BAHAMA ORIOLE: HABITAT FIND FOR A RARE GEM
c300 LEFT IN THE WORLD – AND ALL ON ANDROS
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, and a tiny, barely sustainable population, then add mankind and his needs to the mix. Not much habitat degradation, clearances, predation or disease is needed to reduce 300 specimens to zero.
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. The American Bird Conservancy (@ABCbirds) has just published the results of a new study in The Journal of Caribbean Ornithology. This involved several organisations – Bahamas National Trust, the Bahama Oriole Project (@BahamaOrioleProject), UMBC Biology, and Birds Caribbean. It concerns new evidence about the nesting habits and habitats of the orioles that will have “…major implications for future conservation”.
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. 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.
THE MAIN CAUSES OF THE CRITICAL DECLINE ON ANDROS
- Lethal Yellowing Disease of the coconut palms, prime nesting habitat for the oriole. In some areas the palms have been all but wiped out.
- 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 has also been mentioned (but I haven’t actually pursued the specifics…)
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”. 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 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.
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.
Credits: Dan Stonko / American Bird Conservancy, Michael Baltz / Bahama Oriole Project; 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