Saunders's tern (''Sternula saundersi''), sometimes known as the black-shafted tern, is a species of

bird Birds are a group of warm-blooded vertebrates constituting the class (biology), class Aves (), characterised by feathers, toothless beaked jaws, the Oviparity, laying of Eggshell, hard-shelled eggs, a high Metabolism, metabolic rate, a fou ...

in the family Laridae. It is sparsely resident along the shores of the north-western

Indian Ocean The Indian Ocean is the third-largest of the world's five oceanic divisions, covering or approximately 20% of the water area of Earth#Surface, Earth's surface. It is bounded by Asia to the north, Africa to the west and Australia (continent), ...

(namely southern

Somalia Somalia, officially the Federal Republic of Somalia, is the easternmost country in continental Africa. The country is located in the Horn of Africa and is bordered by Ethiopia to the west, Djibouti to the northwest, Kenya to the southwest, th ...

Arabian Peninsula The Arabian Peninsula (, , or , , ) or Arabia, is a peninsula in West Asia, situated north-east of Africa on the Arabian plate. At , comparable in size to India, the Arabian Peninsula is the largest peninsula in the world. Geographically, the ...

Socotra Socotra, locally known as Saqatri, is a Yemeni island in the Indian Ocean. Situated between the Guardafui Channel and the Arabian Sea, it lies near major shipping routes. Socotra is the largest of the six islands in the Socotra archipelago as ...

Pakistan Pakistan, officially the Islamic Republic of Pakistan, is a country in South Asia. It is the List of countries and dependencies by population, fifth-most populous country, with a population of over 241.5 million, having the Islam by country# ...

Andaman and Nicobar Islands The Andaman and Nicobar Islands is a union territory of India comprising 572 islands, of which only 38 are inhabited. The islands are grouped into two main clusters: the northern Andaman Islands and the southern Nicobar Islands, separated by a ...

and northern

Sri Lanka Sri Lanka, officially the Democratic Socialist Republic of Sri Lanka, also known historically as Ceylon, is an island country in South Asia. It lies in the Indian Ocean, southwest of the Bay of Bengal, separated from the Indian subcontinent, ...

). It is a close relative of the

little tern The little tern (''Sternula albifrons'') is a seabird of the family Laridae. It was first described by the German naturalist Peter Simon Pallas in 1764 and given the binomial name ''Sterna albifrons''. It was moved to the genus '' Sternula'' whe ...

least tern The least tern (''Sternula antillarum'') is a species of tern that breeds in North America and locally in northern South America. It is closely related to, and was formerly often considered conspecific with, the little tern of the Old World. Oth ...

, yellow-billed tern, and Peruvian tern. In non-breeding plumages, the Saunder's tern and the little tern may be almost indistinguishable. The two have been considered by some to be

conspecific Biological specificity is the tendency of a characteristic such as a behavior or a biochemical variation to occur in a particular species. Biochemist Linus Pauling stated that "Biological specificity is the set of characteristics of living organism ...

Description

Saunders's tern shares many of the features of its close relative, the

, including a white body, a black-tipped yellow bill, and a black cap with a white forehead patch. In its breeding

plumage Plumage () is a layer of feathers that covers a bird and the pattern, colour, and arrangement of those feathers. The pattern and colours of plumage differ between species and subspecies and may vary with age classes. Within species, there can b ...

, it distinguishes itself with a straight-bordered forehead patch, possessing more black outer

primaries Primary elections or primaries are elections held to determine which candidates will run in an upcoming general election. In a partisan primary, a political party selects a candidate. Depending on the state and/or party, there may be an "open pri ...

, and duskier colored legs and feet in comparison to the bright yellow legs of the little tern. In non-breeding plumage, the two are very similar. Saunders's tern is 20–28 cm (8-11 in) long, weighs 40-45 grams, and possesses a

wingspan The wingspan (or just span) of a bird or an airplane is the distance from one wingtip to the opposite wingtip. For example, the Boeing 777–200 has a wingspan of , and a wandering albatross (''Diomedea exulans'') caught in 1965 had a wingsp ...

of 50-55 cm(20-21 in). It has an average wing length of 16.6 cm(6.5 in), an average bill length of 2.8 cm(1.1 in), and a tail fork depth of about 2.8 cm(1.1 in) on average.

Taxonomy

Saunders's tern was first described in 1877 by

British British may refer to: Peoples, culture, and language * British people, nationals or natives of the United Kingdom, British Overseas Territories and Crown Dependencies. * British national identity, the characteristics of British people and culture ...

botanist Botany, also called plant science, is the branch of natural science and biology studying plants, especially Plant anatomy, their anatomy, Plant taxonomy, taxonomy, and Plant ecology, ecology. A botanist or plant scientist is a scientist who s ...

and

ornithologist Ornithology, from Ancient Greek ὄρνις (''órnis''), meaning "bird", and -logy from λόγος (''lógos''), meaning "study", is a branch of zoology dedicated to the study of birds. Several aspects of ornithology differ from related discip ...

Allan Octavian Hume Allan Octavian Hume, Order of the Bath, CB Indian Civil Service, ICS (4 June 1829 – 31 July 1912) was a British political reformer, ornithologist, civil servant and botanist who worked in British Raj, British India and was the founding spirit ...

during his stay in

British India The provinces of India, earlier presidencies of British India and still earlier, presidency towns, were the administrative divisions of British governance in South Asia. Collectively, they have been called British India. In one form or another ...

as part of the

Imperial Civil Service The Indian Civil Service (ICS), officially known as the Imperial Civil Service, was the higher civil service of the British Empire in India during British rule in the period between 1858 and 1947. Its members ruled over more than 300 million p ...

. It was originally given the name black-shafted ternlet (''Sterna saundersi'') by Hume, which was later changed to its present common name. It is considered by some to be a subspecies of ''Sternula albifrons'', potentially of a larger species group, or otherwise conspecific.

Behavior

Feeding

The majority of the Saunders's tern's diet consists of various marine animals, including small fish,

crustaceans Crustaceans (from Latin meaning: "those with shells" or "crusted ones") are invertebrate animals that constitute one group of Arthropod, arthropods that are traditionally a part of the subphylum Crustacea (), a large, diverse group of mainly aquat ...

, and

mollusks Mollusca is a phylum of protostomic invertebrate animals, whose members are known as molluscs or mollusks (). Around 76,000 extant species of molluscs are recognized, making it the second-largest animal phylum after Arthropoda. The num ...

. It will also eat several varieties of insects. An individual will hover above the water for a sizable amount of time, before making a plunge dive to catch fish.

Status

It is a widely distributed species, and although population numbers are estimated to be small to large and even showing signs of decline, the species is not assessed as being close to the threshold of

vulnerability Vulnerability refers to "the quality or state of being exposed to the possibility of being attacked or harmed, either physically or emotionally." The understanding of social and environmental vulnerability, as a methodological approach, involves ...

, and its

conservation status The conservation status of a group of organisms (for instance, a species) indicates whether the group still exists and how likely the group is to become extinct in the near future. Many factors are taken into account when assessing conservation ...

has been assessed as "

least concern A least-concern species is a species that has been evaluated and categorized by the International Union for Conservation of Nature (IUCN) as not being a focus of wildlife conservation because the specific species is still plentiful in the wil ...

" on the

IUCN Red List The International Union for Conservation of Nature (IUCN) Red List of Threatened Species, also known as the IUCN Red List or Red Data Book, founded in 1964, is an inventory of the global conservation status and extinction risk of biological ...

References

Saunders's tern Saunders's tern (''Sternula saundersi''), sometimes known as the black-shafted tern, is a species of bird in the family Laridae. It is sparsely resident along the shores of the north-western Indian Ocean (namely southern Somalia, Arabian Peninsu ...

Birds of West Asia Birds of Pakistan Birds of Sri Lanka

Taxonomy articles created by Polbot {{charadriiformes-stub