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Crex Crex - The Corncrake

Callows
The Callows are a feature of the Shannon, Little Brosna and many other river systems in Ireland. They represent an important part of the wetland mosaic of Ireland. These areas, with their rich vegetation, occur adjacent to many important raised bogs, rivers, lakes and fen habitats. The decline of the callows and their more intensive use in agriculture, and the moves to have them conserved, has mirrored the history of many other Irish wetland types, most importantly the Midland raised bogs.

The campaign to protect the callows has been closely linked to the protection of one particular species - the Corncrake. Study of the dramatic decline of this species, its near extinction, and its more recent recovery and even re-introduction to new or formerly abandoned areas makes an excellent example of how man can and has influenced his environment. Study of the conservation measures applied to corncrakes together with more environmentally conscious farming activities show how these can work together to improve the survival opportunities for a rare and threatened species.

A Study of the Callows will help us understand how mechanisation and changes in agricultural and economic practices, have had a major impact on other Irish habitats, including raised bogs, uplands and hedgerows.

What a Crecker!
The corncrake (Crex crex) belongs to the Rallidae family of birds which also includes moorhens, coots and water rails. Corncrakes have a mottled buff brown plumage, a speckled grey head and neck, with black streaks on their back. It is only in flight that the bright chestnut patches on their wings catch the eye. They have short stumpy tails and trail their legs while in flight. Both sexes look almost identical with the male having less grey in the plumage. Corncrakes stand about 10 inches tall. Unlike their aquatic relatives they are very secretive birds that skulk in the cover of grass or tall herb vegetation rarely straying out into the open. The harsh but distinctive "crek crek" call of the male during the mating season is probably the closest most of us will ever come to encountering one of these elusive birds which has become one of the most endangered species in the country.

Corncrake Life Cycle
In the second half of April the corncrakes arrive in Ireland from their wintering grounds in south-eastern Africa, e.g. Zambia, Mozambique, Tanzania and Madagascar looking for a suitable place in which to breed, a distance of 10,000km. They seek out long grass in which to hide and call for a mate before choosing the nest site. When the males arrive they announce their presence and attract a mate with the well known crek crek song. This was once a very familiar night time sound (their main vocal time is between midnight and 3 a.m.) in rural Ireland.

Once a nest has been built mating occurs and the females start to lay their first brood in late May. The first clutch contains about 12 eggs with later clutches containing 10 eggs or less. The nest is a grass lined scrape or a swirl of grass on the ground located in areas of tall vegetation, usually in hay or silage fields. This ensures continuous cover to the birds and a good food supply for the chicks. The incubation period lasts about 16-18 days with peak hatching dates in mid-June. The females care for their black chicks for the first 12 days. The chicks can run very quickly and find food for themselves. After approximately five weeks the chicks fledge. There is virtually no delay between the completion of rearing of the first brood and the commencement of egg laying of the second clutch. Furthermore there is only an interval of about 40 days between the hatching dates of the two broods. Peak hatching dates for the second brood are in late July. In general males appear to take no part in rearing young, and move around during the season in the hope of attracting more females (Stowe and Hudson 1991). Calling males are usually heard most often in the middle of the night. By day they move quite widely, feeding on, among other things slugs, weevils and seeds. In August the birds moult so that they have new feathers for migration. From the beginning of September both adults and young take flight from Ireland, back for another winter in south-eastern Africa.

Breeding Habitat
Relatively few bird species are adapted to nesting in open farmland. The corncrake however is one such species. The most important habitat component for corncrakes are hay-meadows. When the corncrakes arrive in Ireland in late Spring they make much use of tall marsh vegetation containing Yellow Flag Iris (Iris pseudacorus), Reeds (Phragmites australis) and Reed Grass (Phalaris arundinacea) when the grass in the meadows is still too short to give them adequate cover.

Traditional corncrake breeding grounds are tall grass meadows (callows) or other tall grasses but some nest in silage fields, rough pasture and less frequently in marshes, peat bogs, gardens, cereal and rootcrops (Mayes and Stowe 1989). However in some areas hay-meadows have been replaced by sheep pasture, in which the grass is too short for corncrakes, and in other areas abandonment of hay making has led to the spread of rushes (Juncus species) which are tall plants but are too closely spaced to be used by the corncrake. Unmowed vegetation along ditches, mosaics of small meadows mowed at different times, and strips of meadows left unmown are also important in providing refuges for corncrakes during and after mowing of the hay meadows.

Corncrakes nest on the ground close to the centre of the meadow and the tall vegetation provides cover and protection from predators whilst feeding and breeding. The soils of these meadows are overflowing with insects, bugs and worms providing a feast on which the corncrakes can feed themselves and their young. The wetter and softer the soil the easier it is for the adult corncrake to dig deep into the soil to reach their food.

Callows
Callows are important refuges for corncrakes. The word Callow is derived from the Irish word caladh, which describes a seasonally flooded grassland. Grasslands of this type are found along the banks of rivers and traditionally were used as hay meadows by farmers. The rivers flood during the spring and winter depositing silt and nutrients on the surrounding fields which support a variety of wildlife (Dwyer 1997).

A number of habitats can be found on the callows which support a diverse range of vegetation. Nearest to the river the grasslands are rich from silt deposits and waterlogged for most, if not all of the year. As the distance from the river increases the grasslands become drier during the summer months. The vegetation is adapted to these wet conditions and, typically includes water forget-me-not (Myosotis scorpioides), marsh marigold (Caltha palustris), yellow loosestrife (Lysimachia vulgaris), ragged robin (Lychnis flos-cuculi) and grasses including meadow fescue (Festuca pratensis), rough and smooth meadow grass (Poa trivialis and Poa pratensis) and tufted hair grass (Deschampsia cespitosa).

Drier soils are found further away from the river. These occur on a higher level on old river soil deposits. This habitat is home to a number of grasses including the cock's foot (Dactylis glomerata), false oat grass (Arrhenatherum elatius), timothy (Phleum pratense) and crested dog's tail (Cynosurus cristatus); as well as adder's tongue fern (Ophioglossum vulgatum), the common spotted orchid (Dactylorhiza maculata) and the green twayblade (Listera ovata).

Callows are particularly important for birds. The saturated soils in the spring make ideal feeding conditions for waders. The wet ground conditions delay the cutting of the grass, and provides time and space for ground nesting birds such as the corncrake to complete their breeding cycles. In October the river floods the fields forming a shallow elongated lake. This creates an important wintering ground to many birds such as the whooper swan, greenland white-fronted geese, golden plover, lapwing and curlew.

Corncrake Distribution
Originally corncrakes bred over much of northern and central Europe in a band between 440 and 630 North, extending to Siberia 1200 East. Nowadays the distribution is much restricted and fragmented (Batten et al 1990). Although they are weak flyers on the breeding grounds, corncrakes are among the most accomplished travellers flying some 10,000 km from the breeding grounds in temperate Europe and Siberia to over winter in south-eastern Africa.

Corncrakes that breed in western Europe travel south into Africa via Egypt. In 1990 it was estimated that there was a western European population of between 5,000-7,500 calling males, with several thousand in eastern Europe (Hudson et al 1990). In 1993 there were 7,000 calling males in Poland and 489 in the UK. In 1991-1992 there were 1,100-1,200 calling males in France. Distribution numbers in the former Soviet Union are unclear however it is known that distribution and numbers have declined in the Baltic states whereas the corncrake is still quite widespread and common further east.

Corncrake Population Decline in Ireland
Two centuries ago corncrakes were described as being common, breeding in every field in Ireland. The population at the turn of the century was estimated to be in the tens of thousands. By the 1940's declines had been recognised in most areas and the population was only thought to be stable in the North West. The Corncrake was still widespread in every Irish county at the beginning of the 1970's, (being reported from 83% of Irish 10 km squares during the 1968-1972 BTO/IWC survey for the Atlas of Breeding Birds, Sharrock 1976). However the geographical range of the Corncrake had declined markedly during the 70's leaving populations largely restricted to Ulster and Connacht with a few pockets of distribution still remaining in Munster and Leinster.

One Irish survey completed by BirdWatch Ireland in 1978 which coincided with a similar survey conducted in Britain in 1978-79 concluded that the geographical range of the corncrake had declined noticeably during the 1970's. Gaps that had existed in the south and east had joined up, leaving the distribution of the corncrake largely restricted to Ulster and Connacht. Munster and Leinster only contained a few small pockets of distribution. The 1978 survey revealed that the population had declined to about 1,000-1,200 pairs concentrated west of the river Shannon.

Joint surveys in 1988 carried out by BirdWatch Ireland and RSPB in Ireland (Mayes and Stowe 1989) and the RSPB in Britain (Hudson et al 1990) found that although there were areas where the bird could be found in strength, further declines were definitely apparent. The survey revealed that the total count of calling birds for all of Ireland was 903-930, with 781-797 in the Republic and 122-143 in Northern Ireland. From the map below it can be seen that in 1988 there were only five areas in which corncrakes were relatively common.

Only 310-320 calling birds were identified along the northern coastline of Donegal but with smaller numbers overall along the Foyle and Swilly catchments. The Moy river catchment in Mayo and west Sligo recorded fairly good numbers as did the western seaboard, including the Mullet Peninsula, and the islands of Inishturk and Inishbofin. The Shannon Callows between Athlone and Portumna recorded 125 birds, with virtually all of them calling from the large hay meadows on the Callows. In Northern Ireland the corncrake population was centred around Lough Erne. The 1988 survey showed a decline of 30% from the previous survey in 1978. Even in 1988 it was clear from the findings that the distribution of corncrakes had changed, with very few birds in counties Galway and Clare, for example, and fewer in the eastern part of Northern Ireland. As expected most birds were recorded in meadows.

The New Atlas of Breeding Birds in Britain and Ireland 1988-1991 showed a further reduction of 70% in the range of the corncrake since the 1968-72 survey (Gibbons et al 1993).

The 1993 BirdWatch Ireland/RSPB Corncrake Census recorded 174 singing male corncrakes in Ireland, a decline of over 80% since the previous survey in 1988. The remaining population was found to be concentrated in four main areas: the Moy valley in Co. Mayo, the Shannon callows in the midlands, North Donegal and the Erne catchment in Fermanagh.

129 calling males were recorded in 1994, a decrease of 25% on the previous years numbers. This decrease was due mainly to the flooding that occurred in June 1993 on the Shannon Callows. In 1995 the Corncrake population in Ireland increased for the first time since recording began. Numbers rose by almost 35% to 174 calling males, with the greatest increase in Donegal, particularly on the islands of Inishbofin and Tory. This increase continued in 1996, when 184 calling males were recorded.

Declines in Corncrake numbers have been reported from most parts of the world. It is the only Irish bird species listed as "rare" on a world-wide scale in the International Union for the Conservation of Nature's Red List of Threatened Animals.

Corncrakes and Farming
Viewed from the air the Irish countryside is a tapestry of colours resembling a patchwork quilt. On the ground it is composed of smells, sounds and a rich community of plants and animals. Traditional farming practices particularly grassland farming have created a wonderfully rich, aesthetically pleasing land that is of immense importance to wildlife. They are virtual jungles abundant in insect life, wild flowers and berries which can support large numbers of species.

Traditional farming practices pre-1940's
Grassland farming has been the most important factor in shaping the rural economy of Ireland for the last 6,000 years. Some 11 million of the 17 million acres land area of Ireland is covered by some type of grassland. The corncrake is one of the few birds adapted to nesting in open farmland. Traditionally they have been associated with old style hay-making and were once a common feature of meadows throughout the country, their nests remaining undisturbed in the long grass during the crucial breeding season.

The introduction of the scythe, which is thought to have been brought to Ireland by the Normans, created a new farming practice commonly known as hay-making. Traditional hay-making was the physical cutting of tall grasses with a scythe to produce winter fodder. This practice although it would have disturbed the corncrake to a certain extent did not pose any significant threat to its life or that of its young. The movement of the farmer through the field, scythe in hand, alerted the corncrake to his presence and the possible dangers that this could entail thus giving the bird plenty of time to escape and giving the farmer the opportunity to avoid killing the bird, its eggs or chicks. This kind of farming practice allowed the farmer and the corncrake to exist side by side without interference or disturbance.

From the middle of the 20th century cattle numbers rose steadily creating a growing demand for hay to be made for winter fodder. This caused problems for the corncrake as meadows changed to hay-making factories. The replacement of the hand-scything of hay by mowing with horse drawn machines has been the most important factor initiating the decline in corncrakes prior to 1940 (Norris 1947).

Modern Farming Practices
The 1960's saw increased farm mechanisation, with horse drawn mowing machines being replaced with tractor drawn mowing machines and silage trailers. The corncrake, perhaps more than any other bird species, suffered when traditionally managed meadows began to be replaced with modern agricultural methods. The decline of the corncrake coincided with the period when the majority of hay-meadows in various areas began to be cut using mowing machines.

In 1992 the collapse of financial subsidies for beef cattle farming led farmers to switch to sheep farming. Farmers managed the land differently. Hay meadows filled with tall grasses were replaced by short pasture land. More recently with the BSE ("mad cow" disease) scares that have hit farmers the length and breath of the country there has been a notable decrease in beef cow production. No cattle means no hay, no hay means no corncrake causing the potential extinction of an already rare, but once very common bird.

The switch from hay-making to silage making also had an important influence on the survival of the corncrake and this change in practice is a direct result of increased mechanisation. Wet summers in 1985 and 1986 resulted in some serious hay loss and therefore saw many western dairy farmers change over to silage making on a permanent basis. Silage production involves more than one crop per year with the first crop being taken before the meadow plants can flower. Corncrakes need vegetation taller than 20 cm, that is not too dense or matted for nesting and moving about in.

A shortage of tall vegetation also occurs in late summer after mowing. However along the shores of Lough Erne and in the Shannon Callows farming intensity is generally low with minimum use of fertilisers. This results in late maturing of hay crops and harvesting is later compared with surrounding land giving the corncrake a chance to raise their young to a stage of flight.

In general mowing takes place from mid June onwards. As a result second nests and both first and second broods are at risk of being destroyed. Many adults and chicks are killed during mowing when machines work from the periphery of the field inwards. Reluctant to run out into the open and across the part of the field that has been mowed the birds become trapped in the middle of the field and have little chance of escape.

Other secondary reasons for the decline of the corncrake, include the introduction of herbicide/chemical fertilisers which encourage the vigorous growth of agricultural grasses, while chemicals poison the soil and its inhabitants and therefore the only source of food available to the corncrake.

This method of cutting from the outside to the centre of the meadow, leaves nowhere for the secretive corncrake to hide from the machines. It is not corncrake-friendly.

Cutting the field from the middle outward is corncrake-friendly.

Cutting the field in strips from side to side.

Cutting from the gate towards the centre and out towards the edge.

Three Corncrake-friendly mowing methods These give corncrakes a chance to escape from the meadows to safety in overgrown drains, hedges or reeds at the river edge (adapted from Heery 1993)

Incentives for Farmers
In order to increase corncrake breeding success, BirdWatch Ireland, with the support of Dúchas of the Department of Arts, Heritage, Gaeltacht and the Islands and the Royal Society for the Protection of Birds, has operated a corncrake Conservation Programme in Ireland since 1991. BirdWatch field workers in each of the core corncrake areas count singing male corncrakes and advise farmers on "corncrake friendly" farming methods. Farmers with corncrakes in their meadows are eligible for entry to the Corncrake Grant Scheme. Grants are payable to those who delay mowing of hay or silage until the 1st August, by which time most corncrakes should have hatched two broods. Research has shown that in order to maintain population levels, corncrakes need to hatch two broods. So far, 25 Fermanagh farmers have signed up while many others have made enquiries.

There is also a grant for mowing from the centre of the field outward, which gives young corncrakes a chance to run towards the edges, to safety, under cover of the remaining grass. This is an unconventional more time consuming way of farming, nevertheless, many farmers on the Shannon Callows demonstrated their concern in 1992 by attempting this corncrake friendly practice.

There is often a shortage of cover available for corncrakes when they arrive in Ireland in Spring. Nettles and Iris patches provide suitable early cover and BirdWatch Ireland has been working with farmers encouraging them to increase the area of such cover. Cover may also be limited at the end of the season, after most of the hay has been cut. This is a particular problem in the Shannon Callows and some farmers in this area are offered a further grant payment to delay mowing further, until 1 September, in order to provide cover for corncrakes through the month of August.

In the future consideration will be given to expanding and refining Corncrake Conservation Schemes in the Republic and Northern Ireland, increasing state compensation payments to farmers, including more corncrake breeding areas within Environmentally Sensitive Areas and Special Protection Areas and defining management prescriptions for the conservation of corncrakes under the Rural Environment Protection Scheme. The RSPB is also promoting a 'hay premium scheme' through the Common Agricultural Policy, to pay farmers to grow hay, not silage, with a later harvesting date, reducing risks to corncrakes (Williams et al 1997).

Ultimately if these schemes are successfully run they could help to prevent one of our best loved birds from becoming extinct. But even if farmers are making silage, they can take steps to ensure that corncrakes are given a good chance to breed in safety. Leaving areas of rough vegetation on the farm uncut during spring and summer will also help.

A new corncrake census has confirmed that the project is being successful in protecting the corncrake in the areas covered by the grant scheme. It is doubtful if they would succeed however, without the goodwill of farmers and the advice and encouragement of the corncrake field workers. Factors contributing to the increase include an 80% uptake of grants in the Callows as opposed to 60% in the north-western areas and the fact that a substantial area of the mid- Shannon flood plains is not suitable for the level of agricultural intensification that has taken place elsewhere.

Can the Corncrakes be Saved?
Corncrakes have declined throughout western Europe, but in areas where conservation projects have been initiated, e.g. Scotland and Ireland, there have been increases in recent years. In Eastern Europe and Russia there are still large numbers of corncrakes. However, populations in these areas are also threatened, as political changes may lead to rapid intensification in agriculture.

The Corncrake is the only Irish breeding bird that is threatened with global extinction. Following decades of decline, the trend is changing and increases in corncrake numbers were recorded in 1995 and 1996. A series of conservation measures have been put in place in an effort to halt the decline in the numbers of birds and to increase the numbers if possible. These measures must be kept up to ensure that the positive trend seen in recent years is maintained.

The link between land use and the birds is direct and simple. Corncrakes need hay fields. Silage will not do.

Radio-tracking studies showed that corncrakes need vegetation taller than about 20 cm to survive, if it is taller than this they can find it difficult to walk through. Populations tended to decline in regions where tall marsh vegetation and hay meadows decreased and short pasture grazed by sheep increased.

There can also be a shortage of tall vegetation in late summer after mowing. This problem is most common in the Shannon Callows in Ireland where mowing and grazing remove most of the available cover. In such areas patches of unmowed vegetation along ditches and small meadows left unmown are important in providing refuges for corncrakes during and after mowing.

Where the average mowing date was in early July the number of chicks raised was half of that where the mowing date was in mid August. Corncrake populations were relatively stable in most areas where the average mowing date was in August, but they were declining where mowing was earlier.

Observations of chicks during mowing showed that many were killed when mowing machines worked from the periphery of the field inwards. Chicks are reluctant to run along the part of the field that has been mowed and become trapped in the section remaining to be mowed. Moving from the centre of the meadow outward allows chicks to run into vegetation outside the meadow without leaving the cover of tall vegetation. Starting cutting along one side of the field only, reversing or turning round to cut the next strip, again herds any birds present towards the field edge and away from danger.

Mowing from the centre of the meadow outward reduces mortality of chicks per mowing episode from about 40% to about 10%. This is probably an under-estimate of the effect of the change in mowing method because chicks are more likely to escape from the meadow during Corncrake friendly mowing without being recorded. It is estimated that the productivity of Corncrakes would be increased by about 20% by switching from outside-inwards to Corncrake friendly mowing if the average mowing date is in early July and by 10% if it is in August.

Radio-tracking of pairs revealed that all nests were within 160 m of the calling place of the male and brood-rearing areas were within 200-300m. Hence conservation actions during mowing would be effective if applied near to calling places of males.

In Scotland and Ireland Corncrakes only persist in areas where stands of vegetation tall enough to provide cover in spring and late summer occur adjacent to hay meadows, and where the mean date of mowing is in late July or August. Areas with ample tall vegetation, but where mowing is early and those where mowing is late but there is little cover are not suitable for corncrakes. Conservation measures to increase the area of suitable vegetation and change the timing and method of mowing must be introduced together if they are to be effective.

The public in areas where the Corncrake still breeds are enthusiastic in assisting in it's survival. The local media are always interested to hear how the season is progressing and local people report Corncrakes they hear to Birdwatch Ireland field workers. This support is vital to the continued success of the project and allows anyone with an interest to support the campaign.

Corncrakes are protected by the Wildlife Act (1976) which means that it is illegal to disturb them in any way.

Further Reading

Batten, L. A., Bibby, C. J., Clement, P., Elliott, G. D. and Porter, R. F. (1990) Red Data Birds in Britain. T. and A. D. Poyser, London.
Casey, C. (1995) Corncrake Shuffle. IWC News 85: 7
Casey, C. (1997) BirdWatch Ireland's Corncrake Conservation Project. Information Leaflet
Casey, C. (1995) Corncrake breakthrough ..... but shock news. IWC News 84: 7
Casey, C. (1997) Corncrakes Survive Wet Summer. Wings 7: 13
Coveney, J. (1995) Corncrake Programme is strengthened. IWC News 82: 7
Coveney, J (1994) More help for corncrakes. IWC News 79: 9.
Coveney, J. (1993) Corncrake Population in Tailspin. IWC News 77: 7
Coveney, J. (1993) The Corncrake Sherkin Comment. Issue No.13: 19
Derwin, J. (1997) Corncrake Fieldwork in North Donegal 1997. Birdwatch Ireland Conservation Report No.97/7
Dwyer, R. (1997) Our Grassland Heritage - A case for conservation. Irish Wildlife Trust, Dublin.
Gibbons, D. W., Reid, J. B. and Chapman, R. A. (eds) (1993) The New Atlas of Breeding Birds in Britain and Ireland: 1988-1991. T. and A. D. Poyser, London.
Haines, J. (1991) 1991: The Year of the Corncrake. IWC News 66: 3
Heery, S. (1993) The Shannon Floodlands. A Natural History Tír Eolas, Galway.
Hudson, A. V., Stowe, T. J. and Aspinall, S. J. (1990) Status and distribution of Corncrakes in Britain in 1988. British Birds 83: 173-187.
Hunt, J. (1997) Stable or Critical ? Corncrakes are in trouble. Wings 6: 12
Mac Connell, S. (1997) Saving the Corncrake at the expense of hay. Irish Times : August 13th
Mac Lochlainn, C. (1993) Rescue package for the corncrake. IWC News 75: 5
Madden, P. (1996) Go Wild at School. School Wildlife Garden Association, Dublin
Mayes, E. (1988) Save the corncrake. IWC News 55: 6
Mayes, E. (1989) Corncrakes in Ireland Results of the 1989 Survey. IWC News 59: 7
Mayes and Stowe (1989), The status and distribution of the Corncrake in Ireland, 1988. Irish Birds 4: 1-12
Mc Garry, P. (1996) Corncrake numbers grow for second year. Irish Times: July 23
Murphy, J. (1994) Glimmer of hope for corncrakes. IWC News 80: 7
Nairn, R. (1989) Hay Meadows. IWC News 59: 6-7
Norris, C. A. (1947) Summary of a report on the distribution and status of the corncrake (Crex crex). British Birds 38: 142-148, 162-168.
O'Faolain, N. (1997) Crake Expectations. Irish Times: July 30
O'Meara, M. (no date) Where have all the corncrakes gone? In The Irish Wildlife Book edited by Fergus O'Gorman, pages 61-64.
O'Meara, M. (1979) Distribution and numbers of corncrakes in Ireland in 1978. Irish Birds 1: 381-405
Sharrock, J. T. R. (1976) The Atlas of Breeding Birds in Britain and Ireland. T. and A. D. Poyser, London.
Sheppard, R. and Green, R. E. (1994) Status of the Corncrake in Britain and Ireland in 1993. Irish Birds 5: 125-138
Stowe, T. J. and Hudson, A. V. (1991) Radio-telemetry studies of Corncrakes in Great Britain. Die Vogelwelte 112: 10-16
Whilde, A. (1993) Threatened Mammals, Birds, Amphibians and Fish in Ireland. HMSO, Belfast.
Williams, G., Green, R., Casey, C., Deceuninck and Stowe, T., (1997) Halting declines in globally threatened species; the case of the corncrake. RSPB Conservation Review 11: 22-31

Further Information

BirdWatch Ireland - IWC, Ruttledge House, 8 Longford Place, Monkstown, Co. Dublin. Tel. 01 2804322, e-mail: by clicking here Visit their web site by clicking here - http://www.birdwatchireland.ie/

Dr Catherine O'Connell