Diagnoza

Medium size with length 24–30 cm; wingspan 40–53 cm, wing folded 13–15 cm, tail 4–5 cm, body mass of male 210 g and female 138–158 g (Sokołowski 1977; Taylor & Kirwan, 2019);  plumage of the upper parts of body is buff with dark spots, the underside grey-white, wings rusty-brown; sexual dimorphism is hardly visible, the female has a slightly warmer colouration, buff-yellow upper body and narrower and darker gray streaks on the eye, sometimes also less gray color on the cheeks, neck and breast; outside the breeding season, the top plumage of the corncrake becomes more brown and the gray elements fade; some populations differ markedly in coloration, such as the more buff birds from Kazakhstan (proposed to be treated as a separate subspecies of C. c. similis, but this was not accepted); immature birds resemble adult birds but probably have less extensive banding on the upperwing coverts; juvenile individuals also resemble adult birds, but they have narrower, more yellowish feathers in the upper part of the body, also less striping on the upperwing coverts, and the gray color of the sides of the head and breast is replaced by buff; juveniles also have a darker iris and dark gray legs and feet (grayish-pink in adults); chicks are covered with black down.

Porównanie

It clearly differs in plumage color and habit from other rails; the most closely related species - African Corncrake Crecopsis egregia and crakes (Porzana spp) are smaller and have a black and white striped underside of the body; there are also clear osteological differences between the genera; in size, shape and color of plumage it may resemble the partridge Perdix perdix, from which it differs, however, in many osteological features (narrow sternum and pelvis) and silhouette (body flattened mediolaterally); in several ways, the corncrake humerus resembles the species Pastushkinia zazhigini (initially placed in the genus Crex) from the Early Pliocene (4.9-3.2 Ma) of western Mongolia; however, the corncrake lacks the unusual flat surface at the distal end of the humerus, which is characteristic of the genus Pastushkinia (Zelenkov 2013).

Autekologia

It inhabits vast meadows with clumps of shrubs, both dry and wet, including alpine meadows (up to 3000 m above sea level), the edges of swamps and clearings created after felling trees in forests; habitat must not be too wet or too dry and must be covered with not too high, dense vegetation up to a height of approx. 50 cm; locally, it also inhabits agricultural fields (e.g. cereals, potatoes and fodder plants); on wintering grounds, they stop mainly in dry grasslands and savannahs, often in areas damaged by fires during the dry season; also found in dry and wet grass (0.3–2 m high), neglected farmland, airports, golf courses, suburban gardens; wet sedges, shallowly covered with shallow water, and in reed beds; it leads a very secretive lifestyle and is hidden in dense vegetation almost all the time; after occupying a given area, it usually creates a kind of corridors among the vegetation, enabling noiseless movement; most often, the presence of the corncrake can be determined only by the characteristic mating call of the males, from which the name of the species comes; birds also communicate with contact calls, and recent research has shown that they can be used to distinguish between the sexes of birds.
 Breeding period: IV-VIII; polygamous, in Europe approx. 50% of males change territories during the breeding season (Budka et al. 2015); nest on the ground, in dense vegetation; a shallow goblet of grass, weeds and blackberries lined with dry leaves; outer diameter 12-15 cm; depth of 3–4 cm. Eggs: 6-14; only the female incubates 16–19 days; the chicks leave the nest soon after hatching and feed on their own after 3-4 days; fully feathered and flightable after 34–38 days.
Breeding grounds leave between August and October and returns to them in April-May (depending on the place of occurrence).
 The food consists of earthworms, molluscs, isopods, two-armed beetles, spiders and insects, as well as small frogs, small mammals and birds, as well as green parts of plants and seeds (especially grasses and cereals). The diet on wintering grounds is similar. Most active at dawn and dusk, after rain and during light rainfall (Taylor & Kirwan 2019).

Występowanie geograficzne

Eurasia - from France, the British Isles and southern Scandinavia through central and eastern Europe to the north-west China, Mongolia and Russia, reaching as far as Lake Baikal; long-distance migrant; wintering grounds in south-east Africa - from southern D.R. Congo and southern Tanzania to the south-east South Africa; in western Europe, numerous sightings were recorded from the 12th-2nd, especially in the 19th century, when the breeding population was much larger (Taylor & Kirwan 2019); high dispersibility; during migrations quite often blown by the wind, stray birds were found in the Canary Islands, Azores, Madeira, Iceland, Greenland (approx. 20 records), in North America (approx. 17 records), in the Caribbean (Bermuda; Saint Pierre and Miquelon), on W. Fernando de Noronha, Brazil; in India, Afghanistan, Pakistan, Sri Lanka, Andaman Islands, Nicobar Islands, Seychelles, Prince Edward Island, Vietnam and Australia, New Zealand, Japan and many African countries (Libya, Mauritania, Mali, Niger, Chad, Nigeria, Somalia , Ivory Coast, Ghana, Cameroon, Gabon, Congo, Angola, Namibia).
In Polish literature, the oldest mentions of the corncrake are in the works of Mateusz Cygański (Cygański 1584) and Gabriel Rzączyński (Rzączyński 1721), but there is no information about the population in the country; oldest information can be found in the work of W. Taczanowski (1819-90), where the author states: "In the Kingdom of Poland it is very common everywhere, but not everywhere equally abundant" (Taczanowski 1882).
Currently, in Poland, a moderately numerous species with uneven dispersion and population estimated at 30-48 thousand. males. It is most numerous in the eastern part of the country, while in the west it is a rare bird. Long-term trends in the number of corncrake in Poland are not fully known, but their numbers have certainly increased recently (Chylarecki et al. 2018).

Zasięg czasowy

The oldest fossils most likely belonging to the corncrake come from the Early Pleistocene (2.5 - 0.78 Ma) of Ukraine, the Czech Republic and Romania; the oldest certain remains of this species come from the Early Pleistocene of Spain (0.9-0.7 Ma) and the Late Pleistocene and Holocene of Italy, Jordan, Romania, Poland and Great Britain (Mlikovsky 2002); in Poland, the remains of the corncrake were found in as many as 15 Pleistocene sites (Bocheński et al. 2012), the oldest of which come from the cave in Biśnik and are dated 300-250 thousand years ago. years ago (for the measles glaciation); There are also known remains from archaeological excavations, such as the site in Stradów, dated to the 7th-11th century (Tomek 1984).

Materiały muzealne

Literatura

BirdLife International 2016. Crex crex. The IUCN Red List of Threatened Species 2016: e.T22692543A86147127

Bocheński, Z., Bocheński, Z.M. and Tomek, T. 2012. A History of Polish Birds. 68-69 pp. Institute of Systematics and Evolution of Animals. Polish Academy of Sciences, Kraków.

Budka, M., Wojas, L., and Osiejuk, T.S. 2015. Is it possible to acoustically identify individuals within a population? Journal of Ornithology 156 (2): 481–488.

Chylarecki P., Chodkiewicz T., Neubauer G., Sikora A., Meissner W., Woźniak, B., Wylegała, P., Ławicki Ł., Marchowski, D., Betleja, J., Bzoma, S., Cenian, Z., Górski, A., Korniluk, M., Moczarska, J., Ochocińska, D., Rubacha, S., Wieloch, M., Zielińska, M., Zieliński, P. and Kuczyński, L. 2018. Trendy liczebności ptaków w Polsce. GIOŚ, Warszawa.

Cygański, M. 1584. Myślistwo ptasze, w którym się opisuje sposób dostawania wszelakiego Ptaka. 000 pp. Drukarnia J. Siebeneicher, (wyd. bezimienne, I połowa XVII w).

Mlikovsky, J. 2002. Cenozoic birds of the world, part 1: Europe. 000 pp. Praha, Ninox Press.

Rzączyński, G. 1721. Historia naturalis curiosa Regni Poloniae, Magni Ducatus Lituaniae annexarumque provinciarum in tractatus XX divisa. 000 pp. Sandomierz.

Sokołowski, J. 1977. Ptaki Polski. 000 pp. WSiP Warszawa.

Taczanowski, W. 1882. Ptaki Krajowe. Tom 2. 000 pp.  Akademia Umiejętności. Kraków

Taylor, B. and Kirwan, G.M. 2019. Corncrake (Crex crex). W: del Hoyo, J., Elliott, A., Sargatal, J., Christie, D.A. & de Juana, E. (red.). Handbook of the Birds of the World Alive. 00-000. Lynx Edicions, Barcelona.

Tomek T. 1984. Szczątki ptaków z wczesnośredniowiecznej osady w Stradowie [Bird remains from an Early Mediaeval settlement at Stradów]. Acta Zoologica Cracoviensia 27(7): 121-126.

Zelenkov, N.V. 2013. New finds and revised taxa of early Pliocene birds from Western Mongolia. In: U.B. Göhlich & A.B. Kroh (Eds.) Paleornithological Research 2013. Proceedings of the 8th Meeting of the Society of Avian Paleontology and Evolution in Wien, 153-170. Naturhistorisches Museum Wien.