In Crown Prince Rudolph's day, the Corn Crake was a common meadowland bird in the Danube wetlands. Today, the endangered Corn Crake is one of the ornithological highlights of the Donau-Auen National Park. This rare bird is usually concealed in damp meadows with lush high grasses. And although it is rarely seen, its loud, far-carrying cry is heard at night. The dramatic decline in the Corn Crake population is due mainly to the destruction of damp meadows and intensified agricultural activity: early mowing and large, efficient machinery prevent successful reproduction. In recent years, the Corn Crake has become the European flagship species among endangered meadow birds and as such, has attracted widespread attention. Within the framework of the LIFE Nature Project, the re-colonization of the Corn Crake in the Donau-Auen National Park has been supported with carefully targeted measures.
Corn Crakes "sing" more or less uninterrupted from dusk to dawn. The repeated rasping diphthong "crrek crrek" which gave rise to this species' scientific name ("Crex crex") may be up to 110 dB and can be heard kilometres away. Like other rails and crakes of the Rallidae family, the Corn Crake looks like a narrow-breasted, long-legged and long-necked game bird.
About one-and-a-half times larger than a starling, at first glance the Corn Crake has brownish plumage. But upon closer inspection, one sees the pretty blue-grey band over the eye, grey on the breast and black-brown stripes on white along the side. The most visible characteristic – if one has the chance to see it in flight, e.g. after having been flushed during mowing – are the red-brown wings. The sexes cannot be differentiated. Like all crakes, the chicken-like chicks are deep black until they are around two weeks old.
The northerly geographic range spans from southern Scandinavia to northeast Italy and the Black Sea; the southern geographic range from the Pyrenees to Central Siberia. The highest European incidence is in Russia, White Russia and Ukraine. As it was in Austria, the Corn Crake used to be common across all of Europe around the turn of the previous century; up until the 1970s the species could still be sighted frequently in most Austrian provinces. Today, the range is limited to Lower Austria, in particular in the Vienna Woods, Vienna Basin with the Danube wetlands, March-Thaya wetlands and the central Waldviertel ("Forest Quarter"). Important breeding grounds still exist in Upper Austria (especially Freiwald), Styria (Enns Valley) and Vorarlberg (Rhein Valley).
Endangerment and Conservation Status
The Corn Crake is critically endangered in Austria. In addition to the Great Bustard and the Ferruginous Duck, the Corn Crake is the only breeding bird in Austria which is also endangered globally. Its catastrophic decline started with the massive loss of habitats through the destruction of damp meadows (drainage, planting of maize). Starting around 1950, intensified agricultural activity brought about the complete collapse of the population. Earlier and earlier mowing (silage-cutting) and faster and faster harvesters have been responsible for the nearly 100% failure of broods. Increased fertilization also leads to the depletion of habitats by eliminating insects, its source of food, but also through the creation of impenetrable vegetation in the meadows. The survival of the Corn Crake in Central and Western Europe is now dependent on targeted conservation measures (such as mowing only at the end of July, and mowing from the centre of the meadow outwards). In some areas of Austria, and particularly in Lower Austria, conservation projects carried out by BirdLife Austria and financed by provincial governments have been able to contribute significantly to the recovery and/or stabilisation of the Corn Crake population. Protecting this rare meadow bird also benefits a multiplicity of other endangered plants and animal species.
Like other rails and crakes, the Corn Crake is diurnal. A quick runner, it hunts mainly invertebrates (beetles, grasshoppers, earthworms etc.), always hidden in thick vegetation, and can cover astonishing stretches of ground. The Corn Crake over-winters in South and East Africa. In May, immediately after its arrival in the breeding range, the male "sings" intensively in order to attract a female. In this way potential competitors are discouraged from entering its territory, which will be defended vehemently if necessary. Corn Crake pairs remain together only a few days, as the female is capable of finding sufficient nourishment to support the brood on her own. The male thus attempts to win yet another partner ("sequential polygyny"). Buried deep in the grass, the nest holds a typical clutch of 8-12 eggs. The chicks "flee" the nest quickly, and can run and eat from the start, yet allow themselves to be fed by the mother. After only 12 days the chicks are self-sufficient and the female will normally produce a second brood. After the breeding season concludes, the Corn Crake migrates alone to its winter quarters, usually in September.
The reproduction performance of the Corn Crake is unique among migratory birds, and even more so considering its body size. Despite its very short "guest appearance" in the breeding area, females are capable of raising two broods per season. Yet its life is a rather short one, with a life expectancy of 1-2 years on average, similar to a Great Tit.