Sandwich Tern Bird Facts (Thalasseus sandvicensis)

Visual Identification

Appearance

The Sandwich Tern is a medium-sized seabird with a sleek profile. Its plumage is primarily white, with pale grey upper wings and back. The bird sports a distinctive black crest and a long, slender black bill with a yellow tip. The legs are black.

During the breeding season, adults develop a full black cap extending to the nape in a spiky crest. Winter adults show a white forehead and crown.

Females and males are alike with no visual difference, although research shows that females have shorter heads and beaks, and males have longer lower legs and toes than females.

Juveniles have a barred pattern on their upper parts, darker bills and crowns that resemble non-breeding adults.

Size

Length

36cm to 41cm

Wingspan

85cm to 97cm

Weight

210g to 260g

Colours

Males and females have similar plumage

Primary Colour

White Grey

Secondary Colour

Black

Beak Colour

Black Yellow

Leg Colour

Black

Habitat and Distribution

Habitats

Woodland

The Sandwich Tern is not typically found in Woodland habitats.

Garden

The Sandwich Tern is not typically found in Garden habitats.

Wetland

The Sandwich Tern can be found in Wetland habitats.

Coastal

The Sandwich Tern can be found in Coastal habitats.

Urban

The Sandwich Tern is not typically found in Urban habitats.

Farmland

The Sandwich Tern is not typically found in Farmland habitats.

Grassland

The Sandwich Tern is not typically found in Grassland habitats.

Desert

The Sandwich Tern is not typically found in Desert habitats.

Tundra

The Sandwich Tern is not typically found in Tundra habitats.

Rainforest

The Sandwich Tern is not typically found in Rainforest habitats.

Mountain

The Sandwich Tern is not typically found in Mountain habitats.

Savanna

The Sandwich Tern is not typically found in Savanna habitats.

Distribution

Sandwich Terns inhabit coastal areas, preferring sandy or shingle beaches, estuaries, and offshore islands. They are found along the coasts of Europe, Africa, and the Americas, with significant populations in the North Sea and Baltic regions.

During winter, many European birds migrate to the west and south coasts of Africa. In North America, they breed along the Atlantic coast and winter in the Caribbean and South America.

UK colonies are important for the species' European population. They are scattered along the coastline of eastern and southern England, east and west Scotland, the Isle of Man, and parts of north Wales.

Elevation Range

Sea level to 100 meters

Climate zones

Temperate, Subtropical, Tropical

Distribution Map

This map gives you a rough idea of where you might spot a Sandwich Tern. The coloured areas show countries where these birds have been seen.

A few things to keep in mind:

Birds might not be everywhere in the coloured areas, for example, they may be present around the coast of that country
Where birds live can change with seasons and available food
This map is quite simple - it doesn't show exact locations

We're working on making our maps even better! Soon, we hope to show you:

More detailed maps for bigger countries, including state and region
How birds move around during different seasons

Resident

Breeding

Non-breeding

Vagrant

Distribution by Region

Species that can be found in the area throughout the year

Azerbaijan Bulgaria Denmark France Germany Greece Italy Latvia Macedonia Netherlands Poland Portugal Romania Spain Switzerland Turkey Ukraine

Species that are present in the area during their breeding season

Belgium Estonia Ireland Mexico Norway Russia Sweden The United Kingdom United States of America

Species that are present in the area outside their breeding season

Albania Croatia Cyprus Gibraltar Malta Slovenia

Species that appear infrequently (rare) and unpredictably outside their normal range

Bosnia and Herzegovina Czech Republic Faroe Islands Finland Hungary Iceland Montenegro Serbia Slovakia Svalbard and Jan Mayen Islands

Behaviour and Ecology

Bird Attributes

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Bird Attributes Explained

Our bird attributes system rates various aspects of a bird's capabilities on a scale of 0-100, based on data from field observations, scientific studies, and expert knowledge.

Attribute Categories:

Agility: Manoeuvrability, speed, and grace in flight or movement.
Strength: Physical power, often correlating with size and hunting abilities.
Adaptability: Ability to thrive in various environments or changing conditions.
Aggressiveness: Territorial behaviour and assertiveness, particularly during breeding seasons.
Endurance: Stamina, often seen in migration patterns or foraging behaviours.

Understanding the Ratings:

0-20: Very Low
21-40: Low
41-60: Average
61-80: High
81-100: Very High

Remember, these attributes are relative to other bird species and don't necessarily indicate superiority.

Hover over the icon next to each attribute for more information.

Tap the icon next to each attribute for more information.

Agility 85

Agility

Reflects the bird's manoeuvrability, speed, and grace in flight or movement.

The Sandwich Tern demonstrates remarkable agility in its aerial acrobatics and precise diving techniques. Their ability to plunge from heights of up to 12 metres, often hovering briefly before diving, showcases exceptional manoeuvrability and control.

Strength 60

Strength

Indicates the bird's physical power, often correlating with size and hunting abilities.

Whilst not particularly strong for their size, Sandwich Terns possess adequate strength to catch and carry fish. Their ability to dive into water and emerge with prey indicates a moderate level of muscular power.

Adaptability 75

Adaptability

Represents the bird's ability to thrive in various environments or changing conditions.

These birds show good adaptability, inhabiting various coastal environments across multiple continents and climate zones. Their ability to migrate long distances and adjust to different breeding and wintering grounds demonstrates considerable adaptiveness.

Aggressiveness 65

Aggressiveness

Measures the bird's territorial behaviour and assertiveness, particularly during breeding seasons.

Sandwich Terns display moderate aggressiveness, particularly during breeding season. They form dense colonies and will actively defend their nests against predators. However, they are not known for exceptional aggression compared to some other seabirds.

Endurance 80

Endurance

Reflects the bird's stamina, often seen in migration patterns or foraging behaviours.

With their long-distance migratory habits and ability to live for over 30 years in the wild, Sandwich Terns exhibit impressive endurance. Their capacity to undertake lengthy seasonal journeys and survive in diverse coastal environments indicates robust stamina and resilience.

Diet

Sandwich Terns primarily feed on small fish such as sand eels, sprats, and herring. They also consume small squid, crustaceans and occasionally insects.

These birds locate prey from the air, then dive rapidly to catch fish just below the water's surface, sometimes submerging completely.

Behaviour

Sandwich Terns are highly social, often seen in large, noisy colonies. They perform elaborate courtship rituals, including aerial displays and fish-offering.

These birds are skilled divers, plunging into the water from heights to catch fish, often hovering briefly before diving.

Vocalisation

The Sandwich Tern's call is a distinctive, harsh 'kirr-ik' or 'kerr-wick'. This loud, grating sound is often heard in flight or when the bird is alarmed. During courtship, males produce a softer, purring 'krurr-rr-rr' sound, accompanied by head-bobbing displays.

A cackling ‘gagaga’ cry is commonly heard from birds on the nest when intruders approach and may also be heard when they are defending foraging grounds.

Nesting & Breeding

Sandwich Terns breed in dense colonies, often alongside other tern species or gulls, between 100 and 4,000 pairs. Pair formation begins in April, with elaborate courtship displays, including aerial acrobatics and fish-presenting.

Nests are simple scrapes in sand or shingle, sometimes lined with vegetation. Females typically lay 1-2 eggs, which are variable in colour and can be pure white to buff-coloured with dark brown spots. Both parents share incubation duties.

Nests are at risk of being washed away by the tide, and in order to add an extra layer of protection, they often defecate around the rim of their nest scrape, with their droppings solidifying into a protective ‘ring’ which then has a greater chance of withstanding heavy rain or flooding.

Eggs hatch after about 21-29 days, and chicks fledge at 28-30 days. Parents continue to feed fledglings for several weeks after they leave the nest.

Conservation and Status

Global Conservation Status

Least Concern ^[1]

While currently listed as Least Concern globally, Sandwich Terns face threats from habitat loss, disturbance at breeding sites, and climate change impacts on fish populations.

Conservation efforts focus on protecting nesting colonies and managing coastal habitats to ensure suitable breeding grounds.

Population Data

Global Population Estimate

490,000 - 640,000 individuals ^[2]

Global Population Trend

^[3]

Trend data may be uncertain or fluctuating

Birdwatching Tips

Look for Sandwich Terns along coastal areas, especially near sandy or shingle beaches.
Listen for their distinctive 'kirr-ik' call, which is louder and harsher than other tern species.
Observe their unique diving technique, where they plunge straight down with half-closed wings.
In the UK, visit coastal reserves like Blakeney Point in Norfolk during the summer months.

Additional Information

Quick Facts

Other names:

Cabot's Tern

Family:

Laridae

Average Lifespan

12 years

Max Lifespan

30.8 years ^[4]

Predators

Main predators include large gulls, skuas, foxes, and rats, which often target eggs and chicks in breeding colonies.

Did You Know?

Sandwich Terns can live for over 30 years in the wild.
They were named after Sandwich, Kent, where they were first scientifically described, not after the food item.
These birds can dive from heights of up to 12 meters to catch fish.
The United States is home to an estimated 25 to 32 percent of the global population of Sandwich terns, with up to 46,945 breeding pairs.

References

1
website: BirdLife International. 2021. Thalasseus sandvicensis (Europe assessment). The IUCN Red List of Threatened Species 2021: e.T22694591A166282359.
View source
2 3
report, 2015: Wetlands International
4
journalArticle, 2000: Monaghan and Metcalfe, Genome size and longevity, Trends Genet, 16:331-332
View source