Jackdaw  (Corvus monedula)

Jackdaw

Facts

Kingdom Animalia
Phylum Chordata
Class Aves
Order Passeriformes
Family Corvidae
Genus Corvus (1)
Size Wingspan: 64-73 cm (2)
Length: 30-34 cm (2)

Status

Receives general protection under the Wildlife and Countryside Act 1981 (3). Included in the Birds of Conservation Concern Green List (low conservation concern) (8).

Description

The jackdaw is a lively, diminutive member of the crow family (5). It appears to have totally dark plumage from a distance, but on closer inspection it can be seen that it is dark grey in colour with a lighter grey nape and sides of the neck (2). The beak is short and slender, the eyes are a unique pale blue, and it walks with a quick 'jaunty' step (6), all of which allow this bird to be distinguished from the carrion and hooded crows or the rook (2). Males, females and juveniles are similar in appearance (2). The name 'daw' for this bird has been used since the 15th century; it is probably imitative of the call (4), but also means 'simpleton' (6). 'Jack' is often used for small animals, and, like knave, means rogue, yet it may also be derived from another call, 'tchack' (6). This bird is indeed smaller than both the rook and the carrion crow, and is a renowned thief (4).

Range

Widely distributed throughout Britain, but scarcer in upland areas (5). It is also widespread throughout western Europe (6). Scandinavian populations migrate to England, Scotland and the Low Countries for the winter (6).

Habitat

Breeds in buildings and cavities in houses, as well as in parks, woodlands with hollow trees, and on sea cliffs (2).

Biology

The jackdaw is a highly sociable species outside of the breeding season, occurring in flocks that can contain hundreds of birds (6). Within flocks there is a strict hierarchy, with a head bird (6). Occasionally the flock makes 'mercy killings', in which a sick or injured bird is mobbed until it is killed (6).

The jackdaw typically feeds on the ground, taking insects and insect larvae, young birds, fruit and acorns (6). This is a playful species, performing aerobatics such as turning over in strong winds and diving; occasionally entire flocks may perform such displays at the same time (6).

Males and females pair up in their first year of life, but they do not begin to breed for another year; the pair remains closely tied for life (6). Nests are usually constructed in some type of crevice, the pair drops sticks into the crevice until some become lodged; the nest is then built on this platform (6). This behaviour has often led to chimneys being blocked and even nests, with the jackdaw present, crashing down into fireplaces (4). The pair defend their nest vigorously against intruding jackdaws (6). 4-6 greenish-blue eggs are laid and incubated for up to 17 days by the female (6). Both parents feed the chicks for around 30 days (6).

Threats

Although wild birds are protected under the Wildlife and Countryside Act 1981 (7), jackdaws may be killed under a general licence provision by authorised persons (9). Jackdaw numbers have increased by over 50% since 1975 (10).

Conservation

No conservation action is targeted at this species.

Further Information

See the RSPB website:
http://www.rspb.org.uk

Authentication

Information authenticated by the RSPB:
http://www.rspb.org.uk/

Larvae: stage in an animal's lifecycle after it hatches from the egg. Larvae are typically very different in appearance to adults; they are able to feed and move around but usually are unable to reproduce.

References

  1. National Biodiversity Network Species Dictionary (July 2002):
    http://www.nhm.ac.uk/nbn
  2. Mullarney, K., Svensson, L., Zetterstrom, D., & Grant, P.J. (1999) Collins Bird Guide. HarperCollins Publishers Ltd, London.
  3. Naturenet (July 2002):
    http://www.naturenet.net/law/wcagen.html
  4. Greenoak, F. (1979) All the birds of the air; the names, lore and literature of British birds. Book Club Associates, London.
  5. Lack, P. (1986) The Atlas of Wintering Birds in Britain and Ireland. T. & A. D. Poyser Ltd, Calton
  6. Bruce Wilmore, S. (1977) Crows, jays, ravens and their relatives. David and Charles (Publishers) Ltd, London.
  7. DEFRA. Vertebrate Wildlife Management (July 2002):
    http://www.defra.gov.uk/wildlife-countryside/vertebrates/gen-licence.htm
  8. RSPB (2003) The population status of birds in the UK:
    http://www.rspb.org.uk/Images/5_20625.pdf
  9. RSPB (2003): Pers. comm.