on beaches.  Their prospects of survival if rescued is sadly very slim – I have not yet heard of a success, though I would love to…

Great Shearwater (part of a die-back event on Abaco) - Dick Daniels

Thankfully, during the past week, reports have gradually diminished. I’ve not seen one for a couple of days. With any luck, the current die-off is now over and will not be repeated for several years. However, another one will certainly happen, I’m afraid – maybe in 5 to 10 years time, the usual gap. Twice in two years has made for very bleak, distressing news.

A more cheerful post will be next, I promise. Meanwhile, any further reports or comments would be welcome.

Photo credits: Dick Daniels (1, 5), Rhonda Pearce (2, 3); Keith Kemp (4)

SHARING SHEARWATER SEASHORE SHOCK ON ABACO…


Great_Shearwater_RWDz9 Dick DanielsSHARING SHEARWATER SEASHORE SHOCK ON ABACO…

I return reluctantly to the “Great Shearwater” phenomenon to give, I hope, closure to the topic for this season and with luck for several years to come. A great many people have engaged with the debate about the large number unfortunate birds found either dead or dying in the water or (especially) on the beaches of Abaco and beyond. You can see the original post, a tabulation and map based on the reports I received or came across, and the views of the experts HERE

This occurrence appears to have declined considerably from its peak last week, presumably because the migration has moved rapidly northwards. Already, reports from the eastern US Atlantic coast (e.g. Cape May) of a great shearwater influx are coming in, so we must hope that the attrition rate in the Northern Bahamas has stopped, or will stop within the next few days. This is evidenced by this FB clip from Tom Reed, a photographic contributor to THE BIRDS OF ABACO

TR clip

The ABA (American Birding Association) has taken an interest in the problem on Abaco, and reported the incidence of shearwater die-off HERE. For the sake of completeness, I have updated reports I have received or found over the last few days below, together with an updated distribution map. More sad images are included because, pitiful though they are, photographs are of real assistance in the study of migratory die-off. For example, it is likely that juvenile birds are more likely to be affected by exhaustion in the course of their 10,000 mile journey than adults. Photos enable an assessment of the age of the birds to be made.

Exhausted shearwater, Delphi beach. Is this a juvenile, less able to make a huge journey than an adult?Great Shearwater, Delphi, Abaco (Sharon Elliott)The yellow tip to this bird’s beak shows that it is a different species of shearwater, the Cory’s.  Like the Greats, these birds are also rare transients on Abaco, and also make long-distance migrations. A Cory’s was photographed a couple of weeks ago swimming happily off the Delphi beach. This one has obviously run out of stamina. It has the chance to recover, but it is vulnerable in this state; and turkey vultures are quick to move in on fatalities…

 UPDATED REPORTS (SINCE JUNE 24) IN RED
  • Delphi Club Beach – 20 plus + 1
  • Schooner Bay – 5
  • Bahama Palm Shores – ‘many many’ dead birds washed up on the shore
  • Casuarina Beach – 1
  • Cherokee (Watching Bay) – 3 or 4
  • Cherokee (Winding Bay) – 4
  • Little Harbour – 3
  • Marsh Harbour area – about 5
  • Great Guana Cay, southern end   – 1 (possibly a gull)
  • Tilloo Cay – 13 at least on Junk Beach, more than ever seen (see photos below)
  • Elbow Cay – 2 + 1 Atlantic side beach near Abaco Inn
  • Elbow Cay – 2, North End
  • Green Turtle Cay beach – 2
  • Green Turtle Cay, offshore – “a lot in the water”
  • Man-o-War Cay – 1 by the roadside
  • Ocean 20m from HT Lighthouse – 2 in the sea

also Exuma Sound (5 birds), Shroud Cay Exuma (gull?”), Briland Beach,Harbour Island Eleuthera (“some” + 4) , and Church Bay, South Eleuthera – 10 + 2

Ellen Bentz, who reported the Church Bay birds, has frozen 3 of them for research purposes; it will be extremely interesting to see what results from their examination, from the ages of the birds to condition to likely cause of death. She also took photographs to aid species identification and diagnostic efforts.

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Abaco distribution map. Earlier reports marked in green, two new sites in blue
Shearwater Map, Abaco update

Here is the wonderful Crossley ID guide tableau of great shearwaters, showing every facet of the birdGreat_Shearwater_from_the_Crossley_ID_Guide_Britain_and_Ireland
WHERE DO THESE BIRDS COME FROM & WHERE DO THEY GO?
Sean Giery of the excellent ABACO SCIENTIST has also commented on the recent phenomenon, concluding “…if you haven’t looked up Gough Island, the probable origin of these Greater Shearwaters, do. Use Google Maps to get an impression of how far these amazing birds travel. It’s truly amazing.” By great good fortune, I’ve done the legwork for you… Let’s take a closer look.
Great shearwaters breed almost exclusively the small area of the globe that includes the Gough Islands, Tristan da Cunha and a few lesser-known islands in that area. There is also a small breeding population in the Falklands. Whichever, they are not so very far from Antarctica. Their range, however, is massive and involves long migrations over the Atlantic ocean to the far north – as far as the Arctic – and back each year.
gtshearmap
 And, as the shearwater flies, this is the distance from the breeding grounds to Abaco; 2/3 of their total journey. Now, factor in a first-season juvenile shearwater facing the vagaries of food supply, weather conditions and stamina… The fact that some die-off occurs every few years at some stage of the migration becomes less surprising.
Gough Island to Abaco 6300 milesGough Island to Abaco jpg
I’ll conclude with a photo of a great shearwater flying ‘at the shear’, which I am certain is how best we’d like to think of these wonderful seabirds…
Great_Shearwater_RWD3b Dick Daniels
Credits: to the 30 or so people credited in the original post I add with thanks Molly Kemmer Roberts, Susan Drwal, Sharon Elliott, Ellen Bentz, Dick Daniels and open source maps chaps.

SHEARWATERS ON ABACO: SAD TALES FROM THE SEA


GREAT SHEARWATER Puffinus gravis (Patrick Coin Wiki)

SHEARWATERS ON ABACO: SAD TALES FROM THE SEA

We do not generally do sad or sombre at Rolling Harbour. It’s a beautiful and happy place, and the Delphi Club is a haven of good fellowship and good craic (stemming no doubt from its Irish connections). But I have to report on a sad occurrence on the beach at Delphi and, as it turns out, at many other Abaco locations (and beyond) during June – a notable number of shearwaters being found dying or dead on beaches or else in the sea, their bodies in due course being washed in on the tide.

There are quite a few species of shearwater worldwide, of which 5 are recorded for Abaco. The only permanent breeding resident is the Audubon’s Shearwater, a bird that is quite commonly seen out at sea though not, I imagine, on land. We never managed to obtain a photo of one for “The Birds of Abaco”. I presume there are breeding colonies on Abaco, but not that I have heard about.

Shearwater Checklist, Abaco

As the checklist above shows, three of the other shearwaters are rare transients. These birds fly long migration routes over the ocean and so the casual birder is in practice unlikely to encounter one, let alone get a photograph. The Manx can be ignored as an aberration – the V5 means that one or two vagrant individuals have been recorded since (say) 1950. Great Shearwater Puffinus gravis - Patrick Coin Wiki

My first inkling that something unusual was occurring came a week ago from a FB post by Melissa Maura, whose wonderful parrot and flamingo photos feature elsewhere in these pages. She said …on my rugged Abaco ocean beach last week, were many dead magnificent seabirds – greater shearwaters (about 5) and a couple of Frigate birds… They didn’t appear to wash in on the waves, but appeared to have perished perhaps from exhaustion on the beach”.  Various later comments suggested that this phenomenon had been noted periodically in the past, the last time 4 or 5 years ago. 

Great Shearwater (dec'), Abaco (Melissa Maura)

This was followed a couple of days later by evidence from well-known birding maestro Woody Bracey that living great shearwaters were in Abaco waters, perhaps confirming that they are in mid-migration at the moment. The one in #2 was “caught” 3 miles off Great Guana Cay.

Great Shearwater Abaco (Woody Bracey)Great Shearwater, Abaco boated (Woody Bracey)

Then a couple of days ago Jane Mantle emailed me with photos of some dead birds on the beach at Delphi saying that half- dead birds are washing up on the beach ‘only for the vultures to finish off’.  We must have over 20 with more to come”. I circulated these to the ‘usual suspects’ for ID and comment.

Great Shearwater, Abaco (dec'd) (Jane Mantle)Great Shearwater, Abaco (dec'd) (Jane Mantle)

I also posted the photos on my RH FB to see if others had seen anything similar. Many thanks to all those who ‘liked’, shared or commented on the post. Here is a summary of the responses, from which a pretty clear picture emerges of widespread recent shearwater deaths on Abaco mainland and Cays.

  • Delphi Club Beach – 20 plus
  • Bahama Palm Shores – ‘many many’ dead birds washed up on the shore
  • Casuarina Beach – 1
  • Cherokee (Watching Bay) – 3 or 4
  • Cherokee (Winding Bay) – 4
  • Marsh Harbour area – about 5
  • Great Guana Cay, southern end   – 1 (possibly a gull)
  • Tilloo Cay – 13 at least on Junk Beach, more than ever seen (see photos below)
  • Elbow Cay – 2 + 1 Atlantic side beach near Abaco Inn
  • Elbow Cay – 2, North End
  • Green Turtle Cay beach – 2
  • Green Turtle Cay, offshore – “a lot in the water”
  • Man-o-War Cay – 1 by the roadside
  • Ocean 20m from HT Lighthouse – 2 in the sea

also Exuma Sound (5 birds), Briland Beach Harbour Island (“some”) and Shroud Cay (gull?”)

SIGHTINGS MAP, ABACO AS AT 09.00 JUNE 25 (2X click to enlarge)
Shearwater Map, Abaco

Shearwaters at Tilloo Cay (Janie Thompson)

Great Shearwater (dec'd) Tilloo Cay Abaco988563_780040245445527_87776362163085216_n10429826_780040222112196_5624095942981629125_n

Shearwaters on Elbow Cay (Rudolf Verspoor)

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WHAT SORT OF SHEARWATERS ARE THESE?

In the main it looks and sounds as though these are migrating great shearwaters. Woody Bracey has identified several dead birds as ‘greats’ from photos, and one as an alive Cory’s shearwater swimming in the sea off the Delphi Beach. ID is not easy, and a few of the birds found may be gulls. It’s possible that there are some Audubon’s shearwaters among the stricken birds, although since they are resident to Abaco that would go against the theory of an exhausted migratory species that has been blown of course en masse.

Great Shearwater Puffinus gravis (JJ Harrison Wiki)

WHAT DO THE EXPERTS THINK?

There are a few obvious contenders for the solution to the riddle of the shearwaters, ranging from the frontrunner migration exhaustion to disease and trash ingestion. The evidence of mass deaths over a wide geographical area during a short time probably rules out trash ingestion – although I’m sure the poor creatures must have plenty of plastic bits inside them. Mass disease striking suddenly over one area is seems unlikely. Once those two possibilities are ruled out, the primary cause, covering most instances of the sad and upsetting phenomenon, becomes clearer.

Lynn Gape of BNT posted the view of William Mackin, a seabird biologist who looked at some of the photos and wrote “The five birds look like greater shearwaters. They breed at Gough Island in the South Atlantic. The young begin life by flying 10000 miles to Newfoundland in the North Atlantic. Some do not make it. They wash up on eastern US and Bahamian beaches. It is sad. We should monitor the numbers. The frequency is variable but possibly increasing.”

Tony White, the omniscient Recorder of Bahamas Birds and compiler of the comprehensive and authoritative checklist for the area, writes: 

“The dead birds on the beach (and in the water) is a phenomenon that happens every five to ten years. According to the late Dave Lee these are young Great Shearwaters migrating from their natal home in the South Atlantic to their feeding grounds off the US and Canada, Combination of poor food supply and wind conditions in the doldrums lead to their expending all their energy and expiring. It is a normal event for this species and has been recorded many times The Great Shearwater population appears to weather the bad years and do well in the good years. Relevant articles are: Lee, D.S. 2009. Mass die-offs of Greater Shearwater in the Western North Atlantic: Effects of weather patterns on mortality of a trans-equatorial migrant. Chat 73(2):37; Seabird Ecological Assessment Network. 2007. Greater Shearwater Die-off in the Atlantic: June-July 2007. Volunteer Newsletter 3(2):2; and Watson, George. 1970. A Shearwater Mortality on the Atlantic Coast.  Atlantic Naturalist 25(2):75-80.

Woody Bracey has now left an informative and perceptive comment: “It’s amazing how far(10,000 miles) these young birds have to travel to their feeding grounds so soon after being fledged. Breeding colonies are on isolated subantarctic islands of the southern hemisphere. Breeding begins in October. Incubation of the single egg lasts 55 days and it is another 105 days until the chick is ready to fly. Each loss of a bird represents much time and effort of a pair to produce a single chick which then has to fly the gauntlet through the windless, often foodless doldrums to reach its northern feeding grounds. So many hazards, so few birds! It’s sad to witness these die-offs but the species still survives. Global warming cannot be helping this species on its journey to the colder, nutrient rich more northern briny destinatioin. Lets stop setting our dumps and forests on fire here in the Abacos. Eventually it will not only affect the Great Shearwaters but us as well”.

I should add that it is reassuring to be able to confirm that, at least at present, the great shearwater is IUCN-listed “Least Concern”

Status_iucn3.1_LC.svg

Great Shearwater in flight (Hardaker)

Tony has asked for all available information Bahamas-wide: “It would be very useful if someone could collect some hard data on the die-off, e.g. when was it first noted and how many birds are found along a given stretch of beach? Check for other species and take a few wings as samples of the desiccated birds. In past events the number of dead birds was much greater on Crooked and Acklin Islands than Abaco. Eleuthera too should be checked if possible”.

Lynn has also asked “Please photograph and count birds found on your beaches and send images and the number counted to me at lgape@bnt.bs. We will send on to William Mackin and Tony White who are keeping records of these occurrences The image with this post is a Greater Shearwater in flight…” (see above, as we would all like to think of these magnificent birds)

Or by all means contact me at rollingharbour.delphi@gmail.com and I’ll pass on any info

STOP PRESS An update to this post written the following week, detailing new sightings and reporting the passing of a sad fortnight of shearwater fatalities in the Bahamas, can be found HERE

A happier great shearwater image to leave you with…
Great Shearwater (Dick Daniels, Wiki)
Credits and thanks to Woody Bracey, Melissa Maura, Lynn Gape, Jane Mantle, William Mackin, Patrick Coin, J J Harrison, Dick Daniels, Norvell Slezycki, Lory Kenyon, Selah Vie, Lindsey Delaphine McCoy, Turtle Cove Tilloo, Janie Thompson, Rudolf Verspoor, Laurie Schreiner, Caroline Woodson Sawyer, Steph Russell, Ashley L. Albury, Dwayne Wallas, Sully Vincent T Sullivan, Ben Albury, Abaco Bulletin, Carol Rivard Roberts, Jason McIntosh, Dale Sawyer, Barbara Trimmer, Dominique Allen, Jessica Aitken and Juana Rudzki, with apologies to anyone else who has slipped through the net…