Royal Tern (Thalasseus maximus)

OTHER NAMES: N/A
Latin Etymology: Thalasseus ("fisherman") maximus ("greatest")

Two non-breeding Royal Tern (Thalasseus maximus) at Tarcoles, Costa Rica - November 2025

Featured Subspecies: N/A
Weight: 350-500g  /  Length: 45-50cm  /  Wingspan: 130cm
NO UK STATUS/ IUCN Red List: Least Concern

The joint second largest of all terns, second only to the Caspian, the Royal Tern is a large sturdy bird with a distinct orange beak that would differentiate it from other large terns within it's range. They are an exclusively coastal species, found around the Carribean and Baja Califoria, as well as the South East of South America year round, as well as Central America in the Winter.

Related Species:
Order: Charadriiformes

Family: Laridae (Formerly Sternidae)

Genus: Thalasseus

SUBSPECIES: none - monotypic 

 - Sighting Locations -

COSTA RICA - Spanish - Charrán Real
Wintering migrant
 - COSTA RICA 2025 TRIP: Seen at Tarcoles

Further Notes: BirdForum Opus, IUCN Red List, RSPB, Wikipedia, Xeno-canto

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Elegant Tern (Thalasseus elegans)

OTHER NAMES: N/A
Latin Etymology: Thalasseus elegans

Non-breeding Elegant Tern (Thalasseus elegans) at Monterey, California - September 2022

Featured Subspecies: N/A
Weight: 200-300g  /  Length: 39-43cm  /  Wingspan: 76-81cm
NO UK STATUS / IUCN Red List: Near Threatened

A somewhat paradoxical species - they have incredibly dense breeding colonies but only in a few very specific locations around the Gulf of California, but meanwhile its non-breeding range stretches from central Chile up along the Pacific Coast to the Oregon. They also, from a birding perspective are unusually variable in their non-breeding plumage, with their bills in particular ranging across red, orange, yellow and pink, making it a somewhat frustrating exercise to pick out other species in amongst them.

Related Species:

Order: Charadriiformes

Family: Laridae (Formerly Sternidae)

Genus: Thalasseus

SUBSPECIES: none - monotypic 

 - Sighting Locations -

UNITED STATES 
Breeds at a single site in California, nn-breeding along Souther Half of West Coast
 - CALIFORNIA 2022 TRIP: Seen at Hayward and Monterey 

Further Notes: BirdForum Opus, IUCN Red List, RSPB, Wikipedia, Xeno-canto

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Caspian Tern (Hydroprogne caspia)

OTHER NAMES: N/A
Latin Etymology: Hydroprogne ("water swallow") caspia ("of the Caspian sea")

Adult Caspian Tern (Hydroprogne caspia) at Fort Peck, Montana, USA - August 2022

Featured Subspecies: N/A
Weight: 530-782g  /  Length: 48-60cm  /  Wingspan: 127-145cm
NO UK STATUS/ IUCN Red List: Least Concern

The largest of all terns by a margin of up to 50%, and, despite the very localised suggesting name, one of the most globally distributed, found on every continent except South America and Antarctica, albeit with a very perculiar mix of migratory and resident populations that border on each other in perculiar ways. It can be found on both fresh and saltwater.

Related Species:
Order: Charadriiformes

Family: Laridae (Formerly Sternidae)

Genus: Hydroprogne

SUBSPECIES: none - monotypic 

 - Sighting Locations -

UNITED STATES 
DA patchy, migrant distribution primarily along the coast and Great Lakes
 - CALIFORNIA 2022 TRIP: Seen at Berkeley

 - CHICAGO TO ALASKA ROADTRIP 2024: Seen in Montana

Further Notes: BirdForum Opus, IUCN Red List, RSPB, Wikipedia, Xeno-canto

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Roseate Tern (Sterna dougallii)

OTHER NAMES: N/A
Latin Etymology: Sterna (Old English word for Black Tern) dougallii (after Dr Peter McDougall)

Adult Roseate Tern (subspecies S. d. dougallii) at Coquet Island, Northumbria- Month 2022

Featured Subspecies: Sterna dougallii dougallii
Weight: g/kg  /  Length: 33-36cm  /  Wingspan: 67-76cm
UK RED LIST / IUCN Red List: Least Concern 

On Coquet Island in Northumbria lies the most Northerly regular breeding colony of roseate terns in the world. Formerly more common in the UK, they are now subject to a single no-access allowed location where special nesting box have been provided to support them breed. Yet, elsewhere in the world they are more numerous, and found more substantially around East and South East Asia, Australia, Madagascar and the Caribbean, with various other smaller colonies. Like all terns found in the UK, they are Summer migrants, and so can, on occassion, be seen on passage elsewhere in England.

Related Species:
Order: Charadriiformes
Family: Sternidae
Genus: Sterna
SUBSPECIES: S. d. dougallii, S. d. arideensis, S. d. korustes, S. d. bangsi, S. d. gracilis

 - Sighting Locations -

UNITED KINGDOM - An extremely rare and local Summer visitor and breeding species, almost exclusively on Coquet Island

 - Seen at Coquet Island (June 2022)

Further Notes: BirdForum Opus, IUCN Red List, RSPB, Wikipedia, Xeno-canto .

White-Winged Black Tern (Chlidonias leucopterus)

OTHER NAMES: White-Winged Tern
Latin Etymology: Chlidonias ("swallow-like") leptopterus ("slender wing")

Summer Adult White-Winged Black Tern (Chlidonias leucopterus) at Eyebrooke Reservoir, Rutland - May 2018

Featured Subspecies: N/A
Weight: 42-79g  /  Length: 23-27cm  /  Wingspan: 58-67cm
NO UK STATUS / IUCN Red List: Least Concern

The White-Winged Black Tern is certainly one of those species which has a obliquely descriptive name; it indeed resembles pretty much a Black Tern except with white wings.  Unlike it's near namesake, it isn't a regular passage species to the UK instead only turning up as a vagrant as it migrates between Africa and Eastern Europe.

Related Species:
Order: Charadriiformes
Family: Sternidae
Genus: Chlidonias
SUBSPECIES: none - monotypic 

 - Sighting Locations -

UNITED KINGDOM - A rare vagrant

 - A single bird seen at  Eyebrooke Reservoir in May 2018.

Further Notes: BirdForum Opus, IUCN Red List, RSPB, Wikipedia, Xeno-canto

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Whiskered Tern (Chlidonias hybrida)

OTHER NAMES: N/A

Latin Etymology: Chlidonias ("swallow-like") hybrida ("hybrid")

                                             Whiskered Tern (subspecies C. h. hybrida) at Laguna Navaseca, Spain - April 2016

Featured Subspecies: Chlidonias hybrida hybria

Weight: 80-100g  /  Length: 23-25cm  /  Wingspan: 74-78cm

NO UK STATUS / IUCN Red List: Least Concern

The palest of the three "Marsh Terns" found regularly in Europe, the Whiskered Tern more resembles a "classical" tern with a dark underbelly than the other two when in full breeding plumage. This is in fact reflected in the latin name "hybrida" - which suggests it does look like a hybrid of Marsh and "Sterna" terns.  A rare visitor to the UK, and I once attempted to see a juvenile that was present at Rutland Water, but was unable to positively pick it out without the more distinctive plumage at the great distances.  In Laguna Navaseca in Toledo province they were a common and easy to see presence, fishing in front of hides in the same way Common Terns do in wetlands in the UK.

Related Species:
Order: Charadriiformes
Family: Sternidae
Genus: Chlidonias
Subspecies: C. h. hybrida, C. h. delalandii, C. h. javanicus

 - Sighting Locations -

CAMBODIA - Khmer Name: រំពេរពោះប្រផេះ ("? Grey Belly")

A locally common Winter visitor and passage migrant.

 - CAMBODIA/SINGAPORE 2019 TRIP: Common approaching Prek Toal

SPAIN - Spanish - Fumarel cariblanco ("White-cheeked tern")

Locally common Summer migrant

 - MADRID 2016 TRIP: Abundant at Laguna Navaseca (dozens seen) and one flock seen at Laguna del Longar distantly.

Further Notes: BirdForum Opus, IUCN Red List, RSPB, Wikipedia, Xeno-canto .

Gull-billed Tern (Gelochelidon nilotica)

OTHER NAMES: N/A

Latin Etymology: Gelochelidon ("laughing swallow") nilotica ("of the Nile")

Five adult Gull-billed Tern (subspecies G. n. niloctica) at Laguna del Longar, Spain - April 2016

Featured Subspecies: Grelochelidon nilotica nilotica

Weight: 150-292g  /  Length: 33-42cm  /  Wingspan: 76-91cm

NO UK STATUS / IUCN Red List: Least Concern

The Gull-billed Tern is a comparatively powerfully built tern found sporadically across all continents except Antarctica is variable densities.  Through much of it's range, it is a coastal species, though it may breed at more inland sites. The colony I encountered was at Laguna del Longar in Toledo province, where they breed on the sandbars, although these birds were washing themselves in the fresher inlet streams closer to the hides.

Related Species:
Order: Charadriiformes
Family: Sternidae
Genus: Gelochelidon
Subspecies: G. n. niloctica, G. n. affinis, G. n. macrotarsa, G. n. aranea, G. n. vanrossemi, G. n. gronvoldi

 - Sighting Locations -

SPAIN - Spanish - Pagaza piconegra ("Black-beaked Tern")

Local Summer Migrant

 - MADRID 2016 TRIP: Abundant at Laguna del Longar (at least fifteen seen around Lagoon at various times)

Further Notes: BirdForum Opus, IUCN Red List, RSPB, Wikipedia, Xeno-canto .

Little Tern (Sternula albifrons)

OTHER NAMES: N/A

Latin Etymology: Sternula ("diminutive of Sterna - black tern) albifrons ("white forehead")

Adult Little Tern (subspecies S. a. albifrons) at Rye Harbour, Kent - May 2012

Featured Subspecies: Sterna albifrons albifrons
Weight: 50g  /  Length: 20-28cm  /  Wingspan: 45-55cm
UK AMBER LIST / IUCN Red List: Least Concern

The Little Tern is the smallest and one of the rarest species of Tern in the UK - it requires undisturbed shingle on while to nest which is difficult to find in this modern age - with dog walkers and the like disturbing them preventing them from nesting, and as a species which is a notoriously poor breeder this is a bit of a problem.  They are much smaller than other terns found in the UK, and the telltale sign is their yellow beak with a black tip which gives them away.   A charming little bird, the best places to see them are protected sites where fences keep them safe from predators and humans.

Related Species:
Order: Charadriiformes
Family: Sternidae
Genus: Sternula
Subspecies: S. a. albifrons, S. a. guineae, S. a. sinensis

- Sighting Locations -

UNITED KINGDOM - Rare and very local breeding Summer migrant (1,900 pairs)

 - Birds seen at publicized colony at Rye Harbour in May 2015

ITALY - Italian - Fraticello

A rare breeder

 - SICILY 2018 TRIP - Seen from Syracuse 

Further Notes: BirdForum Opus, IUCN Red-List, RSPB, Wikipedia, Xeno-canto .

Black Tern (Chlidonias Niger)

OTHER NAMES: Short-tailed tern, Semipalmated tern, Sea pigeon
Latin Etymology: Chlidonias ("swallow-like") niger ("black")

Juvenile Black Tern (subspecies C. n. niger) at Rutland Water, Rutland - September 2010

Featured Subspecies: Chlidonias niger niger
Weight: 50-60g  /  Length: 23-28cm  /  Wingspan: 61cm

UK AMBER LIST / IUCN Red List: Least Concern

Black Terns are passage migrants that can be seen over reservoirs and lakes during migration times. Seeing them is about being in the right place at the right time and photographing them will depend on convenience of distance.  The bird here is a juvenile, it is the adults in breeding plumage who are entirely sooty black as the name suggests.  They are the only species of the "Marsh Terns" who are consistently seen in the UK.  Generally my experience of Black Terns is that though at the right time of the year they aren't that difficult to see, they tend to remain fairly distant to hides for the sake of getting good views.

Related Species:

Order: Charadriiformes
Family: Sternidae
Genus: Chlidonias
Subspecies: C. n. niger, C. n. surinamensis

- Sighting Locations -

UNITED KINGDOM - Scarce passage migrant (in the hundreds)

 - Seen on passage at Rutland Water and Summerleys

Further Notes: BirdForum Opus, IUCN Red List, RSPB, Wikipedia, Xeno-canto 

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Common Tern (Sterna hirundo)

OTHER NAMES: Sea Swallow

Latin Etymology: Sterna (Old English word for Black Tern) hirundo ("swallow")

Adult Common Tern (subspecies S. h. hirundo) at London Wetland Centre, London - June 2018

Featured Subspecies: Sterna hirundo hirundo

Weight: 110-141g  /  Length: 12-14cm  /  Wingspan: 77-98cm

UK AMBER LIST / IUCN Red List: Least Concern

By far the easiest Tern species to see, if not actually the most numerous - common terns breed at many locations inland, particularly at nature reserves where islands have been made specifically for them to nest. They can also often be seen over more or less any decent sized body of water with some luck. Visually very similar to the Arctic Tern, there are subtle differences, but you can almost guarantee that a tern of this sort seen inland is a common tern.


Related Species:
Order: Charadriiformes
Family: Sternidae (Terns)
Genus: Sterna
Subspecies: S. h. hirundo, S. h. minussensis, S. h. tibetana, S. h. longipennis 

- Sighting Locations -

UNITED KINGDOM - Locally fairly common Summer migrant breeding species (12000 pairs)

 - Seen at various sites including Farne Islands,  Rutland Water, Trevose Head, Rainham Marshes and Pitsford Reservoir

Further Notes: BirdForum Opus, IUCN Red List, RSPB, Wikipedia, Xeno-canto
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Sandwich Tern (Thalasseus sandvicensis)

OTHER NAMES: Boatswain, Surf Tern
Latin Etymology: Thalasseus ("fisherman") sandvicensis (named for Sandwich, Kent)

Assorted age and gender Sandwich Terns (subspecies T. s. sandvicensis) at Farne Islands, Northumbria - July 2009

Featured Subspecies: Thalasseus sandvicensis sandvicensis OR monotypic
Weight: 180-300g  /  Length: 34-45cm  /  Wingspan: 100cm

UK AMBER LIST / IUCN Red List: Least Concern

The Sandwich Tern is an exclusively coastal tern which breeds primarily along the East and South Coasts during the Summer although it may be seen on passage elsewhere. It is technically our second most common tern after the Arctic, but, both of the above I would consider harder to see on the basis that they are purely coastal dwelling rather than the common tern which breeds inland. Terns are easiest to photograph when on the ground and I would recommend going to the Farne Islands in the breeding season for this species.

Related Species:

Order: Charadriiformes

Family: Laridae (Formerly Sternidae)

Genus: Thalasseus
Subspecies: Either T. s. sandvicensis, T. s. acuflavidus, T. s. eurygnathus or monotypic*

- Sighting Locations -

UNITED KINGDOM - Local Summer breeding migrant (12,000 pairs)

 - Birds seen commonly at a large number of sites, including but not limited to Trevose Head, Rye Harbour, Oare Marshes and Farne Islands

Further Notes: BirdForum Opus, IUCN Red List, RSPB, Wikipedia, Xeno-canto 

*The American subspecies acuflavidus and eurygnathus are split as Cabot's Tern and Cayenne Tern, either as one or two species, which I will treat as separate should I see them, but I mention them here for clarity. 

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Arctic Tern (Sterna paradisaea)

OTHER NAMES: Sea Swallow, Sparling, Pickieterno, Rittock
Latin Etymology: Sterna (Old English word for Black Tern) paradisaea ("paradise")

Adult Arctic Tern (Sterna paradisaea) at Farne Islands, Northumbria - July 2009

Featured Subspecies: N/A
Weight: 86-127g  /  Length: 33-36cm  /  Wingspan: 76-85cm

UK AMBER LIST / IUCN Red List: Least Concern

Most famous for its pole to pole migration, the arctic tern is infact hard to differentiate from the common tern, which is, as the name suggests, more common. Generally, the arctic tern is more of a coastal bird than the common tern (although common are found at the coast, and arctic occasionally inland on passage). Though they are very similar to common terns, features such as the lack of black on the beak, a grey tinged underside and tail-streamers which extend well beyond the tips of the wings when on the ground. The Farne islands in the spring are a superb place to see this bird up close - although watch out for being dive bombed as they protect their nests!


Related Species:
Order: Charadriiformes
Family: Sternidae
Genus: Sterna 
Subspecies - none - monotypic

- Sighting Locations -

UNITED KINGDOM - Local Summer breeding migrant (53,000 pairs)

 - Common breeder on the Farne Islands

Further Notes: BirdForum Opus, IUCN Red List, RSPB, Wikipedia, Xeno-canto .