Black Tern

Chlidonias niger

Introduction

This delicate marsh tern once nested in Britain in large colonies, but these disappeared as wetland areas were drained; it is now an annual visitor from Europe.

Key Stats

Scarce

72.5g

3-3

<1%

BTO Records

44k records

Population and distribution stats for:

No data

No current data

-100% contraction

No data

No current data

% expansion

Identification

Curated resources to aid in the identification of Black Tern

Songs and Calls

Open Close

Listen to example recordings of the main vocalisations of Black Tern, provided by xeno-canto contributors.

Call:

Status and Trends

Population size, trends and patterns of distribution based on BTO and partnership surveys and atlasses with data collected by BTO volunteers.

Conservation Status

Open Close

This species can be found on the following statutory and conservation listings and schedules.

UK Birds of Conservation Concern

Green listed

Species of European Conservation Concern

Least Concern

IUCN Red List of Threatened Species (global)

Least Concern

Schedule 1 Licence required (to disturb)*

Yes

Birds Directive Annex 1

Yes

Listed on the Annexes of*

WCA(I), WBD(I), Bern(III), Bonn(II*), AEWA

* A guide only. Check details with the original legislation, especially those marked with an asterisk. See About Birdfacts for more information.

Population Size

Open Close

BOU Category

Source

First Record*

1544

* First documented occurrence. Most species undoubtedly occurred before this. See About Birdfacts for more information.

Population Change

Open Close

Black Tern was an abundant breeding bird in East Anglia and elsewhere in southern and eastern England until the middle of the 19th century [Parkin & Knox 2010]. The last confirmed breeding record was from Nottingham in 1978 and the species is now classed as a former breeder [Stanbury et al. 2024]. Black Tern occurs regularly across the UK as a passage migrant, particularly in the spring; influxes can occur when easterly winds force birds further west on their return to continental breeding grounds [Balmer et al. 2013]. During autumn migration, sightings tend to be more coastal and more likely from the south and east [Parkin & Knox 2010]. The surinamensis race, which breeds in Canada and the northern USA and winters in South America, is a very rare visitor to the UK; one female has been recorded in an Arctic Tern colony in Northumberland since 2020 – it bred with an Arctic Tern in 2024 [Bacon et al. 2024].

Distribution

Open Close

Black Terns are regular migrants and large spring influxes can occur if birds heading to continental breeding grounds are forced west by easterly winds. Passage birds were widely recorded during the 2007–11 breeding atlas. Black Terns last bred in Britain in 1978 and in Ireland in 1975.

Occupied 10-km squares in UK

These figures come from Bird Atlas 2007 and indicate how widespread a species is.

No. occupied in winter

% occupied in winter

0.1%

Bird Atlas distribution maps show where bird species breed or winter in Britain and Ireland. For breeding maps, larger dots indicate higher certainty the species bred in that area.

Click the map to enlarge,
or view it on Bird Atlas Mapstore.

Click the map to enlarge,
or view it on Bird Atlas Mapstore.

To view and download up-to-date distribution information aggregated from across BTO and partnership surveys and schemes, see our data holdings on the NBN Atlas.

European Distribution Map

European Breeding Bird Atlas 2

Distribution Change

Open Close

Change in occupied 10-km squares in the UK

These figures come from Bird Atlas 2007-11 and indicate by how much occupied areas have expanded or contracted over recent decades.

% change in range in breeding season (1968–72 to 2008–11)

-100 %

Bird Atlas distribution change maps show how bird distributions have changed through time. Coloured upward-pointing triangles show places apparently colonised over the period; grey downward-pointing triangles show places apparently vacated. Shading show places occupied.

Winter Distribution change for Black Tern

Click the map to enlarge,
or view it on Bird Atlas Mapstore.

Breeding Distribution change for Black Tern

Click the map to enlarge,
or view it on Bird Atlas Mapstore.

Seasonality

Open Close

Black Tern is a regular passage migrant in late spring and autumn.

Weekly pattern of occurrence

The graph shows when the species is present in the UK, with taller bars indicating a higher likelihood of encountering the species in appropriate regions and habitats.

Phenology graph — Weekly occurrence patterns (shaded cells and reporting rates (vertical bars) based on BirdTrack data. Reporting rates give the likelihood of encountering the species each week.

Movement

Information about Black Tern movements and migration based on online bird portals (e.g. BirdTrack), Ringing schemes and tracking studies.

Britain & Ireland movement

Open Close

View a summary of recoveries in the Online Ringing Report

European movements

Open Close

EuroBirdPortal uses birdwatcher's records, such as those logged in BirdTrack to map the flows of birds as they arrive and depart Europe. See maps for this species here.

The Eurasian-African Migration Atlas shows movements of individual birds ringed or recovered in Europe. See maps for this species here.

Biology

Lifecycle and body size information for Black Tern, including statistics on nesting, eggs and lifespan based on BTO ringing and nest recording data.

Productivity and Nesting

Open Close

Nesting timing

Typical (exceptional) number of broods

Source

Egg measurements

Typical length x width

35x25 mm

Mass (% shell)

11.4g (5%)

Source

Clutch Size

Typical number

3-3 eggs

Observed minimum and maximum

1-4 eggs

Source

Incubation

Incubation by

Female (occ. Male)

Typical duration

22-21 days

Source

Fledging

Type of chick

Semi-precocial, downy

Typical duration

25-19 days

Source

Survival and Longevity

Open Close

Survival is shown as the proportion of birds surviving from one year to the next and is derived from bird ringing data. It can also be used to estimate how long birds typically live.

Biometrics

Open Close

Wing length and body weights are from live birds (source).

Ring Size

B+

Classification, names and codes

Taxonomy, names and species codes for Black Tern

Classification and Codes

Open Close

Order: Charadriiformes
Family: Laridae
Scientific name: Chlidonias niger
Authority: Linnaeus, 1758

BTO 2-letter code: BJ
BTO 5-letter code: BLATE
Euring code number: 6270

Alternate species names

Open Close

Catalan: fumarell negre
Czech: rybák cerný
Danish: Sortterne
Dutch: Zwarte Stern
Estonian: mustviires
Finnish: mustatiira
French: Guifette noire
Gaelic: Steàrnag-dhubh

German: Trauerseeschwalbe
Hungarian: kormos szerko
Icelandic: Kolþerna
Irish: Geabhróg Dhubh
Italian: Mignattino comune
Latvian: melnais zirinš
Lithuanian: juodoji žuvedra
Norwegian: Svartterne

Polish: rybitwa czarna
Portuguese: trinta-réis-negro / gaivina-preta
Slovak: corík cierny
Slovenian: crna cigra
Spanish: Fumarel común
Swedish: svarttärna
Welsh: Corswennol Ddu

English folkname(s): Carr Swallow, Blue Darr

More Evidence

More evidence from Conservation Evidence.com

Partners

Birdfacts is based on data collected by volunteers participating in surveys that are organised and funded by BTO, RSPB, Esmée Fairbairn Foundation, JNCC and other partners.

BTO

Esmée Fairbairn Foundation

JNCC

RSPB

Find a Species

Search by common or scientific name

Or view the alphabetical list of UK bird species