BAHAMA ORIOLE: HABITAT FIND FOR A RARE GEM

March 12, 2019 by Rolling Harbour

BAHAMA ORIOLE: HABITAT FIND FOR A RARE GEM

RARE, PRECIOUS – AND FOUND ONLY ON ANDROS, BAHAMAS

The future of the gorgeous endemic Bahama Oriole (Icterus northropi) hangs in the balance. IUCN Red Listed as ‘Critically Endangered’, the Oriole once lived on both Abaco and Andros. As recently as the 1990s, the species became extirpated on Abaco, leaving a small and fragile population in fairly specific areas of Andros. These are places where the habitat is conducive to the orioles’ well-being, and in particular where they can safely breed and (with luck) replenish their depleted population.

We hear a lot about habitat loss as a grave worldwide problem for an increasing number of species. Narrow that down to one species, one island, a few defined areas, then add mankind and his needs to the mix. The wrong mix of habitat degradation, clearances, predation or disease could cause the Andros population to disappear as well.

Which is where conservation and science come into play. The Bahamas archipelago benefits from an astonishing number of (broadly-speaking) environmental organisations that are involved in species and habitat protection, both terrestrial and marine. They range from international to Bahamas-wide and Governmental, to NFP organisations on the main islands, and on through local communities via citizen scientists to dedicated individuals. All are fighting a specific battle with a single aim; all face an increasing array of metaphorical weapons being deployed against them.

SO, ANY GOOD NEWS THEN?

Returning to the orioles – in many ways a perfect indicator bird species – recent research has led to an encouraging discovery. A new study in The Journal of Caribbean Ornithology published by researchers from the University of Maryland, Baltimore County and Bahamas National Trust collaborating on the Bahama Oriole Project (@BahamaOrioleProject) reveals new evidence about the nesting habits and habitats of the orioles that will have “…major implications for future conservation” (this work was funded in part by the American Bird Conservancy and Birds Caribbean).

The study is the outcome of the work of a dozen conservation specialists. In a coconut-shell, the orioles were thought to nest only in the coconut palms found near the coast. However the recent intensive research program reveals that ‘multiple pairs’ breed in the pines and the thatch palms of the forests, away from the coast. Indeed, these may prove to be the primary nesting locations. The implications of these new findings are significant, not least for a possible uplift in numbers and the way in which conservation measures can be adapted to the new discovery. For those wanting something more authoritative, the short Abstract of the study is given at the end. And if you’d like to read the whole article, click on the link below.

472-Article Text-1543-1-10-20180828

THE MAIN CAUSES OF THE CRITICAL DECLINE ON ANDROS

Lethal Yellowing Disease of the coastal coconut palms, until very recently (see above) believed to be the prime nesting habitat for the oriole. In some areas the palms have been all but wiped out. The recent findings in the forests have clearly reduced the impact of this specific problem
The arrival in the 1990s and spread of the Shiny Cowbird Molothrus bonariensis, a brood parasite that lays its eggs in the nests of other bird species*
Habitat loss / development
Forestry work / forest fires
Feral cats and rodents
Disease within the population is also cited as a contributory cause

*The date of this arrival seems to correspond to when the orioles were extirpated from Abaco. However, see next para.

WHEN & WHY DID THE ORIOLES VANISH FROM ABACO?

This is a classic ‘riddle wrapped in a mystery inside an enigma’. Various sources I have looked at use a formula such as “…became extirpated from Abaco in the 1990s”, or “disappeared for unknown reasons in the 1990s”. However, Abaco birding expert Elwood ‘Woody’ Bracey comments (see below) that Bahama Orioles were last formally recorded on Abaco in 1973 by researcher Duncan Everette and his partner who were banding warblers in Southern Abaco in what is now the Abaco National Park. At that time, the Shiny Cowbird was only rarely found on Abaco, if at all.

I’ve found no clear clue as to the cause – nor even when the last evidences sighting of an oriole on Abaco was made. I haven’t found a single photo of one taken on Abaco at any time in history. To be fair the option of snapping everything with wings multiple times using a digital camera with a huge chip didn’t exist then. As to past history, Kevin Omland of @BahamaOrioleProject says that there are at least 9 specimens in museums around the world collected from Abaco in the 1800s and early 1900s.

eBird map showing Bahama Oriole sightings distribution in c21

ABSTRACT

The Bahama Oriole (Icterus northropi) is a Critically Endangered species endemic to The Bahamas and currently found only on the Andros island complex. With the elevation of the Bahama Oriole to full species status in 2011, research suggested that there were fewer than 300 individuals remaining in the global population. The Bahama Oriole was also termed a “synanthropic species” based on data suggesting that the species nested almost exclusively within anthropogenic residential and agricultural habitats in introduced coconut palms (Cocos nucifera). These conclusions were based on population surveys primarily confined to settled areas near the coasts. However, we documented multiple pairs of orioles with breeding territories deep in pine forests, and we present the first records of Bahama Orioles nesting in pine forests—in both a Caribbean pine (Pinus caribaea) and native understory Key thatch palms (Leucothrinax morrisii). Given the predominance of the pine forests on Andros, this newly documented breeding habitat has important implications for developing population estimates and future conservation plans for the Bahama Oriole.

640px-Picture_of_John_Isaiah_Northrop Bahama Oriole Stamp birdtheme.org Credits: Dan Stonko / American Bird Conservancy, Michael Baltz / Bahama Oriole Project / Kevin Omland; Mary Kay Beach; Bahama Oriole Project FB header; C Ward / BNT; Thomas Nierle / Bahama Oriole Project; Bahamas Postal Service; BNT; D Belasco / American Bird Conservancy; Handbook of World Birds (drawing)

↑ Mr Northrop with his Bird

WOOD STORKS ON ABACO? CLOSE BUT NOT CLOSE ENOUGH…

September 9, 2015 by Rolling Harbour

WOOD STORKS ON ABACO? CLOSE BUT NOT CLOSE ENOUGH…

I very rarely write about birds that you can’t find on Abaco, especially ones that have never been recorded there. In fact, I don’t think I have ever done so. The nearest was the critically endangered endemic BAHAMA ORIOLE, until quite recently available on Abaco. For the familiar and depressing reasons it was deemed extirpated in the 1990s and is found now only in very specific area of Andros. Its future is very uncertain: another species a feather’s width from extinction.

Which brings me to the Wood Stork Mycteria americana, a fine bird with a breeding population in Florida. Yet the last one recorded for the Bahamas was 51 years ago – and not on Abaco. It’s surprising that the species is not driven across the stretch of sea to the northern Bahamas by curiosity or more plausibly by storms (as with other vagrant species).

The first Bahamas sighting of a Wood Stork since 1964 occurred on September 4th at the unromantic-sounding ‘Freeport Dump’ on Grand Bahama, when naturalist and birding guide Erika Gates found one. The bird was still there on September 7th when Woody Bracey flew over from Abaco and joined Erika to check. Here it is.

Woody took a date-stamped shot for future reference

The distance from Freeport to Marsh Harbour, Abaco is about 100 miles as the stork flies. But from the eastern end of Grand Bahama to the nearest point on Abaco is much closer – 35 miles or so. So with a following wind perhaps it won’t be another 51 years until the next Wood Stork is seen in the Bahamas. And maybe next time it will fly as far as Abaco…

I sometimes feature photos by Florida photographer PHIL LANOUE, whose website is a must for anyone with an interest in birds. Among his specialities are the wood storks in his area, and I have chosen 4 outstanding WS images to end with (thanks as always to Phil for use permission).

Credits: Erika Gates, Woody Bracey, Phil Lanoue, ‘Huhnra’, Mehmet Karatay, ‘Googie Man’

BAHAMA ORIOLE: ABACO’S LOST ENDEMIC SPECIES

December 5, 2014 by Rolling Harbour

BAHAMA ORIOLE: ABACO’S LOST ENDEMIC SPECIES

FEWER THAN 300 LEFT IN THE WORLD – AND ALL ON ANDROS

Having just posted about the endangered NASSAU GROUPER and its protection by the introduction of a 3-month closed season, it’s time to focus on a rare, beautiful and vulnerable bird, the Bahama Oriole (Icterus northropi). It is IUCN Red Listed as ‘Critically Endangered’. ENDEMIC to the Bahamas, this bird lived only on Abaco and Andros. Not any more. Now you’ll only find them on Andros, the species having been lost to Abaco in very recent memory. The 1990s, in fact. And on Andros, this lovely bird is now struggling against the threat of extinction and is found only in limited areas in very small numbers. The most optimistic population estimate I have found puts the total as fewer than 300 individuals… the consensus puts the likely total in the region of 250. Bahamas Oriole, Andros (Binkie Van Es)1

THE SPECIES

In 2010, the Greater Antillean Oriole Icterus dominicensis was separated by the AMERICAN ORNOTHOLOGISTS’ UNION into 4 species, one being the Bahama Oriole. As the BNT wryly put it, “New species are always a source of excitement… but in this case the intrigue is overshadowed by a sense of alarm and urgency”. For by then this new species ‘in its own right’ was limited to certain parts of Andros, in small and diminishing numbers. It had already vanished from some areas – especially in North Andros – were it had formerly been abundant. The best estimates suggested 250 individual birds.

WHEN & WHY DID THEY VANISH FROM ABACO?

This is a classic ‘riddle wrapped in a mystery inside an enigma’. Various sources I have looked at use a formula such as “…became extirpated from Abaco in the 1990s”, or “disappeared for unknown reasons in the 1990s”. I’ve found no clear clue as to the cause – nor even when the last sighting of an oriole on Abaco was made. I haven’t found a photo of one taken on Abaco, although to be fair the option of snapping everything with wings several times using a digital camera with a large chip didn’t exist then. In the next para a number of crucial factors in the more recent decline of the Andros population are given; but as far as I can determine, some at least did not apply in the 1990s, or certainly not to the same extent. Maybe it was a combination of a degree of habitat loss and the gradual decline of a small population that could not breed prolifically enough to sustain the future population **. Bahama_Oriole (Mxmerce Wiki)

THE MAIN CAUSES OF THE CRITICAL DECLINE ON ANDROS

Lethal Yellowing Disease of the coconut palm, prime nesting habitat for the oriole. In some areas on Andros (e.g. Staniard Creek), the palm has been all but wiped out.

The arrival and spread of the Shiny Cowbird Molothrus bonariensis, a brood parasite that lays its eggs in the nests of other bird species such as the yellow warbler, the black-whiskered vireo… and the oriole. The cowbird reached Andros in the mid-1990s. The first Abaco report that I have found is from 1999 (so presumably, as the oriole was already gone from the island by then, they were not a factor). The cowbird is a summer resident on Abaco, though still relatively uncommon; and its range continues to expand northwards. Some might argue that the cowbird should be discouraged from spreading on Abaco right now for the sake of the indigenous warbler and vireo populations – before it is too late.

Habitat loss / island development (although Birdlife International notes “…the planting of coconut palms in residential areas has allowed the species to spread into human settlements”). Other factors put forward include forestry work, forest fires, diseases, rodents and feral cats – problems that affect many other birds such as the Abaco parrot. Bahamas Oriole (BNT / Carlton Ward) The photo below is a pleasure to include in this post. It was taken earlier this year on Andros by Christopher Johnson of Nassau. And here’s the thing. He is 13, and an avid birder. I’m sure he likes his X-Box time, but he certainly knows plenty about birds too. He’s quick off the mark with offering IDs – correct ones – for birds online, and when he saw this bird he knew the significance of it and managed to get some good shots too. This is my favourite, the oriole ‘vocalising’. See below for its song. Here is Christopher’s brief but enthusiastic field report: “Awesome trip to Andros this past weekend! Was amazed to see the Bahama Oriole and its nest — feeling great”.

Bahama Oriole taken during a BMMRO research trip on Andros

Paul Driver / Xeno Canto

A GLIMMER OF HOPE?

In the same way that urgent conservation measures were put in place to halt and then reverse the critical decline of the Abaco parrot population, similar projects are in place for the Bahama Oriole on Andros. One proposal is to establish a ‘captive breeding’ program leading to reintroduction and reinforcement of the wild population. According to the American Bird Conservancy, this could even include reintroduction on Abaco… So perhaps in a decade or two, this fine bird will once again become firmly established as one of the birds of Abaco. Bahamas Oriole, Andros (Binkie Van Es)3 As I said in my Nassau Grouper post, a country’s attitude can to a degree be gauged by the pride with which it features its wildlife and natural resources in its stamps (I used North Korea for adverse comparison). In 2009 The Bahamas Postal Service even issued a ‘Rare Birds’ set featuring the Bahama Oriole.. I rest my case. Bahama Oriole Stamp birdtheme.org

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WHO WAS THE EPONYMOUS MR NORTHROP?

640px-Picture_of_John_Isaiah_Northrop

The comprehensive answer is provided by the University of Glasgow Library Research Annexe in relation to a fine illustration from A Naturalist in the Bahamas (1910), reprinted in The Auk journal (below) at a time when Icterus northropi was still a mere subspecies: The yellow and black Bahama Oriole (Icterus Northropi) is a bird species unique to the Bahamas. The bird was named for American ornithologist and zoologist, John Isiah Northrop (1861–91); the illustration comes from an account of the trip Northrop and his botanist wife, Alice, took to the Bahamas in 1889 which was published in his memory: A Naturalist in the Bahamas: John I. Northrop, October 12 1861-June 25, 1891; a memorial volume (New York: Columbia University Press, 1910). It was edited and introduced by Henry Fairfield Osborn, professor of zoology at Columbia University where Northrop worked as a tutor and was killed in a laboratory explosion shortly (9 days) before the birth of his son John Howard Northrop (who became a Nobel prize-winning chemist).

RELATED MATERIAL

“Rediscovering the Bahama Oriole” Erik Gauger, author of the excellent Notes from the Road and photographic contributor to the Birds of Abaco has a good tale of the pursuit of the apparent sighting of a Bahama Oriole on Abaco 2o years after its (supposed?) extirpation. You can read it HERE The Auk Read more about this journal and the birding history of the Bahamas HERE There is a Care2Action ‘Save the Bahama Oriole Before It Is Too Late’ petition HERE. It seems to have stalled somewhat, so it would be good to generate some more signatories. ** Mathematically inclined? Find out about the application of the stochastic process to the oriole’s situation. In a nutshell, this concerns the combined effect of several random adverse factors on sustainability, given that the oriole’s already very small population, very limited range and particular habitat requirements militate against breeding expansion, and therefore increase the likelihood of extinction. We can only hope this is not an inevitability…

Image, audio and research credits: American Bird Conservancy, Binkie van Es, BNT / Carlton Ward, Birdlife International, Christopher Johnson, Cornell Neotropical, Harold Brewer, MxMerce, birdtheme.org, Wiki, Xeno Canto / Paul Driver; Uni of Glasgow / Roger Herriott