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In the summer of 2002 a combined Dutch-Russian expedition took place to the Willem Barentz field station at Medusa Bay near Dikson in north-western Taimyr, Russia. The expedition was organised by Alterra and the Agricultural Department of the Dutch Embassy in Moscow. Research questions addressed by the Alterra team and basic results obtained during the 2002 season are presented in this report. More elaborate analyses and discussion of the data will be made elsewhere. Where useful, results are compared with data collected in 2000 and 2001. Subjects of study generally concerned breeding biology of arctic breeding shorebirds, especially with respect to timing of breeding.

This report describes the Wader Energy Balance and Tidal Cycle Simulator WEBTICS. The model simulates food uptake of Oystercatchers (Haematopus ostralegus) and a distribution of the birds over exposed parts of tidal areas. The mudflats are described on input as a number of spots which have a position, height and surface area. Spots may contain prey items characterized by type, weight and density. The program simulates tidal cycles and calculates the fraction of time the average and ideal bird has to spend feeding in order to meet its energy requirements. These foraging intensities are combined into a stress index for the winter. Besides historical data on weather, prey distribution, tides and fishing, there are bird and prey parameters on foraging, prey growth and energy conversion. Model output files can be processed in a spreadsheet. Also bitmapped images and movies are produced.

Dit rapport bevat een analyse van de voedselsituatie van scholeksters gedurende de negentiger jarenin de Waddenzee. Het aantal overwinterende scholeksters is afgenomen van 266 000 in de jaren tachtig tot 170 000 aan het eind van de jaren negentig. De oorzaak is een tekort aan voedsel dat in de eerste plaats is veroorzaakt door het ontbreken van mosselbanken die rond 1990 zijn verdwenen ten gevolge van strenge winters, bevissing en stormen. De tweede oorzaak is de kokkelvisserij die de draagkracht van het Waddengebied voor scholeksters met ongeveer 12% heeft verminderd. De hoeveelheid voedsel die nodig is voor een stabiel aantal scholeksters bedraagt naar schatting 200 kg kokkelvlees per scholekster of 1 ha stabiele mosselbank voor iedere 35 scholeksters. Aan het eind van de negentiger jaren was die hoeveelheid kokkelvlees aanwezig en is het aantal scholeksters ook weer licht gestegen.

In dit rapport worden de meest recente gegevens over het voorkomen van trekkende watervogelsoorten in de polder de Zeevang en omgeving (Noord-Holland) samengevat. Op grond van de drempeloverschrijdende aantallen overwinterende smienten (Anas penelope)wordt geadviseerd de Zeevang aan te wijzen als speciale beschermingszone onder de EG-Vogelrichtlijn.

Missile tests in the Meldorfer Bucht have been under debate for many years, especially since the test area has become part of the National Park Schleswig Holsteinisches Wattenmeer. Alterra Texel, as an independent institute involved in biological research in the Wadden Sea for many years, has been asked to quantify the effects of these tests by means of a brief field study. The results presented in this report are based on observations during a single observation day. Our results are combined with theoretical predictions and data from earlier studies. It appears that the use of helicopters for making clear range flights and for collecting the remains of the missile from the mudflats have the highest impact, especially because of disturbance of birds. Some thousands of waders and other waterbirds are disturbed briefly. The impact of these disturbances, expressed as extra energy expenditure for birds, can be classified as small. The number of macrobenthic animals (like worms and shellfish) killed by the missile landing on the tidal flats can be classified as very small. Although our study has been short and relatively superficial we believe that the results can be considered as a valid expert opinion on the most relevant implications of the impact of weapon technology trials in this area.

In the Summer of 2001 a combined Dutch-Russian expedition took place to the Willem Barentz field station at Medusa Bay near Dikson in north-western Taimyr. The expedition was organized by Alterra, the Working Group for International Waterbird and Wetland Research (WIWO) and the Agricultural Department of the Dutch Embassy in Moscow. The results obtained by the Alterra team are presented in this report. Subjects of study generally concerned breeding biology of arctic breeding shorebirds, especially aspects related to timing of breeding and adult body condition. This report's purpose is not to discuss the findings thoroughly but merely to summarize the research questions addressed and present all basic information collected during the 2001 season. Topics included are spring arrival and autumn departure of waders from the tundra, breeding phenology, nest success, biometrics of adult waders, chick growth rate, return rates of adult shorebirds, and seasonal and weather-related variation in arthropod availability. Where useful, results are compared with data collected in a previous expedition in 2000. More elaborate analyses and discussion of the data will be made elsewhere.

In het verleden zijn door het RIKZ in het Zeehavenkanaal te Delfzijl hoge hexachloorbenzeengehalten gemeten. Na sanering voldeed de onderwaterbodem voor hexachloorbenzeen echter nog steeds niet aan de normen voor het baggerbeheer. In eieren van scholeksters die foerageren in het met hexachloorbenzeen verontreinigde gebied, zijn ook verhoogde concentraties gemeten. De vraag is of deze verhoogde concentraties hexachloorbenzeen en eventuele andere verontreinigingen nadelige effecten hebben op de scholeksters. Uit het onderzoek waarvan de resultaten in dit rapport beschreven staan, blijkt dat de in de eieren aanwezige stoffen in staat zijn om effecten bij vogels te veroorzaken.