J is for Jackdaw

Jackdaw (Corvus monedula)

It wouldn’t be right to obsess about birds without mentioning a corvid (member of the crow family). Renowned in science for their incredible intelligence and behaviour and in fiction for the folklore they are steeped in.

Of the large, black birds in the genus Corvus, the jackdaw is one of the most recognisable*. It is the smallest of the lot, with a grey bobble head, black cap, pearly white eye and of course it’s distinctive yapping call. They can be found pretty much everywhere except the barren highlands, both as townies and farmland birds, where they are one of the few species benefitting from large intensive fields. They sometimes visit gardens, especially during the breeding season and winter when there is pressure to find food¹.

The Jackdaw’s name attracts a lot of interest since it includes a human one. It is usually explained as imitating their call, but the name is also used to refer to small stature such as the jack snipe (Lymnocryptes minimus).  The ‘daw’ part has a linguistic meaning, referring to ‘someone in low esteem’ possibly due to being common,  and given to thieving precious objects ² (though ‘stealing’ is only practiced by captive corvids).

Like other corvids, jackdaws will eat pretty much anything. Though their stubby beak prevents them probing the soil like other Corvus, it is a powerful tool . I have seen them smashing open conker (Aesculus hippocastanum) shells. They do eat the eggs and young of other birds occasionally, and are apparently useful for controlling feral pigeons in this way³.On garden feeders they can be surprisingly acrobatic.

An acrobatic jackdaw on our fat ball feeder last winter

Jackdaw life revolves around the social scene. They live in flocks, foraging, flying, roosting and nesting together in groups which are often entertaining to watch. Esther Woolfston, admirer of corvids describes how they “dive with their black and sinuous flight, swoop, loop and spiral” through castle ruins⁴ . Within these groups there is a complex social hierarchy, and these interactions were studied very early on, in the 1930’s by Konrad Lorenz. He found that whilst bachelors are dominant over spinsters, females gain equal status as their mates once they pair up.  Individuals use this strict hierarchy, coupled with a varied body language to avoid physical fighting and dominant males often act as peacekeepers⁵.  If a fight does break out, the whole colony gets excited and surrounds them like children at a playground tussle⁶.

The advantage of group living for jackdaws is beyond simple safety in numbers. Group members actively look out for each other. If one is grabbed by a predator, the rest will bear down on the enemy, cawing angrily⁶. Even the passing resemblance of a fluttering black plastic bag to a struggling jackdaw can provoke them⁷. One of their main predators are female Sparrowhawks (Accipiter nisus), which can just about restrain one jackdaw let alone an angry flock.

 Like other corvids, jackdaws mate for life and pairs always stick together, even within the larger flock. They share nesting duties equally, and feed and preen one another. Remarkably, unlike many other ‘monogamous’ birds, Jackdaws don’t cheat on their partners, even though they have plenty of flock mates to choose from⁸ (Male rooks Corvus frugilegus, by contrast, regularly take advantage of neighbouring nesting females)⁹. Young jackdaws even generously offer food to their peers, which helps them make friends¹⁰.

Jackdaws may even be social towards other species. They often roost together with rooks, and the resulting evening flocks are a spectacle of sight and sound. Underlying these are strict rules governing the position of the species and individuals¹¹. Fascinatingly, I met a birdwatcher  who claimed he had seen inter-species play of ‘catch the stick’ between rooks and jackdaws^ᵻ.

The only time Jackdaws show real hostility is when nesting. They nest in holes, a naturally scarce resource, so there is intense competition between pairs. This year’s ‘Springwatch’ focused on a Jackdaw nest that another pair were determinedly trying to oust by harassing the chicks and stealing nesting material. They commonly nest in boxes meant for owls or kestrels (Falco tinnunculus , and will doggedly defend their spot against them.  Most famously, they will use chimney pots, dropping down sticks until they form a platform, one pile measured 2.4m across and 1m high¹. See one here.

Astounding footage of a Jackdaw tenaciuosly defending a next box against a Kestrel that wants it for itself.

With a complex social life and pugnacious attitude, the Jackdaw is definitely deserving of higher esteem than its name suggests. It has been a fascinating bird to research.

*The genus also includes the raven C.corax, Carrion crow C.corone, Hooded crow C.cornix and the Rook C.frugilegus in the UK.

^ᵻ This is not implausible, there are lots of observations of corvids playing.

References

1-BTO (2012). The Crow next ‘daw’: Jackdaw. BirdTable. Available from: http://www.bto.org/sites/default/files/shared_documents/gbw/associated_files/bird-table-70-jackdaw-article.pdf

2- Fransesca Greenoak. (1979) All the Birds of the Air. A. Brown and Sons.

3- Percy Trett. (No date) Jackdaw. Birds of Britain. Available from:  http://www.birdsofbritain.co.uk/bird-guide/jackdaw.asp

4- Esther Woolfston. (2008) Corvus: A Life with Birds. Granta Publications.

5- Konrad Lorenz . (1931) Beiträge zur ethologie sozialer Corvidae. Journal of Ornithology  80, 50-98. Cited by: A. Röell. (1978) Social Behaviour of the Jackdaw, Corvus monedula, in Relation to Its Niche. Behaviour,  64 (1/2), 1-124. Available from: http://www.jstor.org/stable/4533862

6-A. Röell. (1978) Social Behaviour of the Jackdaw, Corvus monedula, in Relation to Its Niche. Behaviour,  64 (1/2), 1-124. Available from: http://www.jstor.org/stable/4533862
      - (A thorough Paper on Jackdaws and their social behaviour)

7- Konrad Lorenz. (1952). King Solomon’s Ring: New Light on Animal Ways. (Translated from the German by Marjorie Kerr Wilson). Clay and Company, Suffolk.

8- Auguste M. P. von Bayern, Selvino R. de Kort, Nicola S. Clayton and Nathan J. Emery. (2007) 733The role of food- and object-sharing in the development of social bonds in juvenile jackdaws (Corvus monedula). Behaviour, 144 (6), 711- 733. Available from: http://www.jstor.org/stable/4536473

9- Dominic Couzens. (2012) Garden Birds Confidential. Bounty Books.

10- I. G. Henderson, P. J. B. Hart, and T. Burke. (2000). Strict monogamy in a semi-colonial passerine: the Jackdaw Corvus monedula. Journal of Avian Biology, 31 (2), 177–182.
Mentioned by:  Dominic Couzens. (2012) Garden Birds Confidential. Bounty Books.


11- University of Exeter. (2013). How birds of different feathers flock together. Available from: http://www.exeter.ac.uk/news/research/title_271250_en.html