Birds
Jackdaw
Corvus monedula · also called Western jackdaw, Eurasian jackdaw
The jackdaw is the small, quick, grey-hooded crow that struts across a lawn, calls a sharp tchack from a chimney pot, and joins the swirling black clouds of birds that gather over a roost wood at dusk. It is the most social of the European crows, and one of the most closely bonded, pairing for life before it is even old enough to breed.
Overview
Corvus monedula is the smallest European crow, about 34 to 39 cm long, black with a grey nape and shawl and a distinctive pale, staring eye. It lives across Europe, North Africa, and western Asia in farmland, parkland, sea cliffs, villages, and towns, and it eats an omnivore’s mix of invertebrates, grain, fruit, scraps, and carrion.
A flock bird
Jackdaws are social all year, nesting in loose colonies, feeding in groups, and gathering into large communal roosts at dusk, often mixed with rooks. Pairs form in the first year and stay together for life, sharing a single rank in the flock’s pecking order — a system Konrad Lorenz described in detail from his free-flying colony, work that helped found the science of animal behaviour.
Chimneys and curiosity
The jackdaw is a cavity nester that uses tree holes, cliff crevices, ruins, and very often chimneys, sometimes dropping enough sticks to block a working flue. Its folklore reputation as a thief of shiny objects is mostly a myth — wild jackdaws tend to be wary of unfamiliar bright items — though the birds are genuinely inquisitive problem-solvers.
Status
The jackdaw is Least Concern and increasing across Europe, one of the more successful crows, at home on farmland and in towns alike.
Jackdaw: common questions
How do you tell a jackdaw from a crow or a rook?
Size, shape, and the eye. The jackdaw is the smallest, about the size of a pigeon, with a short stubby bill, a grey wash over the nape and neck, and a pale, staring iris. A carrion crow is larger and all black with a heavier bill and a dark eye. A rook is larger still, black with a purple sheen, and has a bare greyish-white patch of skin at the base of a longer, pointed bill, plus loose feathering on the thighs that gives a baggy-trousered look. In flight the jackdaw is quicker and more agile with faster wingbeats, and its call, a sharp, clipped "tchack" or "kya", is quite different from the crow's harsh caw or the rook's drawn-out "caaah".
Why do jackdaws nest in chimneys, and is it a problem?
Jackdaws are cavity nesters that naturally use holes in trees and crevices in cliffs, and a chimney is simply a tall, sheltered, predator-safe cavity that suits them very well, especially in towns where tree holes are scarce. The birds drop sticks into the flue until some lodge and form a platform, then build the nest on top. In an unused or capped chimney this is harmless, but in a working one the pile of sticks can block the flue, creating a fire risk and a carbon monoxide danger, and occasionally a bird or nestling falls right down into a room. Fitting a chimney cowl or cage before the breeding season is the usual solution, and it is best done outside the nesting period.
Are jackdaws really attracted to shiny things?
The reputation is old and only partly deserved. Jackdaws, like other crows, are curious and will pick up and examine small objects, including bright or metallic ones, and captive birds sometimes hoard oddments, which is where the folklore of the thieving jackdaw comes from. But controlled tests have found that wild jackdaws are, if anything, wary of unfamiliar shiny items rather than drawn to them, and there is no good evidence that they seek out jewellery or coins in the way stories suggest. The birds are genuine problem-solvers and tool-investigators, so the interest in objects is real, but the specific idea of a magpie-or-jackdaw obsession with treasure is largely a myth.
Do jackdaws mate for life?
Yes, and unusually thoroughly. A jackdaw pair generally forms in the bird's first year of life, well before either partner is old enough to breed, and once formed the bond is kept for life, with the two birds staying close, preening each other, and passing food. The pair also shares a single position in the flock's dominance order, so when a low-ranking female pairs with a high-ranking male she immediately rises to his rank, a pattern Konrad Lorenz documented in detail. Divorce is rare, and a bird that loses its mate may not pair again for a long time. This lifelong, jointly-ranked partnership is a large part of what makes jackdaw society so tight.