Justification of Red List Category
This species has an extremely large range, and hence does not approach the thresholds for Vulnerable under the range size criterion (Extent of Occurrence <20,000 km2 combined with a declining or fluctuating range size, habitat extent/quality, or population size and a small number of locations or severe fragmentation). Despite the fact that the population trend appears to be decreasing, the decline is not believed to be sufficiently rapid to approach the thresholds for Vulnerable under the population trend criterion (>30% decline over ten years or three generations). The population size is extremely large, and hence does not approach the thresholds for Vulnerable under the population size criterion (<10,000 mature individuals with a continuing decline estimated to be >10% in ten years or three generations, or with a specified population structure). For these reasons the species is evaluated as Least Concern.
In Europe, the breeding population is estimated to number c.1,480,000-2,920,000 pairs, which equates to 2,950,000-5,830,000 mature individuals (BirdLife International 2015). Europe forms approximately 30% of the global range, so a very preliminary estimate of the global population size is c. 9,800,000-19,400,000 mature individuals although further validation of this estimate is needed. The population is therefore placed in the band 9,000,000-19,999,999 mature individuals. In addition, national population estimates include: c.10,000-100,000 breeding pairs in China; c.100-10,000 breeding pairs in Korea; c.100-10,000 breeding pairs in Japan and c.100,000-1 million breeding pairs in Russia (Brazil 2009).
The population is suspected to be declining owing to habitat destruction (del Hoyo et al. 1994). Local extinctions have been recorded in parts of China and Mongolia as a result of forest loss (Madge and McGowan 2002). Within the species's European range the population is estimated to be stable (BirdLife International 2015, EBCC 2015).
The following information refers to the species's habitat use within Europe. The species is found in mixed coniferous deciduous woodland, both in plains and mountains. It seems to avoid pure coniferous stands and occurs in areas without conifers (de Juana and Kirwan 2013). It generally prefers large, dense forests with rich, varied undergrowth (up to c. 2 m tall) and occasional clearings (Madge and McGowan 2002). Laying occurs in April and May in central Europe and May to June in Scandinavia (de Juana and Kirwan 2013). It lays seven to eleven eggs. The nest is a shallow scrape lined with plant material and well concealed by undergrowth or under roots of fallen trees (Madge and McGowan 2002). Its diet changes seasonally, feeding on catkins, buds and twigs of Alnus and Betula in winter; leaves, flowers and newly sprouted vegetation in spring (Swenson 1994); berries and fruits in summer and autumn; and nuts, acorns and seeds in autumn. Chicks feed almost exclusively on arthropods during the first ten days before becoming more vegetarian. The species is highly sedentary (de Juana and Kirwan 2013).
The species has very specific habitat structure requirements (Madge and McGowan 2002) and so is very sensitive to habitat changes, particularly modern forestry trends (Schäublin and Bollmann 2011, de Juana and Kirwan 2013). Although small-scale timber work could have positive effects, as could permitting natural reforestation of areas subject to natural events such as avalanches, insect calamities, fires and erosion. The species is hunted but it has secretive habits and it is unlikely to be significantly affected by this, although in the 1970s some annual bag totals reached c. 10,200 birds in Norway, c. 18,000 in Sweden and 28,000-69,600 in Finland. It is more intensively hunted in European Russia and Siberia where perhaps as many as two million birds were taken per annum during the early 1990s (de Juana and Kirwan 2013). In countries where harvesting is important, e.g. Finland it is often easier promoting management practices that favour the species. The species has an enormous range, so protected areas play only a very limited role in its protection, although conservations units can be locally important in the preservation of subpopulations, e.g. in Greece, Hungary and Belgium) (de Juana and Kirwan 2013).
Conservation Actions Underway
EU Birds Directive Annex I and II. Reintroductions have been attempted in some areas such as west Germany (de Juana and Kirwan 2013). Hunting of this species is banned in several European countries. A small proportion of its European range is covered by protected areas. Monitoring is common in Fennoscandia for the purpose of harvest planning. Elsewhere in Europe, monitoring and surveys are mostly regionally restricted and irregular. In some parts of Europe habitat management, such as maintaining coppice woodlands, favouring deciduous trees and shrubs within coniferous forests and planting patches of conifers for cover within extensive deciduous forests does occur (Storch 2007).
Conservation Actions Proposed
Forest practices should be integrated with habitat conservation and habitats for the species need to be considered at a landscape scale, maintaining and restoring spatial connectivity among populations. In countries on the edge of its range, protected areas may be effective in preventing declines as well. Monitoring of populations should be undertaken to ensure numbers are stable and exploitation is sustainable. Better law enforcement is needed in countries where it is threatened and illegal hunting is common (e.g. Bulgaria and Greece) (Storch 2007).
Text account compilers
Ashpole, J, Butchart, S., Ekstrom, J.
BirdLife International (2021) Species factsheet: Bonasa bonasia. Downloaded from http://www.birdlife.org on 23/10/2021. Recommended citation for factsheets for more than one species: BirdLife International (2021) IUCN Red List for birds. Downloaded from http://www.birdlife.org on 23/10/2021.