Richard Hearn

Differential migration of the sexes cannot be explained by the body size hypothesis in Teal

The “body size hypothesis” predicts that if individuals of a population migrate different distances from the breeding to the wintering grounds, the distance should be related to the differential ability to cope with adverse conditions, with larger individuals wintering further north. Data collected over a 40-year period in Essex, UK and the Camargue, southern France, revealed that the average body mass of Teal ringed in Essex during these years was actually not greater than that of Teal ringed in the Camargue. A higher proportion of males were included in the UK ringing catch than in the French catch, but we found no support for the body size hypothesis to explain such differential migration of the sexes.

Changes in ring recovery rates over the last 50 years: shall we continue to ring ducks?

Although knowledge of ring recovery rate is of crucial importance to establish demographic parameters, such as survival probability, this information is generally unknown for the dabbling ducks. The almost single existing value from the North American Mallard (Anas platyrhynchos) is thus generally applied to other species or geographic areas, even though this assumption may be strongly misleading. In the study reported here, we have relied on a proxy for actual ring recovery rate, namely, the proportion of rings fitted each year that were eventually reported, to test for differences between duck species (Mallard and Teal Anas crecca) and between countries [England (UK) and France] for Teal. Potential trends over time (1952–2005) were also assessed. Ring recovery rate was found to have sharply decreased and at a similar rate over time in both species in France, and in both countries for Teal (e.g. from 22.7% in 1952 to 7.2% in 1992 for the British Teal). Teal rings were, however, reported more frequently than Mallard ones, and Teal rings were more frequently reported in the UK than in France. In recent years, a phone number for reporting the information has been included on the bird mark, with the immediate result of a doubling in the recovery rate in France. Adaptations to current ringing procedures that would improve ring reporting would appear to be necessary in the future if researchers are to keep ringing as a valuable source of information for bird demography studies.

Comparing the migration of Eurasian Teal Anas crecca from two main wintering areas of Western Europe: A long‐term study from Essex, England, and the Camargue, France

MATTHIEU GUILLEMAIN1*, RICHARD HEARN2, ROY KING2, MICHEL GAUTHIER-CLERC3, GERALDINE SIMON3 and ALAIN CAIZERGUES4 1Office National de la Chasse et de la Faune Sauvage, CNERA Avifaune Migratrice, La Tour du Valat, Le Sambuc, 13200 Arles, France 2Wildfowl & Wetlands Trust, Slimbridge, Gloucester GL2 7BT, UK 3Centre de Recherche de la Tour du Valat, Le Sambuc, 13200 Arles, France 4Office National de la Chasse et de la Faune Sauvage, CNERA Avifaune Migratrice, 39 Bd. Albert Einstein, CS42355, 44323 Nantes,Cedex 3, France

Breeding performance and timing of breeding of inland and coastal breeding Cormorants Phalacrocorax carbo in England and Wales

Capsule Breeding performance was higher at inland colonies than on the coast due to higher nestling survival during late development. Aims To compare breeding performance of inland and coastal breeding Cormorants in England and Wales and to provide breeding performance data for Cormorants for future demographic studies. Methods Breeding performance and timing of breeding was monitored at six inland and four coastal colonies during 1997 and 1998. We compare clutch and brood size and egg and nestling survival. Results Breeding performance was higher at inland colonies because of higher nestling survival during the later stages of nestling development, from 15–56 days. Conclusions Greater and earlier food availability at inland colonies, resulting in earlier and more protracted breeding is the most probable explanation for differences in breeding performance. A more protracted breeding season would reduce competition for food and enhance breeding performance, which may be especially apparent during late chick development when energy demands are greatest.

Within-winter movements and site fidelity of Icelandic Greylag Geese Anser anser

Capsule Levels of mobility and turnover changed at different stages of the non-breeding season. Aims To describe the pattern of within-winter movements of Icelandic Greylag Geese in northern Britain and to assess the rate of turnover at different stages of the non-breeding season. Methods Sightings of marked individuals were used to describe movements throughout the wintering range, while more detailed local studies were used to assess rates of turnover. Results Greylag Geese were most mobile and turnover greatest during the early winter period (October–December). Birds were least mobile and turnover lowest during the midwinter period. In spring (March–April) rates of turnover slightly increased as did movement between areas. Despite this it seemed that most birds probably made a direct flight to Iceland from their final wintering area without staging in north Scotland. Conclusions Greylag Geese were highly mobile, particularly on arrival from their Icelandic breeding grounds. They were less mobile in midwinter and spring. There was little evidence of a northerly return movement within Britain in spring. Most departed to Iceland directly from their final wintering locations. Evidence of an expansion in the known range is also presented.

Time series analysis reveals synchrony and asynchrony between conflict management effort and increasing large grazing bird populations in northern Europe

Abstract The management of conflicts between wildlife conservation and agricultural practices often involves the implementation of strategies aimed at reducing the cost of wildlife impacts on crops. Vital to the success of these strategies is the perception that changes in management efforts are synchronized relative to changes in impact levels, yet this expectation is never evaluated. We assess the level of synchrony between time series of population counts and management effort in the context of conflicts between agriculture and five populations of large grazing birds in northern Europe. We reveal inconsistent patterns of synchrony and asynchrony between changes in population counts and impact management effort relating to population harvesting, monetary payments, or scaring practices. This variation is likely due to differing management aims, the existence of lags between management decisions and population monitoring, and the inconsistent use of predictive models across case studies. Overall, our findings highlight the need for more adaptive and timely responses of management to changes in target species numbers so as not to unexpectedly increase social conflicts and jeopardize the status of wildlife populations.

Ready for climate change? Geographic trends in the protection status of critical sites for Western Palearctic ducks

The geographic range of many migratory bird populations is shifting in response to climate change. Protected areas play a major role in the conservation of many such species, yet these reserves are static so a geographic mismatch between the habitat needs of the birds and the network of protected areas may gradually appear. Ducks in the Western Palearctic are most likely to shift their distribution northwards and eastwards in response to climate change, so we evaluated whether the mean protection level of the most critical sites for ducks shows any latitudinal or longitudinal trend. From the description of site protection level in the Critical Site Network database (little/none to full protection) a site protection score was computed, ranging from 0 (little/none) to 3 (full protection). More northern sites had greater mean protection scores. Conversely, a negative longitudinal gradient was identified, with much poorer protection of critical duck sites in Eastern Europe, the Middle East and Central Asia. This is where duck populations are currently the largest, and among the areas where duck populations are expected to increase in the future following climate change, although currently a relatively high proportion also show decreasing population trends. The site protection score was also greatest, on average, in member states of the European Union rather than in other European countries, suggesting EU directives have been successful at improving the level of protection of the most important wetlands for ducks. Although ducks could benefit from further conservation of the sites they use anywhere within their geographic range, and there is room for improvement of protection score in all areas, this study suggests that future site protection efforts should be internationally coordinated, and first targeted at sites east of the Mediterranean shore.