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 Aves (), characterised by feathers, toothless beaked jaws, the laying of hard-shelled eggs, a high metabolic rate, a four-chambered heart, and a strong yet lightweig ...

in the family

Laridae Laridae is a family of seabirds in the order Charadriiformes that includes the gulls, terns, skimmers and kittiwakes. It includes around 100 species arranged into 22 genera. They are an adaptable group of mostly aerial birds found worldwide. Ta ...

. 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 ~19.8% of the water on Earth's surface. It is bounded by Asia to the north, Africa to the west and Australia to the east. To the south it is bounded by ...

(namely southern

Somalia Somalia, , Osmanya script: 𐒈𐒝𐒑𐒛𐒐𐒘𐒕𐒖; ar, الصومال, aṣ-Ṣūmāl officially the Federal Republic of SomaliaThe ''Federal Republic of Somalia'' is the country's name per Article 1 of thProvisional Constitut ...

, Arabian peninsula,

Socotra Socotra or Soqotra (; ar, سُقُطْرَىٰ ; so, Suqadara) is an island of the Republic of Yemen in the Indian Ocean, under the ''de facto'' control of the UAE-backed Southern Transitional Council, a secessionist participant in Yemen� ...

Pakistan Pakistan ( ur, ), officially the Islamic Republic of Pakistan ( ur, , label=none), is a country in South Asia. It is the world's List of countries and dependencies by population, fifth-most populous country, with a population of almost 24 ...

Andaman and Nicobar Islands The Andaman and Nicobar Islands is a union territory of India consisting of 572 islands, of which 37 are inhabited, at the junction of the Bay of Bengal and the Andaman Sea. The territory is about north of Aceh in Indonesia and separated ...

and northern

Sri Lanka Sri Lanka (, ; si, ශ්‍රී ලංකා, Śrī Laṅkā, translit-std=ISO (); ta, இலங்கை, Ilaṅkai, translit-std=ISO ()), formerly known as Ceylon and officially the Democratic Socialist Republic of Sri Lanka, is an ...

). It is a close relative of the

Little Tern The little tern (''Sternula albifrons'') is a seabird of the family Laridae. It was formerly placed into the genus ''Sterna'', which now is restricted to the large white terns. The genus name is a diminutive of '' Sterna'', "tern". The specific ...

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. Ot ...

Yellow-billed tern The yellow-billed tern (''Sternula superciliaris'') is a small seabird found in South America. It is a species of tern in the family Laridae. It is found in Argentina, Bolivia, Brazil, Colombia, Ecuador, French Guiana, Guyana, Panama, Paraguay ...

, and

Peruvian tern The Peruvian tern (''Sternula lorata'') is a species of tern in the family Laridae. Found in northern Chile, Ecuador, and Peru, its natural habitats are hot deserts, sandy shores, and coastal saline lagoons. It is threatened by habitat loss. In ...

. 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 organ ...

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 ( "feather") 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, ...

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

primaries Primary elections, or direct primary are a voting process by which voters can indicate their preference for their party's candidate, or a candidate in general, in an upcoming general election, local election, or by-election. Depending on the c ...

, 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 other wingtip. For example, the Boeing 777–200 has a wingspan of , and a wandering albatross (''Diomedea exulans'') caught in 1965 had a wingspan ...

of 50-55 cm(20-21 in). It has an average wing length of 16.6 cm(6.5 in), an average

bill Bill(s) may refer to: Common meanings * Banknote, paper cash (especially in the United States) * Bill (law), a proposed law put before a legislature * Invoice, commercial document issued by a seller to a buyer * Bill, a bird or animal's beak Plac ...

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. ** Britishness, the British identity and common culture * British English ...

botanist and

ornithologist Ornithology is a branch of zoology that concerns the "methodological study and consequent knowledge of birds with all that relates to them." Several aspects of ornithology differ from related disciplines, due partly to the high visibility and th ...

Allan Octavian Hume Allan Octavian Hume, CB ICS (4 June 1829 – 31 July 1912) was a British civil servant, political reformer, ornithologist and botanist who worked in British India. He was the founder of the Indian National Congress. A notable ornithologist, Hu ...

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 on the Indian subcontinent. Collectively, they have been called British India. In one ...

as part of the Imperial Civil Service. 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 (Crustacea, ) form a large, diverse arthropod taxon which includes such animals as decapods, seed shrimp, branchiopods, fish lice, krill, remipedes, isopods, barnacles, copepods, amphipods and mantis shrimp. The crustacean gr ...

, and

mollusks Mollusca is the second-largest phylum of invertebrate animals after the Arthropoda, the members of which are known as molluscs or mollusks (). Around 85,000 extant species of molluscs are recognized. The number of fossil species is esti ...

. 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.

References

Saunders's tern Birds of Western Asia Birds of Pakistan Birds of Sri Lanka Saunders's tern Taxonomy articles created by Polbot {{charadriiformes-stub