Behaviour The species is a long-distance migrant (Del Hoyo et al. 1996). It breeds during the months of April-August, with nests generally well separated but sometimes only 20-55 m apart from one another (Taylor and van Perlo 1998). It is sequentially polygynous, with some males moving a considerable distance to new singing areas (Green et al. 1997). A male's territory may encompass several nests (Taylor and van Perlo 1998), and local concentrations of breeding birds therefore sometimes occur (Taylor and van Perlo 1998). The species normally produces two broods per year. It begins to leave its breeding grounds in August, with a peak in September (Cramp and Simmons 1980), and arrives on its African wintering grounds in November-December (Cramp and Simmons 1980). It migrates at night, travelling at low altitude (Del Hoyo et al. 1996). During migration it sometimes travels in pairs (Cramp and Simmons 1980), occasionally forming groups of around 20-40 individuals (Taylor and van Perlo 1998), and diurnally resting flocks may contain several hundred birds (Taylor and van Perlo 1998). It occurs solitarily during the non-breeding season, individual birds holding territories of 4-9 ha (Taylor and van Perlo 1998). The return migration begins in late February or March, and the breeding grounds are occupied from mid-April (Cramp and Simmons 1980). Habitat Breeding The species breeds in open or semi-open habitats, mainly meadows with tall grass. The original breeding habitat would almost certainly have been riverine meadows of Carex-Iris-Typhoides and alpine, coastal and fire-created grasslands with few trees or bushes present (Green et al. 1997). The species is now strongly associated with agricultural grassland managed for the production of hay (Barnes 2000). Suitable habitats include moist, unfertilised grassland and regularly cut meadows in areas of low-intensity agriculture where vegetation grows tall in summer. Across its European range, hay or silage fields in valleys liable to flooding seem of most importance, but birds also breed in hay and silage fields in subalpine areas. Wetlands and marsh edges may act as important refuges when drier habitats are unsuitable. Males are also found singing in clear-cuts in forest, pastures and young conifer plantations. Singing males can regularly be heard in fertilised meadows or fields sown with cereals, but successful reproduction here is thought to be infrequent (Schäffer and Mammen 1999). In Bulgaria radio tracking showed that the two broods are produced in different locations, the second brood at a significantly higher altitude than the first one, thus benefiting from delayed vegetation development and later hay mowing at higher altitudes (Niemann 1995). It avoids very marshy areas, standing water, river and lake margins and open ground with rocks, stones and gravel (Del Hoyo et al. 1996), and also those areas with a thick layer of dead grass or very dense vegetation above 50cm tall (Cramp and Simmons 1980). Adults move to areas of high herbage along ditches to moult after breeding (Taylor and van Perlo 1998): embankments or fallow areas adjacent to the breeding habitat are very important as moulting sites (Taylor and van Perlo 1998). Non-breeding During migration it occurs in a variety of habitats including wheat fields and on golf courses (Taylor and van Perlo 1998). In the wintering grounds dry grassland and savanna are preferred with birds also occurring in rank grass near rivers, sewage ponds and pools and in relatively short grass in wetter areas, moist sedgebeds and reedbeds and in tall grass within young conifer plantations (Barnes 2000). It also occurs in Eragrostis hayfields, old land and pastures, maize fields bounded by grass, fallow and abandoned cultivation uncut grass on airfields, and the edges of sugarcane (Barnes 2000). It occurs where vegetation is between 30cm and 2m in height, and often in areas that are burnt during the dry season (Taylor and van Perlo 1998). Diet It feeds on a wide range of invertebrates, including taxa living on plants, on the soil surface and in the soil (Green et al. 1997). It takes a large number and wide variety of insects (Cramp and Simmons 1980), as well as snails and slugs, arachnids, millipedes, earthworms, young frogs, green parts of plants, young shoots and seeds and possibly even small mammals and birds (Cramp and Simmons 1980). Breeding site The nest is on the ground in dense vegetation and is constructed from dead stems and leaves (Green et al. 1997). Often surrounding stems are pulled over the top to form a loose canopy (Del Hoyo et al. 1996). The average clutch-size is c.10 eggs and two broods may be raised per season (Green et al. 1997).

This species breeds in Europe and central Asia, as far east as western China, and winters in sub-Saharan Africa. The European population was most recently estimated at 1,290,000-2,120,000 calling males or 2,590,000-4,240,000 mature individuals (including 1-1.5 million pairs in European Russia) (BirdLife International 2015), marginally higher than the previous estimate of 1.3-2 million pairs (BirdLife International 2004), which in turn was higher than the 1.1-1.8 million pairs in Europe previously estimated (Schäffer and Mammen 1999), and significantly higher than the 92,000-233,000 estimated in 1996, the difference resulting from the completion of the first systematic surveys of national populations in eastern Europe and Russia. A further 515,000-1,240,000 pairs are estimated for Asiatic Russia (Schäffer and Mammen 1999), yielding a global total of 3.6-6.7 million pairs or 5.4-10 million individuals. Given the high level of uncertainty in some of the breeding estimates and the apparent scarcity of the species in its non-breeding areas in sub-Saharan Africa, the total population may fall at the lower end of this range; even in the low millions. Whilst some of these populations may be increasing, population trends are unclear and often show large fluctuations (K. Koffijberg in litt. 2007) in response to changes in agricultural practices or annual rainfall (A. Mischenko in litt. 2006). Historically, most west European range states have seen major declines, which continued in some countries during 1990-2000 but were reversed elsewhere (BirdLife International 2004). The population in the UK recently increased, from 480 calling males in 1993 to 1,245 calling males in 2007, in response to conservation action (P. Walton in litt. 2006, K. Koffijberg in litt. 2007), although numbers dipped to 1,098 in 2009 (RSPB 2010) but were estimated at 1,200 calling males in the period 2006-2010 (BirdLife International 2015). Many western European states have observed a partial recovery since 1997, but dominated by large fluctuations (K. Koffijberg in litt. 2007). In Finland the population in 2003-2008 averaged around five times that in the 1990s (T. Lehtiniemi in litt. 2010). Monitoring since 2002 in 13 regions and republics in Russia (which holds the vast majority of the global population) indicates that numbers have remained stable or are even increasing (with some fluctuations due to extreme weather) (A. Mischenko in litt. 2010). Whilst it is difficult to accurately predict future trends owing to the species's extensive range, and differing climatic and agricultural conditions in different regions, it is thought that populations in key parts of the range in Russia and Kazakhstan are unlikely to change dramatically in the near future, although agricultural intensification and abandonment may drive some regional declines, and the species's conservation status in much of the western part of its range remains unfavourable.

Conservation Actions Underway
CMS (Bonn Convention) Appendix II. Bern Convention Appendix II. EU Birds Directive Annex I. The species is legally protected from hunting in most of the countries in its breeding range (Koffijberg and Schaffer 2006). Conservation measures have been taken in 14 European range states. National action plans have been prepared in Switzerland, Norway, the Netherlands, Czechia, Hungary, Germany, Denmark, UK, and Slovakia. Appropriate habitat management techniques have been researched, and local repeat surveys in Russia show relative stability of the population (A. Mischenko in litt. 2006). A European action plan was published in 1996 and a revised version published in 2006 (Koffijberg and Schaffer 2006), and a Corncrake Conservation Team was established in 1998. There is an ongoing reintroduction programme in England, UK (Newbery (2006).

Conservation Actions Proposed
Monitoring and research are needed into large-scale population dynamics, including estimating population trends, range shifts and changes in timing of breeding. Estimates of demographic rates and identification of key sites and threats faced by the species on migration are also required. Monitoring schemes should be implemented in range countries where knowledge of population size and trends is currently uncertain and the extent of land abandonment, particularly in Russia, should be monitored (BirdLife International Corncrake Conservation Team 2015). Monitor numbers through regular coordinated surveys, and improve monitoring in key countries (e.g. Russia, Belarus) (Doga Dernegi 2006, Koffijberg and Schaffer 2006). Monitor habitat condition and extent (Doga Dernegi 2006, Koffijberg and Schaffer 2006). Ensure that agri-environmental measures for the species in the EU are well targeted and implemented, and focus on mowing date and methods suitable for the species. Current uptake of agri-environment measures covers less than 25% of the respective national populations (BirdLife International Corncrake Conservation Team 2015). Agri-environment measures should be restored in Latvia and Slovakia and an adapted agri-environment menu is required in important breeding areas in Transylvania (Romania) to support conservation of Corncrakes and High Nature Value grasslands (BirdLife International Corncrake Conservation Team 2015). Increase the area of suitable habitat with protected status. Restore lost habitat where possible. Conduct further research into the species's ecology and demography (Koffijberg and Schaffer 2006). Work with farmers and land managers to ensure that traditional farming methods are retained, areas of grass are left uncut and harvest times are delayed (Doga Dernegi 2006). Monitor levels of illegal trapping and hunting (Koffijberg and Schaffer 2006). Lobby governments in remaining countries where it is not protected to afford the species legal protection (Koffijberg and Schaffer 2006).