Changes in abundance of water birds species in southern Bohemia (Czech Republic) in the last 10 years

In 1981–1992, the breeding fauna of 153 fishponds was studies in three fishpond regions in south Bohemia (Czechoslovakia). On each pond, all water and wetland birds were censused by the Two-check method, which consists of adult birds counts during each breeding season (the first in the second part of May, and the second in the second part of June). We assessed the numbers of all species living in water and wetland habitats in the breeding season.The decline in abundances (expressed as number of individuals) of ducks (Anatinae), grebes (Podicipediformes), Coot (Fulica atra), Moorhen (Galinulla chloropus), Black-headed Gull (Larus ridibundus) were the most marked changes recorded. Marked increase in abundances was found in Cormorant (Phalacrocorax carbo) and Mute Swan (Cygnus olor) during the whole decade, whereas in Graylag Goose (Anser anser) the increase was restricted to the first half of the period under study. Numbers of charadriform and passeriform birds fluctuated in the dependence of water level variation.     

High altitude tissue adaptation in Andean coots: capillarity,fibre area,fibre type and enzymatic activities of skeletal muscle

Capillarity, fibre types, fibre area and enzyme activities of different skeletal muscles (pectoralis, extensor digitorum longus), tibialis anterior, plantaris and the myocardium were compared in Andean coot (Fulica americana peruviana) native to high altitude (Junín, Perú, 4200 m) and the same species nesting at sea level. Numbers of capillaries per square millimeter were higher in all high-altitude muscles when compared with sea-level muscles (P<0.0001). Moreover, values for capillaries per fibre and capillaries in contact with each fibre were higher in digitorum and tibialis high-altitude muscles. Muscle fibres were classified as Type I, Type IIA or Type IIB on the basis of their myofibrillar ATPase pH lability. Pectoralis muscle of high-altitude and sea-level coots presented only fibres of Type IIA. In contrast, all the leg muscles studied showed a mosaic pattern of the three fibre types. Fibre areas were determined using a Leitz Texture Analysis System. Significant differences in fibre area were observed (P<0.01) between high-altitude and sea-level muscles. Mean muscle fibre diameters were also lower in the high-altitude group than in the sea-level group. The enzyme activities studied were hexokinase, lactate dehydrogenase, citrate synthase and 3-hydroxyacyl-CoA-dehydrogenase. The oxidative capacity, as reflected by citrate synthetase and hydroxyacyl-CoA-dehydrogenase activities, was greater for myocardial and pectoralis than for leg muscles. However, analysis of maximal enzyme activities showed that there were no significant differences between the glycolytic and oxidative enzyme activities of high-altitude and sea-level coots. These results suggest that in Andean coots genetically adapted to high altitude, changes in muscle capillarity and fibre size, in addition to high haemoglobin O₂ affinity and low haemoglobin concentration, are sufficient to allow adequate energy production without increases in enzymatic activities.Abbreviations BSA bovine serum albumin - C:F ratio Capillaries per fibre - CAF Capillaries in contact with each fibre - CD capillary density (mm^-2) - CS citrate synthetase - EDL muscularis digitorum longus - fra fraction reduction area - HA high altitude - HAD hydroxyacyl-CoA-dehydrogenase - HK hexokinase - LDH lactate dehydrogenase - P ₅₀ PO₂ at which hemoglobin is half saturated with O₂ - P _aO₂ arterial partial pressure of oxygen - PAS periodic acid-schiff - PEC muscularis pectoralis - PLA muscularis planaris - P _tO₂ mean tissue oxygen pressure - P _vO₂ mixed venous partial pressure of oxygen - SD standard deviation - SL sea level - TA muscularis tibialis anterior - TAS texture analysis system     

Combining archive territory mapping data and aerial photography to investigate bird–habitat relationships: a case study from the Lincolnshire coast

Capsule Habitat associations of breeding birds in a complex coastal environment are clear, interpretable and mostly consistent between years.

Aims To match archive territory mapping data with historical aerial photographs and develop data handling and analytical techniques for the study of bird–habitat relationships.

Methods Bird registrations were digitized from archive British Trust for Ornithology Common Birds Census maps and habitat characteristics from contemporaneous aerial photographs. The resulting maps were overlaid and ranks of habitat preference for 15 species calculated using compositional analysis. Similarity analysis identified species with consistent habitat profiles across years. Cluster analysis identified groups of species with similar patterns of habitat use.

Results A total of 5400 registrations of 15 species in 14 habitats were analysed. Of these, 13 species showed stable patterns of habitat association across survey years. Clear differences and similarities in habitat preferences among the species were identified. The results may be used to inform conservation and management programmes in this and similar environments.

Conclusions Extensive archives of bird survey data can be used to study bird–habitat relationships and to measure the effects of natural and anthropogenic environmental change if contemporaneous aerial photographs can be sourced.     

Submersed macrophytes as a food source for wintering waterbirds at Lake Constance

We investigated the relationship between Charophytes and herbivorous waterbirds in the littoral zone of Lake Constance by quantifying their seasonal dynamics. The waterfowl extensively consumed Charophyte vegetation in shallower areas (<1 m water depth) at the beginning of the winter season, while deeper regions were only used in late winter. By the end of winter, the waterfowl had almost completely depleted the available Charophyte biomass down to a water depth of approximately 2 m (relative to average mean water level (AML)). Enclosure experiments revealed that senescence processes had a negligible influence on Charophytes biomass loss until early February. Coot, Red-crested Pochard and Pochard are the main avian Chara consumers in winter. Despite their great influence on biomass in winter, their influence on subsequent Charophyte regeneration is probably limited in Lake Constance, since Charophytes as typical pioneer species produce innumerable diaspores forming dense Charophyte meadows at a depth of between 1 and 4 m every year.     

Red-gartered Coot Fulica armillata feeding on the grapsid crab Cyrtograpsus angulatus: advantages and disadvantages of an unusual food resource

The behaviour of Red-gartered Coots feeding on an unusual food source was examined at Mar Chiquita Coastal Lagoon, Argentina. The grapsid crab Cyrtograpsus angulatus made up all observed prey items, and 61% were small. Both handling and foraging duration increased with the size of captured crabs, but foraging efficiency decreased. Crab availability affected both the dive duration of the Coots and their foraging decisions with regard to prey-size selection. Two species of gull were observed kleptoparasitizing Coots, especially when the Coot was handling medium or large crabs. Feeding by Coots on Cyrtograpsus angulatus has not been previously documented and may be a feeding innovation. Our estimations suggest that Coots were foraging optimally, since smaller crabs were more energetically profitable.     

Polymorphic microsatellites identified by cross-species amplifications in the European Coot Fulica atra

We tested the cross-amplification of 26 microsatellites developed for passerines and an additional three developed for Gallinula species in eight European Coots from two populations. Sixteen microsatellite markers successfully amplified, of which nine were polymorphic with 2–6 alleles (mean 3.7 alleles) and an expected heterozygosity (H _e) ranging from 0.375 to 0.805 (mean H _e = 0.589). On average, we found 2.22 alleles/locus and a mean H _e of 0.440 in one nest, and 2.56 alleles/locus and a mean H _e of 0.494 in the other one. These nine polymorphic markers could be of potential use in studies of genetic variability, population structure and reproductive strategy of European Coots.     

骨顶鸡的种内巢寄生现象及其抵御机制初探

在2008～ 2009年2个繁殖季节对黑龙江省安邦河湿地自然保护区和大庆龙凤湿地自然保护区的骨顶鸡( Fulica atra)种群进行了调查.结果发现,骨顶鸡具有很高比例的种内巢寄生现象,平均巢寄生比例达38.55％;且发现骨顶鸡具有类似于同属的美洲骨顶鸡(F.americana)的拒卵方式,主要包括埋卵、逐出和啄破....     

Paternity-parasitism trade-offs: a model and test of host-parasite cooperation in an avian conspecific brood parasite

Efforts to evaluate the evolutionary and ecological dynamics of conspecific brood parasitism in birds and other animals have focused on the fitness costs of parasitism to hosts and fitness benefits to parasites. However, it has been speculated recently that, in species with biparental care, host males might cooperate with parasitic females by allowing access to the host nest in exchange for copulations. We develop a cost-benefit model to explore the conditions under which such host-parasite cooperation might occur. When the brood parasite does not have a nest of her own, the only benefit to the host male is siring some of the parasitic eggs (quasi-parasitism). Cooperation with the parasite is favored when the ratio of host male paternity of his own eggs relative to his paternity of parasitic eggs exceeds the cost of parasitism. When the brood parasite has a nest of her own, a host male can gain additional, potentially more important benefits by siring the high-value, low-cost eggs laid by the parasite in her own nest. Under these conditions, host males should be even more likely to accept parasitic eggs in return for copulations with the parasitic female. We tested these predictions for American coots (Fulica americana), a species with a high frequency of conspecific brood parasitism. Multilocus DNA profiling indicated that host males did not sire any of the parasitic eggs laid in host nests, nor did they sire eggs laid by the parasite in her own nest. We used field estimates of the model parameters from a four-year study of coots to predict the minimum levels of paternity required for the costs of parasitism to be offset by the benefits of mating with brood parasites. Observed levels of paternity were significantly lower than those predicted under a variety of assumptions, and we reject the hypothesis that host males cooperated with parasitic females. Our model clarifies the specific costs and benefits that influence host-parasite cooperation and, more generally, yields precise predictions about expected levels of host male paternity. These predictions will enable a more rigorous assessment of field studies designed to test adaptive hypotheses of host-parasite cooperation.     

Distribution shifts in wintering Golden Plover Pluvialis apricaria and Lapwing Vanellus vanellus in Britain

Capsule The winter distribution of Golden Plover and Lapwing has shifted east since the mid-1980s, perhaps in response to climate change.

Aims To combine analyses of winter trends on wetlands and flocks on farmland to assess the current status of Golden Plover and Lapwing in one of their main wintering regions.

Methods Winter trends were derived from monthly counts on estuaries and wetlands for the period 1974–2002 (the Wetland Bird Survey). Winter distribution on farmland was assessed using casual records of large flocks and surveys of a stratified random sample of 1-km squares (the Winter Farmland Bird Survey).

Results Regional trends showed a pronounced increase in numbers of both species since 1974 on the east coast, with a smaller increase on the south coast. Numbers in the west and north tended to decline. Flocks on farmland were concentrated in eastern Britain unlike the situation in the 1980s.

Conclusions The winter distribution of Golden Plover and Lapwing has shifted to the east, resulting in large numbers on the east coast and in the arable east of Britain. The implications of this shift, especially in relation to known habitat associations, are discussed.