Statut of the Coot in Europe
Abstract
Status of the Coot in Europe
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Social organization and home ranges of the hybrid partridge (Alectoris graeca saxatilis x Alectoris rufa rufa): seasonal and individual variations. Gibier Faune Sauvage, Vol. 8, mars: 1-30.
Seasonal and individual changes in the social organization and home range sizes of natural hybrids between Rock partridge ( Alectoris graeca saxatilis) and Red-legged partridge (Alectoris rufa rufa) were studied in the Southern French Alps by following 40 birds equipped with radio tags for periods varying between two months and two years, between September 1984 and May 1989. The partridges' social behaviour changes throughout the annual cycle. They are predominantly living in groups from late summer, soon after breeding, to early spring when groups will disperse. Between September and March, mean group size is 4.5 individuals. The partridges' tendency to gregariousness is apparently at its highest in winter when 90% of them are living in groups. From September to December, females are more gregarious than males. Groups may be composed of juveniles and adults, and of birds of both sexes. Family groups form fairly stable units contrary to groups made up of nonincubating or unsucessful nesting birds.
Partridges have a tendency to separate themselves from their wintering group prior to pairing. Breeding pairs maintain a fairly strict spacing pattern during spring (egg-laying period), but tolerate the presence of lone males within their territory. About 20 % of the birds are unpaired in spring: these are erratic subadult males, widowed males or males which became single after a divorce. In early summer the proportion of solitary birds reaches a peak (53 %) because of clutch incubation. During this period broods appear, but also groups consisting of birds that lost their nests or of nonnesting birds.
Seasonal home range areas vary from 2 to 190 ha and home range lengths (determined by the longest movement covered during one season) vary between 0.3 and 25 km according to the individuals. Home range size varies from season to season. Home range area thus decreases between early spring and spring. Then it increases in the late summer period to diminish markedly in winter; home range length also diminishes between early spring and spring then increases again in sum-mer. These seasonal variations are apparently induced both by the breeding cycle and by the food needs in relation to changes in the weather.
Further to these general trends, there is a marked difference in home range size between individual birds. It seems that from April to August this variability is neither sex- nor age related, but merely linked to the partridge's " breeding-life history" (whether the bird is paired, even for a short time, or not; bird having experienced nesting success, or not). From September till March, the differences in spatial behaviour between individual birds are seemingly not directly linked to sex, but to ethological factors, and/or to ecological factors like snow depth and duration of snow cover. Thus, some birds leave their breeding site without the occurrence of any apparent change in weather and settle at several kilometres from there to overwinter for 5-6 months. In March they move back to their former breeding range (a migration-like behaviour). Other birds leave their breeding sites only after heavy snow fall to reach areas that will rapidly be snow-free : some birds will stay there until March, but others move back to their breeding sites as soon as the snow has melted. Others still are wintering close to their breeding site.
Breeding birds use annual home ranges covering on average an area of 221 ha and measuring 6.7 km in length. Home range annual areas of individual birds vary little (from 194 to 338 ha). In contrast, there is a 1- to 12-fold difference in home range lengths according to the individual. Because of the long distances moved by the birds, all favour-able habitats situated within a radius of at least 6-7 km from the breeding area should be managed, if the goal is to maintain a nucleus of breeders.
Status, trends and limiting factors of rock partridge (Alectoris graeca) populations: a literature survey. Gibier Faune Sauvage - Game and Wildlife, 1994, Vol. 11 (Hors série Tome 1) : 267-307.
In this work we present a synthesis of knowledge of the territorial and hunting status of rock partridge (Alectoris graeca), its population trends, ecological requirements, and the limiting factors responsible for the decline of populations in France and Italy. The rock partridge is a true European species which inhabits the Alpine and Apennine mountain ranges and Sicily, as well as the Balkan peninsula.
It is present in France, Italy, Switzerland, Germany, Austria, former Yugoslavia, Albania, Greece and Bulgaria.
In France, the species only inhabits the Alps. Over the last 25 years (1964-
1989), its distribution range has remained stable in the inner mountain massifs between Savoy and the Maritime Alps, but regressed markedly on the northern, northwestern and western boundaries of the French Alps. Since the end of the eighties, however, the species seems to have recolonized certain massifs in the Northern Alps where ten years earlier it was thought to be on the verge of extinction. Mean spring densities recorded in 13 representative sample areas are between 1.2 and 3.8 males per 100 ha. The eleven populations that were monitored for more than six years have remained stable. Rock partridge population abundance in France is about 2,000-3,000 pairs.
In Italy, the rock partridge occupies the Alpine mountain chain, the central and southern parts of the Apennines and Sicily. It disappeared from the Ligurian-Piedmont Apennines, the Pavia Apennines, the Tuscan-Emilian Apennines and the Apuanian Alps as early as at the end of the nineteenth century or the beginning of the twentieth century. More recently, (between 1960 and 1980) it disappeared from the Lombardian pre-alps and the Carso region (province of Trieste). Its distribution range also regressed markedly in Sicily. Rock partridge numbers also seem to have dropped in the Italian Alps as well as in the Apennines and Sicily. Population size in Italy is an estimated 13,000-20,000 pairs. Italy is therefore the country which is harbouring the greatest number of breeding rock partridges in the world.
Rock partridge can be shot in autumn in all countries it occupies, except in Austria and Switzerland, where the species is protected. There are shooting plans in two French departements. In certain regions of the Italian Alps shooting plans are envisaged. The annual shooting bag in France amounts to some 600 to 1,000 birds.
Rock partridge like open and hilly habitats, situated between 700 and 3.000 m in the Alps, between 400 and 2.500 m in the Apennines and between 40-50 m and 2,500 m in Sicily. Since the 1950's- 1960's, there has been a drop in mountain population numbers. The main cause for this is probably the abandonment of farming activities accompanied, especially at low and mean altitudes, by closure of the open habitats due to a spontaneous reforestation of the south-facing slopes that are left fallow. These changes in mountain range utilization have resulted in a deterioration and even loss of habitat for wintering and breeding rock partridges. There are other negative factors that should be taken into account: building of skiing facilities on mountain crests where the birds winter quarters are situated, a succession of winters with heavy snow, the presence of huge domestic herds in the mountain pastures during the nesting period, overshooting, the introduction of hand-reared partridge of the genus Alectoris (A. rufa, A. chukar) or intoxication by chemical herbicides (in Sicily).
The chapter presents the status of the Rock Partridge in France (geographical distribution, abundance, habitat), the factors responsible for the decline of populations, monitoring methods, and hunting management practices
Game and Wildlife Science, vol. 17(2), June 2000, p. 63-79
Rock partridge Alectoris graeca saxatilis populations surveyed in the southern French Alps declined rapidly from 1994, reaching very low levels in 1997 and 1998. This decline could be due to the impact of several climatic events which occurred from 1994 through 1996. To evaluate the likelihood of this hypothesis, we examined two types of model population variations incorporating demographic parameters determined in a population of rock partridge surveyed since 1982 in the French department Alpes-Maritimes.
Population estimates of birds have many applications in conservation and ecological research, as well as being of significant public interest. This is the fourth report by the Avian Population Estimates Panel, following those in 1997, 2006 and
2013, presenting population estimates of birds in Great Britain and the United Kingdom. Overall, there are thought to be about 84 million breeding pairs of birds in the UK, similar to the total in APEP 3. The Wren Troglodytes troglodytes continues to be
the most common species, with a current estimate of 11 million pairs, which has increased since APEP 3. There are more than one million pairs of 20 species (23 in APEP 3) and these 20 species contribute 77% of the total (58% of the total is accounted for by the ten commonest species alone). Population estimates originate from a wide variety of sources, many involving extrapolation of previous estimates by recognised trend measures. Despite the often exceptionally detailed information available on bird numbers, there remain many gaps in our knowledge. Recommendations are made to improve our understanding of bird numbers nationally.
Flocking is a compromise between costs and benefits, and we argue that the degree of benefit depends on individual position within the flock. By continuous observations from a tower, complete film records of all feeding visits by brent geese Branta bernicla bernicla to selected plots during the spring staging season were obtained. Analysis of these films coupled with before-and-after stereo photos of the vegetation confirmed that the vegetation was rapidly depleted, resulting in less than 10 individuals using patches of 800 cm 2 covered by the initially preferred food plant Plantago maritima. The lower level of acceptance appeared related to the intake rate of the alternative food species Puccinellia maritima. The first birds that visited the plots had a higher intake rate and tended to make a different selection from the plants on offer compared with birds at the rear end of the flock. The diet composition appeared a good predictor of the birds' foraging success. The large asymmetries in resource allocation became evident from the use of Plantago; only 12% of the individuals took 50% of the total crop. The film analyses suggested that successful Plantago feeders, which spent long times in rich patches, lost their front position in the flock. To catch-up with the front birds they walked fast while temporarily feeding on Puccinellia. The herbivores studied faced similar problems as many predators do, i.e. their food was distributed in a patchy way and stocks were rapidly depleted. Optimal foraging theory developed for predators is therefore an appropriate tool to understand foraging decisions in herbivores.
Heterospecific grouping is often associated with reduced predation. One example of this phenomenon is birds breeding in association with more aggressive species. Here we report a study of the association between breeding ducks and small colonial gulls during the nesting and brood-rearing periods in boreal wetlands in Finland. Dabbling duck nests were rarely found within gull colonies, while Tufted Duck (Aythya fuligula) and Pochard (Aythya ferina) nests were exclusively found within gull colonies.During the brood stage, the broods of most duck species were found more often than expected within the colony areas of small gulls, such as the Black-headed Gull (Chroicocephalus ridibundus) and Little Gull (Hydrocoleus minutus). Dabbling duck broods in particular were associated with gulls. In diving ducks, Tufted Duck broods preferred gull defence areas, whereas Common Goldeneye (Bucephala clangula) broods did not. We suggest that colonies of small gulls may be much more important for ducks than previously thought. In recent years, Black-headed Gull populations have decreased in Finland, and the populations of Tufted Duck and Pochard have concurrently decreased.We recommend that the nesting site requirements of small colonial gulls should be taken into account in wetland restoration and when building new wetlands.
Common Eiders Somateria mollissima in Shetland are believed to be essentially resident within the archipelago, and may be closer to S. m. faeroensis than to S. m. mollissima, the subspecies found in mainland Scotland. Surveys during the late summer moulting period indicated the population in Shetland declined from an estimated 15,500 birds in 1977 (subsequently revised to 17,000) to c. 6,000 by 1997. Further surveys in August 2009 and August 2012 located 5,782 and 4,627 birds, respectively. The 2009 count suggested little change in numbers since the late 1990s, whilst the 20% difference between 2009 and 2012 is believed to represent a genuine decrease rather than any artefact of survey coverage or accuracy. The distribution of moulting Eiders changed fundamentally during the 2000s, from traditional sites on the exposed, outer coastline to the vicinity of shellfish and finfish aquaculture sites on the sheltered, inner coastline; by 2009-12 approximately two-thirds of the moulting population was associating with aquaculture sites. The reason for the recent decrease in the population is unknown, but possible contributory factors discussed include mortality from oil pollution, deterrence measures taken at aquaculture sites, and predation by marine mammals, especially by Killer Whales Orcinus orca.