This blog provides a summary of the GWCT's guidelines for conserving black grouse.
Introduction
The black grouse, a striking bird inhabiting the upland fringe, serves as a crucial indicator species, reflecting the ecological health of our moorlands and the transitional zones connecting forests and open landscapes.
Characterized by a unique communal breeding system and specific habitat needs, the black grouse population has faced significant declines over the past century. Therefore, collaborative and informed conservation efforts are essential to secure their survival and maintain the biodiversity of their habitat.
Understanding Black Grouse Ecology
Black grouse are birds of edge habitats, thriving particularly in the transition zones between northern forests and moorland heath. This specific habitat provides them with essential resources. They can find shelter in the forest during harsh winter weather. In the springtime, they feed on tree buds. During the summer, they nest on open ground and forage with their chicks among the grasses and heathland shrubs.
Lekking Behavior: Male black grouse, known as blackcocks, exhibit a spectacular communal breeding system. At dawn in the spring, they gather on traditional display grounds referred to as leks. Here, they stake out small patches of ground to entice females for mating. Good black grouse country will have lek sites on average every two kilometres.
Nesting and Brood-rearing: Female black grouse, called greyhens, are cryptically colored in mottle brown. They lay their eggs in thick ground vegetation within a kilometer or so of the lek. After the chicks hatch, the greyhens take their broods to feed among the tall grasses, rushes, and heathland shrubs, where the chicks initially feed on insects before transitioning to buds, flowers, and seeds. Most black grouse chicks hatch in mid-June and remain as a family covey until September. Young males tend to stay close to the home lek, whereas females often disperse several kilometers to other areas of suitable habitat with other black grouse populations.
Diet: Black grouse have a varied diet that includes heather and bilberry. They also consume buds, leaves, flowers, seeds, stems, and even the spore capsules of mosses, adapting their food choices to the seasons. In spring, black grouse favor cotton grass flower buds and larch buds. They also eat herbs like buttercup, sorrel, and marigold found in unimproved pastures and hay meadows. During the summer, black grouse prefer flowers, fruits, and seeds over leaves, consuming seeds of grasses, rushes, and sedges, as well as the flowers of herbs in wet bog flushes, herb-rich rough pastures, and hay meadows. Bilberry and cowberry fruits are eaten by adults, while young chicks initially require insects. In autumn, they consume berries of bilberry, cowberry, crowberry, and rowan, along with seeds of grasses and heath rush. After snowfall, black grouse move to the trees, feeding on the buds and catkins of birch and hazel, and the remaining berries.
Reasons for Decline
The black grouse population in Britain has experienced a significant decline since 150 years ago, when they were more numerous and widespread, even inhabiting many heaths of southern and eastern England. The decline and contraction of their range began about a century ago, following gradual improvements in farming.
The last estimate of black grouse numbers in Britain was 5,000 displaying males in 2005, with the population centered on a few key upland areas of Scotland, northern England, and Wales. Most worryingly, in the late 1990s, the black grouse population was declining at a rate of approximately 8-10% per year, accompanied by a continuing contraction of their geographical range. Factors contributing to this decline include:
Loss of Habitat Mosaic: Land use used to be mixed. Black grouse favor a patchwork quilt of farmland adjacent to moor and forest, and they need a sweep of suitable countryside to sustain their population. Contiguous areas have been broken up by block forestry and intensive farming.
Over-grazing: High densities of sheep and red deer consume ground cover, reducing the abundance of caterpillars needed by grouse chicks. Heavy grazing, especially along the lower edge of the moor, erodes the heather line and produces a short turf lacking the cover and food of tall grasses and herbs.
Changes in Forestry: Black grouse prefer the ground cover in young plantations, but they tend to leave as these develop into solid conifer thickets. Forest edges used to transition into heathland through scattered trees, but today’s forests have hard edges. The early stages of a plantation are ideal for black grouse as the native heath flourishes in the absence of grazing stock. By the thicket stage the grouse are gone and fence lines increase mortality.
Increased Mortality: Higher populations of predators such as crows, foxes, and stoats, as well as some birds of prey, cause high annual losses. In addition, forest deer fences kill many birds.
Other factors: Releasing hand-reared pheasants or redleg partridges along the moorland fringe could displace black grouse.
Key Conservation Measures
To reverse the decline and promote the recovery of black grouse populations, several conservation measures can be implemented, focusing on habitat restoration, predator control, mortality reduction, and sustainable shooting practices:
Habitat Restoration
Create Habitat Mosaics: Encourage a diverse patchwork of farmland, moor, and forest to provide varied habitats that meet the seasonal needs of black grouse.
Reduce Over-grazing: Implement grazing management strategies to maintain adequate ground cover and ensure the availability of essential food plants for black grouse chicks. Reducing grazing pressure improves breeding success.
Improve Forestry Practices: Design forest edges to be feathered, incorporating native trees and shrubs to create a gradual transition between forest and moorland. Dissect plantations with wide breaks to encourage shrub growth and enhance habitat diversity. Forestry plantations should have feathered edges where they abut moorland. Berried shrubs, and trees like birch, willow and rowan should be encouraged. Plantations themselves should be dissected with wide breaks in which shrubs can be encouraged. New transition zones can be created along sheltered burns and gills by allowing larger shrubs and dwarf birch to develop.
Manage Moor Edge Allotments: Promote diverse swards of heather, bilberry, rush, and grasses in moor edge allotments to provide varied foraging and nesting opportunities. Moor edge allotments should be managed to create a diverse sward of heather, bilberry, rush and grasses.
Retain Bogs and Rushy Pastures: Preserve wet areas and unimproved hay meadows, as they are vital habitats for black grouse, providing essential food sources and cover. Bogs are ecological assets on any moor and should be retained as should in-bye rushy pastures. In-bye fields along the lower moor edge need special attention. Wet rushy fields and unimproved hay meadows are important. Pastures should not be heavily stocked and some small arable plots can be used by black grouse.
Predator Control
Implement Systematic Predator Control: Manage populations of predators such as foxes, stoats, and crows, particularly during the breeding season, to reduce predation pressure on black grouse. Losses to predators are most serious during the breeding season. Where there is an existing game shooting interest, as on a grouse moor, black grouse survival will improve if the gamekeeper undertakes a systematic predator control programme for red grouse. Where a professional gamekeeper is not operating, predator control is much more problematic. A half hearted approach to predator control is usually a waste of time and most effort should go into habitat improvement.
Enhance Habitat: Create native woodlands to provide escape cover from predators, improving grouse survival rates.
Reduce Mortality
Mark Deer Fences: Mark deer fences to prevent collisions, reducing mortality among black grouse populations.
Improve Nutrition
Enhance Hen Nutrition: Ensure the availability of protein- and energy-rich foods before egg-laying, such as herbs, cotton grass, and buds, to improve hen health and breeding success. In the weeks before egg-laying, greyhens need food rich in protein and energy. They also need to lay down fat for incubation. Herbs from in-bye fields, flowering cotton grass, and the buds of larch, birch and willow should be available.
Promote Insect Abundance: Restrict grazing to improve insect populations, providing an essential food source for black grouse chicks. Young chicks foraging with the hen need to consume insects at a rapid rate. Caterpillars and sawfly larvae are important foods as are ants in pine forest fringe habitats in Scotland. Experiments show that restricting grazing may be the key to improving insect abundance in some areas.
Sustainable Shooting Practices
Adhere to the Shooting Code: Ensure that shooting practices are sustainable and do not negatively impact black grouse populations. Black grouse are legal quarry and may be shot in season (20 August to 10 December). But sustainable shooting is possible only where productivity is high.
Shoot only when populations are high: Shooting should only occur if spring counts show that leks have more than 15 males each year, and that overall, there are two cocks for every 100 hectares of suitable habitat. Also, August counts with dogs should indicate more than three young per hen at the end of summer, taking an average of at least 10 broods. Surveys on neighboring ground should show similar good numbers of birds.
Avoid shooting greyhens: Focus exclusively on shooting cocks to protect the breeding female population.
Limit the percentage of cock birds shot: Never harvest more than 15% of the spring stock of cock birds.
Monitor Populations: Conduct regular spring and autumn counts to assess population health and adjust management practices accordingly.
Implement Predation Control and Habitat Improvement: Ensure that a program of predation control and habitat improvement is in place.
Re-introductions and Translocation
Translocation Trials: Consider translocation trials to move cocks to the southern fringe of their range, establishing new leks and attracting dispersing hens to expand the species' range. The translocation trial, which aimed to deliver range expansion, was a success with released cocks lekking and attracting hens, that subsequently bred successfully. Black grouse cocks were caught at night and transported directly to the release areas where they were released immediately.
Success Stories: The North Pennines Black Grouse Recovery Project
The North Pennines Black Grouse Recovery Project (1996-2010) provides a compelling example of the effectiveness of targeted conservation efforts. By restoring moorland fringe habitats through reductions in sheep grazing, black grouse breeding success significantly improved, resulting in a 5% annual increase in displaying males.
Numbers recovered from 773 cocks in 1998 to an estimated 1,200 in 2007, surpassing the BAP target of 1,000 cocks by 2010 ahead of schedule. A translocation trial further aimed to expand the species' range, yielding encouraging results as released cocks attracted hens and bred successfully.
Conclusion
Conserving the black grouse demands a concerted and collaborative effort from landowners, gamekeepers, conservationists, and the wider public. By implementing the measures outlined above, we can collectively contribute to restoring black grouse populations and enhancing the biodiversity of our moorlands.