The realm of the jackdaw in my garden

A large group of jackdaws is currently reigning supreme in my garden.  They appeared about six weeks ago, and are here every late morning when they spread out across my lawn and forage in the grass and occasionally the flower beds, usually in harmony with one another, but occasionally with minor internal disputes.  Their relationships with other wildlife in the garden is rather less amiable, but on the whole mutual caution seems to rule.  The most I counted in one go was 16 jackdaws, but there are rarely less than 10.  A group of this sort is known as a train or clattering.  One or two individuals sometimes return in the afternoon, but the jackdaws only visit my lawn en masse in the late morning.

The jackdaw is, at first glance, a large, and undistinguished black bird much like a crow, but when observed more closely is a rather beautiful thing.  It has remarkable silver eyes that stand out against the black pupils.  The head and beak are black, but the hood, nape and neck are silvery-charcoal, like a mane, which becomes pure silver in bright sunlight.  They have a self-important rocking-horse motion, but walk one leg at a time, rather than bouncing along on both legs like smaller birds.  Their skinny-looking legs are well able to support their large bodies during periods of extensive walking over the expanse of the lawn.  They use their wings to supplement their legs to pick up speed when seeing off transgressors or moving a safe distance away from their more aggressive family members.  Young jackdaws have brown irises that only become silver grey as they become more mature.

Jackdaws (Corvus monedula) are part of the same 120-species family as crows, ravens, rooks, magpies, and jays, the corvid family, and are the smallest member of that family in the UK, at about 34cm long.  Carl Linnaeus provided the name “monedula,” deriving from the Latin word for money, chosen for the brightness of the things that the jackdaw, like the magpie, is fond of collecting.  Every creature on the planet owes its two-part Latin formal name to Carl Linnaeus (1707-1778).  All living creatures are assigned  these two Latin names, their genus and species.  Biologists have since elaborated this system, and now rely on DNA to establish relationships, but Linnaeus provided them with the basics of the taxonomy that we continue to use.

Sometimes all one can see is the bird’s rear end, because the head is so deeply and busily buried in the grass. Like other members of the corvid family, jackdaws are omnivores.  Whatever they are plucking out of my lawn and flower beds is probably insect life, like leather jackets, worms, beetles, caterpillars and ants.  They are also partial to slugs and small snails, and and supplement their diet with fruit and seeds.  Jackdaws also steal the eggs and offspring of smaller birds and, like all corvids, will eat carrion when they find it.  The diversity of their diet has helped their numbers to rise in Britain.  

Many insect eaters can derive most of their water requirement from this food, and I have not yet seen them (or magpies) drink from any of the bird baths in the garden which the other bird species use frequently, even large ones like pigeons and doves. They may, of course, be sourcing their liquids from outside the garden.

They don’t sing; they squawk and chatter.  It is often a rather disharmonious sound, unappealing to the human ear, nothing like the blissful melodies of the blackbird or thrush.  You can hear a sample on the British Birdsong website here, or the RSPB website here.

Birds that form lifelong monogamous relationships often have the largest brains, relative to their body size, and they are certainly smart, regularly defeating my small-birds-only weight-detecting  winter bird feeder, using every form of trickery at their disposal, including flapping wings madly to hold position whilst poking their heads through the hole to reach the bird seed.  In the days when milkmen left bottles with foil caps by front doors, jackdaws were notorious for pecking through the foil to get to the creamy milk within, thereby rendering themselves seriously unpopular by contaminating and ruining the milk.

Jackdaw eggs in nest. Source: East Norfolk Ringing Group blog

There is no externally visible difference between the male and female.  Jackdaws breed between April and June, raising one brood each year.  Their nests are untidy.  They simply fill a hole or recess with sticks, and may be lined with wool, hair, string or grass and weeds.  A 2021 research paper found that although pairs behaved similarly and generally cooperated to build their nests, their roles were not identical.  Females contribute more to the build of the nest, and call more frequently, but the males are more assiduous guardians of the nest once it is built.  The eggs are blue-grey with dark speckles.  Once the eggs are laid, usually up to a maximum of six or seven, more usually four or five at a time, they are incubated for up to 20 days.  They hatch at different times, with the oldest having a much better chance of survival than the youngest.   The female tends the nest whilst the male sources food and brings it to the female and the chicks.  The chicks remain in the nest for up to five weeks, before leaving the nest and learning to fly and feed for themselves.

Jackdaws on chimneys in Cornwall. Source: Hudson 1908

In the title of the post I referred to the garden as their realm, because as far as I can tell, two generations of the family have been born in one of my chimney pots.  I seem to be sharing with those jackdaws the same pattern of sheltering in the house at certain times of the day and night, and working in the the garden when the weather is nice, or at least dry 🙂  One of the colloquial name for the jackdaw is the “chimney bird” due to their affinity for this particular type of home, which are becoming less available to them year by year, due to chimney caps and central heating.  Fortunately, as well as chimneys and holes in roofs, they also like rock shelves, cliff faces, tree holes and the abandoned nests of bigger birds.  Some will even nest in abandoned rabbit burrows.  The chimney at the front of my house, together with that section of the slate-tiled roof, formed the hub of their activities when the nest was still occupied, but they still use it as a home base, where they  can sit and bicker and gather their energies for the next foray into my garden or, in the afternoons, into the field over the road. Right now, in mid June, the noise in the chimney is confined to mornings and early evenings, meaning that the youngsters are fully fledged and that the family are out all day.

Jackdaws move seasonally.  Family units will focus on a breeding site in the spring and summer, often returning to it in subsequent years, but in the winter they will leave and join communities of several hundred other corvids, not just jackdaws but also rooks and carrion crows, roosting high in trees.  These winter roosts are rarely too far from their breeding grounds.  Communal roosting is both sociable and solitary.  Although the birds gather together in the trees, they are spaced from one another, not huddled together for warmth.  Large roosts attract predators, and although a few losses might be seen as a sacrifice worth making for the benefit of the group as a whole, such as African livestock herds where the elderly, young and weak are picked off.  But herds are on the move, and a roost does not move, making it an easy target for multiple predators to target them.  Still, those perched within the greater group are likely to be protected, and the better positions in the roost are, like other aspects of corvid life, dictated by hierarchy and status.  An additional or alternative explanation is based on corvid intelligence and communication, and suggests that roosts provide a context for learning and for the exchange of information.  What this means in bird terms is obviously very different from what it means to human groups, but there is little doubt that the calls made are a form of communication and signalling.

Konrad Lorenz.  Source: Famous Psychologists

Research into jackdaw behaviour builds on the foundational 1930s work by Konrad Lorenz.  The jackdaw population might have been flattered had it known that Lorenz, a renowned Austrian ornithologist, is also credited today with being the Nobel Prize-winning founder of modern ethology ( the biological study of behaviour), and observed the jackdaw with a view to understanding innate behaviour in animal and human communities.  Lorenz was the first to observe that jackdaw groups operated within a strict social hierarchy based on sex, breeding status and seniority.  

All wild jackdaw couples are monogamous, paired for life.  It makes biological sense that breeding pairs are more important than unattached individuals, and in a social order where the male choses the female, it is inevitable that a single female will be lower in status than a paired female or a single male.   This means that females without partners are at the bottom of the social heap.  This has consequences.  If a female is unpaired, she is disadvantaged, particularly when times are hard.  She is the last to eat, the first to be denied shelter in the nest at times of stress, will be pushed to the risky outside edges of a communal roost, and is not permitted to retaliate when picked on by other members of the community, who may peck at her to reinforce their own status.  Matters change when a female is selected by a male as his mate for life.  Her status is equal to that of her mate, and she then has the authority to treat junior members of the community in the same way that she was herself treated.  

More complex relations occur amongst males, as a 2014 research project discovered, concluding that larger male jackdaws attained higher ranks and that social rank increased with age.  It also suggested that high-ranked individuals had a shorter lifespan suggesting that maintaining or achieving high rank and associated benefits comes at a cost, and also that social rank declined substantially in the last year an individual was observed in the colony, because of deterioration in performance related to age, which acted against the benefits of seniority, knowledge and experience.  Apart from physical size equating to rank, the rest is eerily reminiscent of patterns in human livestock-herding groups operating in marginal conditions in places like the Sahara, where seniority, experience and knowledge are the key priorities for choosing group leaders, because those are the skills that will promote survival.

Jackdaws often come up in the context of “social behaviour” research.  Instead of focusing on which bird is likely to be the most dominant in a particular hierarchy, the focus in this type of research is on how the entire group acts as a decision-making unit.  For example, when big groups roost overnight in huge numbers and then split up into smaller groups during the day to feed in various locations, there is a question about how the decision is taken to take flight.  Research in Cornwall, recording the sounds of bird calls before, during and after they have taken flight is key to this process.  The calls reach an intensity immediately before the birds take to the wing, as though they are declaring a level of confidence that reaches a peak, a threshold that indicates that the group is ready to take to the skies. A major evolutionary advantage would equate to herbivore herd behaviour, creating a block of fast and confusing movement to deter predators, which would otherwise pick off lone individuals with comparative ease.

At least some of this  behaviour can be observed in the garden.  There is plenty of pecking when one jackdaw ranges too close to another, presumably a senior making it clear to a junior or unpaired female that there are boundaries to be observed.  Sometimes a few of them will walk in line, like schoolchildren following a teacher.  For the most part, they are evenly spread across the lawn and only occasionally do a small number bunch in close proximity.

They are perfectly happy to share my lawn with the robins and blackbirds that also forage in the lawn at the same time,  as long as they don’t come too close. On the other hand, war breaks out when a squirrel emerges, quivering all over, its tail tightly curled, pausing to strategize before taking up the offensive and chasing off the jackdaws.  When the magpies arrive, a wary stand-off is practised on both sides.  When the magpies, singly or in a pair, stay at a safe distance all is well, but if the magpies infringe too far, hostilities are quick to erupt.  The magpies will often dive-bomb the jackdaws at such times.  Even though the jackdaws should be able to win the numbers game, they usually take to the wing, but so do the magpies.  It’s a lose-lose scenario.

Transit and mobbing flock patterns. Source: Nature

Jackdaws, like starlings, occasionally form flocks.  Recent research has shown that there are two different types of flocking behaviour: those flying to their winter roosts and those joining forces to scare off potential predators.  In the first case, transit flocking, there is an element of predictability because the size of the winter roost flocks is fixed, and the jackdaws organize themselves in relation to one another in an orderly manner.  In the second case, referred to as mobbing, the sudden gathering to scare off predators is a far more chaotic and unplanned event until the flock has achieved a certain number, when the jackdaws start to behave more like a roosting flock, with their motion through the sky co-ordinated and spatially organized.  Jackdaws flocking before roosting offer some of the most spectacular aerial displays.

The jackdaw has only a faint footprint in myth and history suggesting that whilst an occasional nuisance it has not been sufficiently systematic as a pest to make its mark in folklore and superstition.  Henry VIII, never one to pull his punches, added jackdaws, rooks and crows to the Vermin Act of 1532 in response to poor grain harvest that were blamed, in part, on foraging corvids.  Elizabeth I echoed his in 1566 with another act intended to preserve the nation’s grain production against birds.  Perhaps this reputation for pillaging grain accounts for why they were sometimes considered to be bad luck. Although a jackdaw on a roof might once have been taken to signify a new arrival, it might just as well have been an ill omen, sometimes a portent of death.  Several decades later, in May 1604, Members of Parliament in the London Houses of Parliament were debating the third reading a bill when a young jackdaw flew into the chamber, upsetting a number of those present who interpreted it as a bad omen for the bill. Jackdaws had long been associated with ill fortune.  Although there had ben confidence that the bill would pass, it went on to be defeated by 118 votes to 99. The clerk of the Commons was sufficiently impressed by the incident that he recorded it in the Commons Journal. 

Bodmin Jail. Source: Cornwall Live

In the 19th Century, the jackdaws of Bodmin Jail on Bodmin Moor in southwest England were thought to be on the cusp of fulfilling a curse.  A spinster living in woods on the edge of Bodmin, shunned as a witch, depended on jackdaws to bring her trinkets, and trained them to steal items of value, enabling her to survive.  When she was found guilty of the jackdaw thefts, she was incarcerated in Bodmin Jail, where she died, cursing her jailers, the jail, and the town of Bodmin, whose inhabitants had rejected her so cruelly.  The jackdaws, having followed her to the jail, remained, and the curse stated that “should the last Jackdaw be born at Bodmin Gaol, so the spirits of the condemned shall rise and bring misfortune and chaos to all that reside within.”

The Vain Jackdaw by Harrison Weir in 1881

In literature, a Greek and Roman adage that “the swans will speak when the Jackdaws are silent” (in Latin, tunc canent cygni, cum tacebunt graculi) advises that the wise should speak only when the foolish have finished their chatter.  The jackdaw puts in an appearance in a version of Aesop’s Fables, representing unwise behaviour including vanity and greed.  In The Bird with the Borrowed Feathers, the jackdaw borrows the peacock’s feathers to become one of this superior enclave, but on being recognized as a fraud has the borrowed feathers stripped from him and is so badly mauled that his own species do not recognize him, and reject him.  It is a moral against social climbing.

In the 18th century, A poem by William Cowper (1731-1800) is dedicated to the jackdaw:

There is a bird who, by his coat
And by the hoarseness of his note,
Might be supposed a crow;
A great frequenter of the church,
Where, bishop-like, he finds a perch,
And dormitory too.

Above the steeple shines a plate,
That turns and turns, to indicate
From what point blows the weather.
Look up — your brains begin to swim,
‘Tis in the clouds — that pleases him,
He chooses it the rather.

Fond of the speculative height,
Thither he wings his airy flight,
And thence securely sees
The bustle and the rareeshow,
That occupy mankind below,
Secure and at his ease.

You think, no doubt, he sits and muses
On future broken bones and bruises,
If he should chance to fall.
No; not a single thought like that
Employs his philosophic pate,
Or troubles it at all.

He sees that this great roundabout,
The world, with all its motley rout,
Church, army, physic, law,
Its customs and its businesses,
Is no concern at all of his,
And says — what says he? — Caw.

Thrice happy bird! I too have seen
Much of the vanities of men;
And, sick of having seen ’em,
Would cheerfully these limbs resign
For such a pair of wings as thine
And such a head between ’em.

Perhaps a better known poem about jackdaws is the 19th century The Jackdaw of Rheims by Richard Harris Barham (who used the pen-name Thomas Ingoldsby, 1788 – 1845).  It’s a lengthy affair, so I haven’t reproduced it here, but you can find it on the All Poetry website here.  It is another humourous poem that tells how a jackdaw stole the cardinal’s ring, but wound up being made a saint.

Because jackdaws often favour steeples and holes in roofs of church buildings, the Jackdaw can valued as a holy bird, shunned by the Devil because of its pious choice of residence, a tradition that was particularly prevalent in Wales.  I suspect that those responsible for the care of the churches concerned might have a less charitable view on the subject.

On the whole, history has judged the jackdaw without suspicion but without overt hostility.  Today they are are still legally classified as vermin in the Wildlife and Countryside Act of 1981, and numerous pest control companies offer the removal of jackdaws as one of their services.  This is partly because of the noise and disruption of their chimney, roof and church occupancies (and I can vouch for the fact that they are seriously noisy) but also because of their perceived threat to the conservation of smaller bird populations and the ongoing damage that they can inflict on cereals crops.

There are some 1,400,000 breeding pairs in Britain and in the region of 30 million across Europe.  In 1984, they were first identified in north America. The Big Garden Birdwatch, organized annually by the RSPB, found that jackdaws were ranked 15th in birds observed in English gardens in 2022, and 11th in Welsh gardens.  In both cases most of the birds higher up in the ranking were small varieties, but they also came in behind magpies and wood pigeons.

When I walk out of the back door the jackdaws take to the air without hesitations.  Unlike the blackbirds and the robins that take a look at me, hop a short distance away, and then ignore me, or the sparrows and tits that take instant flight, but only as far as the nearest tree from which they can monitor my activities, the jackdaws are gone.   Although the jackdaws and I share the garden independently, there have been numerous examples of jackdaws having a close affinity with particular humans.  Usually this is after the bird has been injured and cared for by the person with whom the relationship is formed (broken wings seem to be the most common example), but not always.  There’s a great video of a man feeding a jackdaw with a grape at Rhuddlan Castle below, which shows that formidable beak in action (I would be seriously worried for my fingers, but the jackdaw never misses its target):

The tenure of the jackdaws in my chimney will have to end this year after they leave, when the chimney will be cleaned out and capped, but it has been fascinating to have this growing family at both roof and ground level for so long.

Sources:

Books

Bruun, B. 1970. The Hamlyn Guide to the Birds of Britain and Europe.  Hamlyn Publishing

Couzens, D.2004.  The Secret Lives of Garden Birds.  RSPB

Hudson W. H. 1908. The Land’s End. A Naturalist’s Impressions In West Cornwall, Illustrated. D. Appleton And Company.
Available on Project Gutenberg:
https://www.gutenberg.org/files/47990/47990-h/47990-h.htm

Moss, S. 2003. Understanding Bird Behaviour. A Birdwatcher’s Guide.  The Wildlife Trusts

Reader’s Digest Nature Lover’s Library 1981.  Field Guide to the Birds of Britain. Reader’s Digest

Papers

Nicola S. Clayton and Nathan J. Emery 2007. The social life of corvids. Current Biology, Vol.17 No.16.
https://www.cell.com/current-biology/pdf/S0960-9822(07)01494-7.pdf
https://www.academia.edu/23657956/The_social_life_of_corvids

Alex J. Dibnah, James E. Herbert-Read, Neeltje J. Boogert, Guillam E. McIvor, Jolle W. Jolles, Alex Thornton 2022. Vocally mediated consensus decisions govern mass departures from jackdaw roosts. Current Biology, 2022; 32 (10)
https://www.cell.com/current-biology/fulltext/S0960-9822(22)00601-7?_returnURL=https%3A%2F%2Flinkinghub.elsevier.com%2Fretrieve%2Fpii%2FS0960982222006017%3Fshowall%3Dtrue

Nathan J. Emery, Amanda M. Seed, Auguste M. P. von Bayern and Nicola S. Clayton, 2007. Cognitive adaptations of social bonding in birds.  Philosophical Transactions of the Royal Society B (2007) 362, 489–505

Ira G. Federspiel, M. Boeckle, A. M. P. von Bayern and N. J. Emery 2019. Exploring individual and social learning in jackdaws (Corvus monedula). Learning & Behavior volume 47, pages 258–270
https://link.springer.com/article/10.3758/s13420-019-00383-8

Alison L. Greggor, Guillam E. McIvor, Nicola S. Clayton and Alex Thornton 2016.  Contagious risk taking: social information and context influence wild jackdaws’ responses to novelty and risk.
Scientific Reports volume 6, Article number: 27764 (2016)
https://www.nature.com/articles/srep27764

Luca G. Hahn, Rebecca Hooper, Guillam E. McIvor and Alex Thornton 2021. Cooperative nest building in wild jackdaw pairs. Animal Behaviour, Volume 178, August 2021, pp.149-163
https://www.sciencedirect.com/science/article/abs/pii/S0003347221001731

Hangjian Ling, Guillam E. Mclvor, Joseph Westley, Kasper van der Vaart, Richard T. Vaughan, Alex Thornton & Nicholas T. Ouellette 2019.  Behavioural plasticity and the transition to order in jackdaw flocks.  Nature Communications volume 10, Article number: 5174
https://www.nature.com/articles/s41467-019-13281-4

Mioduszewska, B., Schleuning, X., Brunon, A., O’Hara, M., Auersperg, A. M. I., Federspiel, I. G., and von Bayern, A. M. P. 2020. Task aspects triggering observational learning in jackdaws (Corvus monedula). Animal Behavior and Cognition, 7(4), pp.567-588
https://www.animalbehaviorandcognition.org/uploads/journals/29/AB_C_Vol7(4)_Mioduszewska_et_%20al.pdf

P.William Smith, 1985. Jackdaws reach the New World. The first specimen record for North America, with notes concerning the birds’ probable origin. American Birds, Fall 1985, vol.39, no.3
https://sora.unm.edu/sites/default/files/journals/nab/v039n03/p00255-p00258.pdf

Matthew Sparkes 2022. Flocks of jackdaws ‘democratically’ decide when to take flight at once. New Scientist 23rd May 2022.
https://www.newscientist.com/article/2320585-flocks-of-jackdaws-democratically-decide-when-to-take-flight-at-once/

Simon Verhulst, Moniek Geerdink, H. Martijn Salomons, and Jelle J. Boonekamp 2014 . Social life histories: jackdaw dominance increases with age, terminally declines and shortens lifespan. Proceedings of Biological Science, September 22nd 2014; 281(1791): 20141045.
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4132676/ 

Lies Zandberg, Jolle W. Jolles, Neeltje J. Boogert, Alex Thornton 2014. Jackdaw nestlings can discriminate between conspecific calls but do not beg specifically to their parents. Behavioral Ecology, Volume 25, Issue 3, May-June 2014, pp.565–573
https://academic.oup.com/beheco/article/25/3/565/513806

Websites

10 Things Wrong with Environmental Thinking (blog)
Spat out of Nature by Nature: Konrad Lorenz and the Rise and Fall of Ethology
http://10thingswrongwithenvironmentalthought.blogspot.com/2012/07/spat-out-of-nature-by-nature-konrad.html

Birds in Cheshire and Wirral
Jackdaw (Corvus monedula)
http://www.cheshireandwirralbirdatlas.org/species/jackdaw-wintering.htm

Bodmin Jail
The Jackdaws of Bodmin Jail
https://www.bodminjail.org/blog/historical-tales/the-jackdaws-of-bodmin-jail/

British Garden Birds
(Eurasian) Jackdaw
https://www.garden-birds.co.uk/birds/jackdaw.html

Country Life
11 Things you never knew about the jackdaw
https://www.countrylife.co.uk/nature/jackdaw-bird-just-loves-people-178185

The History of Parliament
Parliament and Superstition: A Jackdaw in the House of Commons, 1604
https://thehistoryofparliament.wordpress.com/2019/05/09/parliament-and-superstition-a-jackdaw-in-the-house-of-commons-1604/

The Nobel Prize
Konrad Lorenz – Facts (Sat. 18 Jun 2022)
https://www.nobelprize.org/prizes/medicine/1973/lorenz/facts/

RSPB
Jackdaw
https://www.rspb.org.uk/birds-and-wildlife/wildlife-guides/bird-a-z/jackdaw/
Big Garden Birdwatch
https://www.rspb.org.uk/get-involved/activities/birdwatch/

Wildlife Trust
Jackdaw
https://www.wildlifetrusts.org/wildlife-explorer/birds/crows-and-shrikes/jackdaw

World Birds
Jackdaw symbolism and meaning
https://worldbirds.com/jackdaw-symbolism/

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