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Crex

Crex is a small genus of birds in the rail family. It contains two species, the corn crake, C. crex, which breeds across Europe and Asia and winters in southern Africa, and the African crake, C. egregia, which migrates within Africa. Both are short-billed rails with blackish-brown upperparts, mainly blue-grey underparts, and barring on the flanks. The corn crake is significantly larger than its relative, and has a distinctive chestnut patch on its wings. Unusually for their family, these are birds of dry habitats rather than wetlands; the Eurasian species mainly breeds in hay meadows, and the African crake in dry grassland. The African crake is sometimes given its own genus, Crecopsis, but is now more usually placed in Crex. Both species have distinctive loud grating calls used for advertising and territorial purposes in the breeding season, although the corn crake is silent on its African wintering grounds. They are mainly active during the day; they walk with a high-stepping action, and when disturbed they can run swiftly through grass or fly a short distance to cover. Migration takes place at night, and the ability to undertake these journeys is innate, not learned from adults. The nest is a shallow cup of grass lined with finer vegetation and built in a well hidden depression. The precocial chicks leave the nest soon after hatching, and fledge after four to six weeks. These are ground-feeding omnivores, but mainly eat invertebrates. They may be killed by a variety of mammals and large birds, and infected by parasites. The two Crex species have huge breeding ranges and large populations and are classed as least concern on the IUCN Red List. The corn crake was formerly classified as near-threatened because of serious declines in western Europe, but improved monitoring shows that numbers have remained stable further east in Russia and Kazakhstan. In much of the western half of the corn crakes breeding range, there have been long-term declines that are expected to continue. The main cause of the decline is the loss of nests and chicks from early mowing. Haymaking dates have moved forward in the past century due to faster crop growth, made possible by land drainage and the use of fertilisers, and the move from manual grass-cutting using scythes to mechanical mowers. Loss of habitat is the other major threat to the corn crake. Drained and fertilised silage fields are less suitable for breeding than traditional hay meadows. In western Europe the conversion of grassland to arable land has been aided by subsidies, and further east the collapse of collective farming has led to the abandonment and lack of management of much land in this important breeding area.