Agelaius xanthomus

Taxonomy

Assessment Information

Geographic Range

Population

Habitat and Ecology

Threats

Conservation Actions

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Taxonomy [top]

Kingdom	Phylum	Class	Order	Family
ANIMALIA	CHORDATA	AVES	PASSERIFORMES	ICTERIDAE

Scientific Name:

Agelaius xanthomus

Species Authority:

(Sclater, 1862)

Common Name/s:

English

–

Yellow-shouldered Blackbird

Taxonomic Notes:

Assessment Information [top]

Red List Category & Criteria:

Endangered B1ab(i,ii,iii,v) ver 3.1

Year Published:

2012

Assessor/s:

BirdLife International

Reviewer/s:

Butchart, S. & Symes, A.

Contributor/s:

Miranda-Medina, R.

Justification:
This species has a very small, fragmented and declining range. An ongoing conservation programme has substantially improved its status but, until habitat loss is halted, the species will continue to qualify as Endangered.

History:

2008	–	Endangered
2004	–	Endangered
2000	–	Endangered
1996	–	Endangered
1994	–	Endangered

Geographic Range [top]

Range Description:	Agelaius xanthomus was formerly widespread on Puerto Rico (to USA), where it occurs in two forms. The race monensis is found throughout the offshore islands of Mona and Monito. The nominate race occurs on the mainland, but is now mostly restricted to south-west coastal areas. There is also a population in eastern coastal areas, but this has almost vanished, with no breeding records since 1986 (USFWS 1996c,d). The south-west population declined by c.80% in 1975-1981 to a low of 300 individuals in 1982, but pre-reproductive season roost counts in 1985-1995 showed an average annual increase of 14% (USFWS 1996c,d); by 2011 there were 850 individuals, with an additional 60 at Salinas (R. Miranda-Medina in litt. 2012). In early 1998, the total population was estimated at 1,250 individuals (Jaramillo and Burke 1999).
Countries:	Native: Puerto Rico
Range Map:	Click here to open the map viewer and explore range.

Population [top]

Population:	Jaramillo and Burke (1999).
Population Trend:	Decreasing

Habitat and Ecology [top]

Habitat and Ecology:	It formerly occurred in mangroves, pastures, coconut and palm-stands, cactus scrub, coastal cliffs, and rarely woodland, and has always been commonest near the coast (Jaramillo and Burke 1999). Many birds now breed on offshore cays (Skutch 1996). It forages both terrestrially and in trees (Skutch 1996), feeding on insects (especially moths and crickets), seeds and nectar (Raffaele et al. 1998). Birds gather at communal feeding-sites, with large flocks forming during the non-breeding season (Jaramillo and Burke 1999). Nests are often built low in mangrove trees, or in large deciduous trees in pastures near to mangroves (Skutch 1996), with several nests being built in close proximity (Jaramillo and Burke 1999). On Mona Island, nests are placed in crevices or on ledges on high, vertical sea-cliffs (Skutch 1996). Three clutches are usually laid per year (Skutch 1996), and the breeding season is May-September.
Systems:	Terrestrial

Habitat and Ecology:

It formerly occurred in mangroves, pastures, coconut and palm-stands, cactus scrub, coastal cliffs, and rarely woodland, and has always been commonest near the coast (Jaramillo and Burke 1999). Many birds now breed on offshore cays (Skutch 1996). It forages both terrestrially and in trees (Skutch 1996), feeding on insects (especially moths and crickets), seeds and nectar (Raffaele et al. 1998). Birds gather at communal feeding-sites, with large flocks forming during the non-breeding season (Jaramillo and Burke 1999). Nests are often built low in mangrove trees, or in large deciduous trees in pastures near to mangroves (Skutch 1996), with several nests being built in close proximity (Jaramillo and Burke 1999). On Mona Island, nests are placed in crevices or on ledges on high, vertical sea-cliffs (Skutch 1996). Three clutches are usually laid per year (Skutch 1996), and the breeding season is May-September.

Systems:

Terrestrial

Threats [top]

Major Threat(s):	Brood-parasitism by Shiny Cowbird Molothrus bonariensis has greatly reduced numbers and resulted in most birds breeding on offshore cays. Additional threats are the competition for nesting areas by Caribbean Martin Progne dominicensis, habitat loss clearance for agriculture, nest-predation by the Pearly-eyed Thrasher Margarops fuscatus and elevated mortality by introduced carnivores such as Indian Mongoose (Herpestes auropunctatus).

Major Threat(s):

Brood-parasitism by Shiny Cowbird Molothrus bonariensis has greatly reduced numbers and resulted in most birds breeding on offshore cays. Additional threats are the competition for nesting areas by Caribbean Martin Progne dominicensis, habitat loss clearance for agriculture, nest-predation by the Pearly-eyed Thrasher Margarops fuscatus and elevated mortality by introduced carnivores such as Indian Mongoose (Herpestes auropunctatus).

Conservation Actions [top]

Conservation Actions:	Conservation Actions Underway A programme installing artificial nests, monitoring reproduction and controlling populations of Molothrus bonariensis, rats and nest-mites has operated since 1982 (USFWS 1996c,d). The Boquerón Commonwealth Forest is a stronghold for the species on the mainland (Jaramillo and Burke 1999). Conservation Actions Proposed Continue to protect and manage the species and its habitat, including the provision of artificial nests and control of Shiny Cowbirds (USFWS 1996c,d). Monitor the success of artificial nests (USFWS 1996c,d). Integrate the conservation of this species with existing education schemes (USFWS 1996c,d).

Conservation Actions:

Conservation Actions Underway
A programme installing artificial nests, monitoring reproduction and controlling populations of Molothrus bonariensis, rats and nest-mites has operated since 1982 (USFWS 1996c,d). The Boquerón Commonwealth Forest is a stronghold for the species on the mainland (Jaramillo and Burke 1999).

Conservation Actions Proposed
Continue to protect and manage the species and its habitat, including the provision of artificial nests and control of Shiny Cowbirds (USFWS 1996c,d). Monitor the success of artificial nests (USFWS 1996c,d). Integrate the conservation of this species with existing education schemes (USFWS 1996c,d).

Citation:	BirdLife International 2012. Agelaius xanthomus. In: IUCN 2012. IUCN Red List of Threatened Species. Version 2012.2. <www.iucnredlist.org>. Downloaded on 22 May 2013.
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