Black Guillemot

Cepphus grylle

Introduction

Found around the rocky coasts of Ireland and north-west Britain, this distinctive little seabird has a sharp black bill and scarlet feet.

In summer the Black Guillemot is all black, save for prominent white wing patches. In winter the plumage becomes almost white below with upperparts barred black-and-white. It is one of our smaller auks, only slightly larger than a Puffin and it has a thin whistling call.

The Black Guillemot is one of our most sedentary seabirds, only moving a short distance offshore in winter. The provision of nest boxes sited within harbour walls has helped this species.

Key Stats

Scarce

409.3g

1-2

BTO Records

48k records

Publications

Population and distribution stats for:

No data

20k pairs

-5.5% contraction

No data

No current data

2.7% expansion

Identification

Curated resources to aid in the identification of Black Guillemot

ID Videos

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This section features BTO training videos headlining this species, or featuring it as a potential confusion species.

Winter Auks

Songs and Calls

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

Call:

Other:

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

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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)*

Birds Directive Annex 1

Listed on the Annexes of*

Bern(III)

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

Population Size

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UK (breeding)

20 thousand pairs (1998-03)

Source

BOU Category

Source

First Record*

1661

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

Population Change

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Black Guillemots nest within rock crevices rather than in the open amongst other seabirds within cliff nesting colonies, and hence they are difficult to survey and counts were incomplete during the initial Seabird Census in 1969–70. The population remained broadly stable between the 1985–88 Census and Seabird 2000 (1998–2002) and annual data from the Seabird Monitoring Programme suggest it has been stable subsequently. Results from the recent Seabirds Count (2015–2021) are expected to offer a more comprehensive assessment of the recent trends (JNCC 2022).

Distribution

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Black Guillemots are highly sedentary and their principal range in both seasons is the coasts of Ireland, Anglesey, the Isle of Man and northern and western Scotland. In winter there are additional scattered records along the coasts of the North Sea and southwest and southern England, perhaps reflecting limited dispersal away from breeding areas.

Occupied 10-km squares in UK

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

No. occupied in breeding season

395

% occupied in breeding season

13%

No. occupied in winter

403

% occupied in winter

13%

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.

Winter distribution <br/> 2007/08–10/11 — Winter distribution
2007/08–10/11

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

Breeding distribution <br/> 2008–11 — Breeding distribution
2008–11

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

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Breeding range change is most noticeable in the west of Scotland when compared with both of the previous atlases, with losses predominating in the Outer and Inner Hebrides, but striking gains are shown in the inner north Clyde area and on the east side of the Kintyre Peninsula.

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)

-5.5%

% change in range in winter (1981–84 to 2007–11)

2.7%

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

Winter distribution change <br/> from 1981–84 to 2007–11 — Winter distribution change
from 1981–84 to 2007–11

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

Breeding distribution change <br/> from 1968–72 to 2008–11 — Breeding distribution change
from 1968–72 to 2008–11

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

Seasonality

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Black Guillemots are recorded throughout the year, though more consistently during summer at suitable coastal breeding sites.

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 Guillemot movements and migration based on online bird portals (e.g. BirdTrack), Ringing schemes and tracking studies.

Britain & Ireland movement

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View a summary of recoveries in the Online Ringing Report

Foreign locations of birds ringed or recovered in Britain & Ireland

Dots show the foreign destinations of birds ringed in Britain & Ireland, and the origins of birds ringed overseas that were subsequently recaptured, resighted or found dead in Britain & Ireland. Dot colours indicate the time of year that the species was present at the location.

Winter (Nov-Feb)
Spring (Mar-Apr)
Summer (May-Jul)
Autumn (Aug-Oct)

Foreign locations of birds ringed or recovered in Britain & Ireland

European movements

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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 Guillemot, including statistics on nesting, eggs and lifespan based on BTO ringing and nest recording data.

Productivity and Nesting

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.

View number ringed each year in the Online Ringing Report.

Lifespan

Typical life expectancy of bird reaching breeding age

11 years with breeding typically at 4 years

Source

Maximum age from a ringed bird

24 years, 8 months, 19 days (set in 2019)

Source

Survival of adults

All adults

0.87±0.007

Source

Biometrics

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

Wing length

Average ±1 std deviation; range and sample size in brackets.

All adults

164.6±4.7 mm

(157-174 mm, N=43)

Body weight

Average ±1 std deviation; 5th and 95th percentiles and sample size in brackets.

All adults

409.3±36.3 g

(360-480 g, N=35)

Ring Size

Classification, names and codes

Taxonomy, names and species codes for Black Guillemot

Classification and Codes

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Order: Charadriiformes
Family: Alcidae
Scientific name: Cepphus grylle
Authority: Linnaeus, 1758

BTO 2-letter code: TY
BTO 5-letter code: BLAGU
Euring code number: 6380

Alternate species names

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Catalan: somorgollaire alablanc
Czech: alkoun obecný
Danish: Tejst
Dutch: Zwarte Zeekoet
Estonian: krüüsel
Finnish: riskilä
French: Guillemot à miroir
Gaelic: Gearra-glas

German: Gryllteiste
Hungarian: fekete lumma
Icelandic: Teista
Irish: Foracha Dhubh
Italian: Uria nera
Latvian: melnais alks
Lithuanian: paprastoji taiste
Norwegian: Teist

Polish: nurnik (zwyczajny)
Portuguese: airo-d'asa-branca
Slovak: svištún zrkadlový
Slovenian: crna njorka
Spanish: Arao aliblanco
Swedish: tobisgrissla
Welsh: Gwylog Ddu

Research

Interpretation and scientific publications about Black Guillemot from BTO scientists.

Causes of Change and Solutions

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Causes of change

Unlike other auks, Black Guillemots tend to remain close to their breeding colonies when foraging and the stable trend suggests that conditions have remained reasonably favourable over the last 30 or 40 years. However, knowledge of the breeding ecology is limited in comparison to many other seabird species and therefore further knowledge of this species would be valuable in order to understand possible threats.

Publications (5)

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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

Citing BirdFacts

If you wish to cite particular content in this page (e.g. a specific value) it is best to use the original sources as linked in the page. For a more general citation of the whole page please use: BTO (20XX) BirdFacts Species: profiles of birds occurring in the United Kingdom. BTO, Thetford (www.bto.org/birdfacts, accessed on xx/xx/xxxx).

Find a Species

Black Guillemot

Black Guillemot

Introduction

Key Stats

Identification

ID Videos

Winter Auks

Songs and Calls

Call:

Other:

Status and Trends

Conservation Status

Population Size

Population Change

Distribution

Occupied 10-km squares in UK

European Distribution Map

Distribution Change

Change in occupied 10-km squares in the UK

Seasonality

Weekly pattern of occurrence

Movement

Britain & Ireland movement

Foreign locations of birds ringed or recovered in Britain & Ireland

European movements

Biology

Productivity and Nesting

Nesting timing

Egg measurements

Clutch Size

Incubation

Fledging

Survival and Longevity

Lifespan

Survival of adults

Biometrics

Wing length

Body weight

Ring Size

Classification, names and codes

Classification and Codes

Alternate species names

Research

Causes of Change and Solutions

Causes of change

Publications (5)

Combining temperature-depth recorder and GPS data improves identification of foraging habitat in diving seabirds

The status of the UK’s breeding seabirds

Seabird Population Trends and Causes of Change: 1986–2023

Seabird abundances projected to decline in response to climate change in Britain and Ireland

Behavioural responses of non-breeding waterbirds to marine traffic in the near-shore environment

More Evidence

More evidence from Conservation Evidence.com

Partners

Citing BirdFacts

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