Sterna bergii

Taxonomy

Assessment Information

Geographic Range

Habitat and Ecology

Threats

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Taxonomy [top]

Kingdom	Phylum	Class	Order	Family
ANIMALIA	CHORDATA	AVES	CHARADRIIFORMES	LARIDAE

Scientific Name:

Sterna bergii

Species Authority:

Lichtenstein, 1823

Common Name/s:

English	–	Crested Tern, Great Crested Tern, Great Crested-Tern, Greater Crested Tern, Swift Tern
French	–	Sterne huppée

Assessment Information [top]

Red List Category & Criteria:

Least Concern ver 3.1

Year Assessed:

2009

Assessor/s:

BirdLife International

Reviewer/s:

Bird, J., Butchart, S.

Justification:
This species has an extremely large range, and hence does not approach the thresholds for Vulnerable under the range size criterion (Extent of Occurrence <20,000 km2 combined with a declining or fluctuating range size, habitat extent/quality, or population size and a small number of locations or severe fragmentation). The population trend appears to be stable, and hence the species does not approach the thresholds for Vulnerable under the population trend criterion (>30% decline over ten years or three generations). The population size is very large, and hence does not approach the thresholds for Vulnerable under the population size criterion (<10,000 mature individuals with a continuing decline estimated to be >10% in ten years or three generations, or with a specified population structure). For these reasons the species is evaluated as Least Concern.

History:

2008	–	Least Concern
2004	–	Least Concern

Geographic Range [top]

Range Description:	This species can be found found on islands and coastlines of the tropical and subtropical Old World, ranging from the Atlantic Coast of South Africa, south around the Cape and continuing along the coast of Africa and Asia almost without break to south-east Asia and Australia. It can also be found on Madagascar, islands of the western Indian ocean and islands of the western and central Pacific Ocean. Outside the breeding season it can be found at sea throughout this range, with the exception of the central Indian Ocean¹.
Countries:	Native: Australia; Bahrain; Bangladesh; British Indian Ocean Territory; Brunei Darussalam; Cambodia; China; Cook Islands; Djibouti; Egypt; Eritrea; Fiji; French Polynesia; Guam; India; Indonesia; Iran, Islamic Republic of; Iraq; Israel; Japan; Kenya; Kiribati; Kuwait; Madagascar; Malaysia; Maldives; Marshall Islands; Mauritius; Mayotte; Mozambique; Myanmar; Namibia; New Caledonia; Northern Mariana Islands; Oman; Pakistan; Palau; Papua New Guinea; Philippines; Qatar; Saudi Arabia; Seychelles; Singapore; Solomon Islands; Somalia; South Africa; Sri Lanka; Sudan; Taiwan, Province of China; Tanzania, United Republic of; Thailand; Timor-Leste; Tonga; Tuvalu; United Arab Emirates; Vanuatu; Viet Nam; Wallis and Futuna; Yemen Vagrant: Jordan; Korea, Democratic People's Republic of; Nauru; New Zealand; United States
Range Map:	Click here to open the map viewer and explore range.

Habitat and Ecology [top]

Habitat and Ecology:	Behaviour Many populations of this species remain sedentary in their breeding areas or disperse locally¹ although some are more migratory². The species breeds in large dense colonies, or in small groups of less than 10 pairs amidst colonies of other species (e.g. King Gull Larus hartlaubii or Silver Gull Larus novaehollandiae)¹. It usually forages singly² or in small groups¹ but several hundred individuals may gather at roost sites³. Habitat The species inhabits tropical and subtropical coastlines, foraging in the shallow waters of lagoons^{1, 4}, coral reefs¹, estuaries^{1, 2}, bays, harbours and inlets⁴, along sandy, rocky, coral¹ or muddy shores, on rocky outcrops in open sea, in mangrove swamps³ and also far out to sea on open water¹. It shows a preference for nesting on offshore islands^{1, 2}, low-lying coral reefs, sandy or rocky coastal islets, coastal spits, lagoon mudflats¹, and artificial islets in saltpans and sewage works^{1, 2} within 3 km of the coast¹. Diet Its diet consists predominantly of pelagic fish 10-50 cm long^{1, 2} although it will also take cephalopods (e.g. squid), crustaceans¹ (e.g. crabs¹ and prawns⁴), insects and hatchling turtles opportunistically¹. Breeding site The nest is a shallow scrape in bare sand, rock or coral¹ in flat open sites² on offshore islands^{1, 2}, low-lying coral reefs, sandy or rocky coastal islets, coastal spits, lagoon mudflats¹ or islets in saltpans and sewage works^{1, 2}. The species nests in dense colonies² with neighbouring nests very close together (rims may be touching)¹, and usually forages within 3 km of the breeding colony¹.
Systems:	Terrestrial; Marine

Habitat and Ecology:

Behaviour Many populations of this species remain sedentary in their breeding areas or disperse locally¹ although some are more migratory². The species breeds in large dense colonies, or in small groups of less than 10 pairs amidst colonies of other species (e.g. King Gull Larus hartlaubii or Silver Gull Larus novaehollandiae)¹. It usually forages singly² or in small groups¹ but several hundred individuals may gather at roost sites³. Habitat The species inhabits tropical and subtropical coastlines, foraging in the shallow waters of lagoons^{1, 4}, coral reefs¹, estuaries^{1, 2}, bays, harbours and inlets⁴, along sandy, rocky, coral¹ or muddy shores, on rocky outcrops in open sea, in mangrove swamps³ and also far out to sea on open water¹. It shows a preference for nesting on offshore islands^{1, 2}, low-lying coral reefs, sandy or rocky coastal islets, coastal spits, lagoon mudflats¹, and artificial islets in saltpans and sewage works^{1, 2} within 3 km of the coast¹. Diet Its diet consists predominantly of pelagic fish 10-50 cm long^{1, 2} although it will also take cephalopods (e.g. squid), crustaceans¹ (e.g. crabs¹ and prawns⁴), insects and hatchling turtles opportunistically¹. Breeding site The nest is a shallow scrape in bare sand, rock or coral¹ in flat open sites² on offshore islands^{1, 2}, low-lying coral reefs, sandy or rocky coastal islets, coastal spits, lagoon mudflats¹ or islets in saltpans and sewage works^{1, 2}. The species nests in dense colonies² with neighbouring nests very close together (rims may be touching)¹, and usually forages within 3 km of the breeding colony¹.

Systems:

Terrestrial; Marine

Threats [top]

Major Threat(s):	The species is vulnerable to human disturbance (e.g. tourism) at breeding colonies on offshore islands⁶ which can lead to nest desertion and increased predation of eggs and nestlings by gulls and ibises⁷. The species is also threatened by injury and mortality from entanglement with baited hooks, fishing lines, nets and human refuse (e.g. plastic bags)⁷. Utilisation Most breeding colonies of this species are subject to subsistence egg collecting^{1, 5}.

Major Threat(s):

The species is vulnerable to human disturbance (e.g. tourism) at breeding colonies on offshore islands⁶ which can lead to nest desertion and increased predation of eggs and nestlings by gulls and ibises⁷. The species is also threatened by injury and mortality from entanglement with baited hooks, fishing lines, nets and human refuse (e.g. plastic bags)⁷. Utilisation Most breeding colonies of this species are subject to subsistence egg collecting^{1, 5}.

Citation:	BirdLife International 2009. Sterna bergii. In: IUCN 2011. IUCN Red List of Threatened Species. Version 2011.2. <www.iucnredlist.org>. Downloaded on 09 February 2012.
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