Bahama Oriole

Bahama Oriole

The Bahama Oriole (Icterus northropi) is a medium-sized bird found only on the island of Andros, making it an endemic species to The Bahamas. The Bahama Oriole is also classified by the International Union for Conservation of Nature (IUCN) as Critically Endangered, which they define as “[having] no subpopulation numbers more than 50 mature individuals” or “if at least 90% of individuals are in one subpopulation” (IUCN 2001). The Bahama Oriole’s scientific name comes from the couple who originally documented the species on Andros, the Northrops, who collected and described nine specimens of the bird in 1890. The Bahama Oriole (also called the coconut bird) is quite easy to identify: with its black head and body and lemon-yellow underside and wing linings, there aren’t any other birds in The Bahamas that even closely resemble it. The Bahama Oriole has a very interesting history of taxonomic identification. Originally classified as its own species (Allen 1890), the Bahama Oriole was amalgamated with four other regional species of oriole as the same species, called the Greater Antillean Oriole (Icterus dominicensis). Other researchers (including notable ornithologist James Bond) also considered the oriole found in The Bahamas a different species due to its significantly shorter and bulkier bill, but ultimately decided against it. It remained that way for many years, until recently, when morphological and genetic work as well as song analysis was done to show that the orioles found on the islands of Andros, Cuba, Hispaniola, and Puerto Rico all differed enough to be considered endemic to each island (Garrido, Wiley & Kirkconnell 2005). However this species distinction also meant that the Bahama Oriole was automatically considered Critically Endangered, as it had the smallest population of the four species.

Historically, the Bahama Oriole was found on both Abaco and Andros, but the Abaco population mysteriously disappeared during the 1990s, perhaps due to Hurricane Andrew. The current population is found throughout Andros and is estimated to be less than 250 individuals (Price 2011). Research has suggested that the birds use disturbed (human-altered) habitat during the breeding season, especially farms and residential areas but they also seem to require that their natural habitat, broadleaf coppice, is nearby year- round (Price & Hayes 2011). Bahama Orioles can also be found in mixed pine forests and pine forests (Omland 2016).

The Bahamas Oriole makes its nests on the undersides of palm tree fronds, and nests have been found on coconut palms (Cocos nucifera), Sabal palms (Sabal palmetto), and thatch palms (Leucothrinax morrisii). Orioles tend to nest on the tallest palm available to them, which, of the three species, is the coconut palm. That said, this is also possibly a reason their population is so small; lethal yellowing disease has decimated the once robust population of coconut trees on North Andros. With a large portion of nesting trees gone, the breeding population of North Andros has been decreased. This is supported by the fact that South Andros and Mangrove Cay have not been affected by lethal yellowing and so have healthier palm populations and higher densities of Bahama Orioles (Price & Hayes 2011).

Another threat to the oriole is the Shiny Cowbird (Molothrus bonariensis). The cowbird is a brood parasite, meaning that pregnant cowbird females will lay eggs in oriole nests, the orioles will hatch and raise the chick, which will grow faster and larger than the real offspring, and kick them out of the nest. The Bahama Oriole was found to be susceptible to brood parasitism by the Shiny Cowbird (Price & Hayes 2011), although not nearly as susceptible as its Puerto Rican relative (Icterus portoricensis; Wiley 1985). Other threats to the oriole include human impact such as deforestation and development, and invasive predators such as raccoons and cats.

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