Phalacrocorax nigrogularis | UAE National Red List of Birds
Taxa
Phalacrocorax nigrogularis | Ogilvie-Grant & Forbes, 1899
Publication
Asessment status in full
Vulnerable
Assessment status abreviation
VU
Assessment status criteria
B2ab(iii)
Assessment rationale/justification
This species has a large breeding population in the UAE, with the largest breeding population, on Siniya Island (Umm Al Quwain), stable. The colonies in Abu Dhabi Emirate are potentially stable, although sub-populations are mobile between years, and the number of individual active colonies also seems to vary from year to year, with a past decline in the number of islands used, with Khan et al. (2018) reporting eight islands in Abu Dhabi Emirate.The species potentially occupies a very small area during the breeding season, and the area of occupancy (AOO) of breeding colonies may be as low as 36 km<sup>2</sup>), and it is precautionarily thought that each breeding island should be considered one location, inferred to be undergoing continuing declines in habitat quality and extent due to the potential for disturbance by people and disturbance and predation by animals, e.g. rats, foxes, dogs and cats. Therefore, the species is assessed here as Vulnerable under criterion B2ab(iii). Ongoing monitoring is essential for this species, and protection of active and potential nesting sites required.The non-breeding population appears to be in decline, potentially at a rate that would warrant listing as Vulnerable under criterion A; but the breeding population takes precedence hence the final listing as Vulnerable under criterion B2.
Assessment year
2019
Assessors/contributors/reviewers listed
UAE National Red List Workshop
Affliation of assessor(s)/contributors/reviewers listed on assessment
Government
IGO
Assessor affiliation specific
Government|IGO
Criteria system specifics
IUCN v3.1 + Regional Guidelines v4.0
Criteria system used
IUCN
Criteria Citation
IUCN. 2012. IUCN Red List Categories and Criteria: Version 3.1, Second edition. IUCN, Gland, Switzerland and Cambridge, UK. iv + 32pp pp. And IUCN. 2012. Guidelines for Application of IUCN Red List Criteria at Regional and National Levels: Version 4.0. Gland, Switzerland and Cambridge, UK: IUCN. iii + 41pp.
Endemic to region
Not_assigned
Endemism Notes
Is an endemic?: Not_assigned
Threats listed in assessment
Coastal development and disturbance on breeding islands is likely the greatest threat to the species, with detrimental effects in the past, present and future (BirdLife International 2010). Frequent human disturbance flushes parenting birds from nests, resulting in widespread egg and chick predation by gulls Larus spp. (Gallagher et al. 1984, Symens et al. 1993, Aspinall 1996). Total colony abandonment also occurs, and is not always followed by successful relocation elsewhere (Gallagher et al. 1984, Symens et al. 1993, Aspinall 1996). The extinction of 12 colonies since the 1960s is attributed to encroachment by development and prolonged human disturbance (H. King in litt. 2005). A current proposal to build a large multi-use project on Siniya Island (at present supporting a stable colony of c. 25,000 breeding pairs) including a bridge to the mainland, is likely to see the loss of this colony as a result of disturbance and subsequent access of terrestrial predators (S. Muzaffar in litt. 2016). Parent cormorants tend to respond to threats by departing from the nest rather than defensive aggression, leaving the chicks vulnerable to predation. In 2011, reports suggests that three Feral Cats Felis catus and three Red Foxes Vulpes vulpes were alone responsible for the death of c. 2,000 birds. The island has the capacity to sustain far larger predator populations, and there is potential for future increases in predation pressures. Simulated population models under these predation levels predict declines to near-extinction levels (a few hundred individuals) within 30 years (Muzaffar et al. 2013). As a ground-nesting species, Socotra Cormorant is vulnerable to the effects of storms, such as the flooding of nests during heavy rains, as took place on Suwad in November 1997. Similarly, in April 2003, an isolated thunderstorm with strong winds resulted in sudden termination of breeding and mass abandonment of chicks (H. King in litt. 2005). The species is highly vulnerable to marine oil spills (Gallagher et al. 1984, Symens and Suhaibani 1993). For instance, in August 1980 an oil spill of about 20,000 barrels off the coast of Bahrain killed up to 1,000 birds, most of which were Socotra Cormorants (Baha El Din 1991). Apart from direct mortality, effects include reduced immune function and reduced breeding success from oiling and ingestion, and depletion of prey fish stocks (Baha El Din 1991). As a piscivore, the species is susceptible to other marine pollutants such as heavy metals and PCBs (Polychlorinated biphenyls) as well as neurotoxins (Baha El Din 1991). The species suffers minor effects from competition with fisheries, including non-targeted capture of prey species or their use as baitfish (Muzaffar et al. 2017b). The diet of chicks varied significantly between years, suggesting that the species is a generalist and feeds opportunistically on abundant fish species (Muzaffar et al. 2017b). Persecution, as well as chick and egg collection at remaining breeding sites, poses a threat of unknown severity (Aspinall 1996, Environment Agency - Abu Dhabi 2016, Muzaffar et al. 2017a).
Conservation Measures
Conservation measures:
Conservation measures notes:
Required conservation measures:
History
In 1996 it is assessed that the species bred on >>10 islands (Khan et al.;2018), but there has been a steady loss of sites occupied for breeding over the intervening years. This is as a result of threats such as development, anthropogenic disturbance, predation and disturbance by animals and egg collection. The species thus now qualifies for listing as Vulnerable, whereas in 1996 it would have been listed as Near Threatened.
Scientific Name | Kingdom | Phylum | Class | Order | Family | Genus |
---|---|---|---|---|---|---|
Phalacrocorax nigrogularis | Animalia | Chordata | Aves | Suliformes | Phalacrocoracidae | Phalacrocorax |