They also feed heavily on earthworms when grain is not available. This has not made farmers love them, but modern research suggests that they do more good through consuming pests than they do harm by consuming grain. They will also eat acorns and pine kernels. Rooks are more omnivorous than other members of the genus, with more than 50% of their diet being composed of grains. Rook is an Anglo-Saxon name for the bird’s call. Rooks, Corvus frugilegus, have a distribution that stretches from the UK to Japan, but are absent from truly tropical climes as well as from the colder north. Ecologically it is similar to the Common Jackdaw. The Damian or Daurian Jackdaw ( Corvus dauricus) is the only other species of Jackdaw.ĭistinguished by its whitish breast and its far eastern distribution from eastern Russia to Japan. Jackdaws are unique among corvids in their pale blue eyes. Moulting starts for the adult while the young are still in the nest and lasts 105 days. Incubations lasts 16-20 days, taking longer the further north the population is located.īoth parents feed the young on a diet consisting mostly of invertebrates. The female incubates and the male feeds her. Both partners build the nest and 4-6 pale greenish-blue, lightly spotted eggs are laid. Nesting starts in March to May depending on latitude. Jackdaws are not sexually mature until their second year. More northerly populations are migratory, however from Britain southwards they are generally more sedentary – though some British populations do migrate. They are absent from Pakistan and India though. Jackdaws occur across most of Europe, the Middle East, Russia and Asia to about lake Biakal. Nowadays however we know that Jackdaws, like all the Corvus genus are not simpletons but among the most intelligent of birds. The common English name arises from the ancient word ‘Daw’ meaning a simpleton and ‘Jack’ based on their ‘tchack’ call. The Romans called them Monedula, which is now their species name. Western Jackdaw, Coloeus monedula perches on one leg They have taken advantage of man’s ability to increase their available food supplies and nesting sites – since farming began and perhaps even before. Jackdaws, like most other corvids, have adapted well to living with mankind. This is a social pecking order, in which each bird knows all the other birds and its relationship to them. Within a colony there is a head bird and a second bird, etc. Jackdaws are socially monogamous, mating for life. Konrad Lorenz, a well-renowned behavioural ecologist, says of Jackdaws “few birds – indeed few of the higher animals – possess so highly developed a social and family life”. Jackdaws ( Corvus monedula) are the smallest and most social of the genus.
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