First geolocator tracks of Swedisch red-necked phalaropes reveal the Scandinavia - Arabian Sea connection
Bemmelen, R.S.A. van; Hungar, J. ; Tulp, I.Y.M. ; Klaassen, R.H.G. - \ 2016
Journal of Avian Biology 47 (2016)3. - ISSN 0908-8857 - p. 295 - 303.
We studied migration and wintering patterns of a wader with a pelagic lifestyle during the non-breeding period, the rednecked phalarope Phalaropus lobatus . Using light-level geolocation, we obtained three full annual tracks and one autumn migration track of male red-necked phalaropes caught during breeding in Scandinavia. Th ese tracks confi rmed expectations that individuals from the Scandinavian population winter in the Arabian Sea. Migration was accomplished in two to four migration leaps, staging for a few days in the Gulf of Finland (autumn) or the southern Baltic Sea (spring) and for up to a month in or near the Black and Caspian Sea (autumn and spring). In addition, travel speeds suggested that only the fl ights between the Baltic and Black/Caspian Sea are non-stop, and thus the birds seem to make additional short stops during the other flights. Stopover time in the Black/Caspian Sea is only 8 – 10 d in spring but up to 36 d in autumn, which is longer than expected if only used for pre-migratory fattening to cover the ca 2000 km to the Gulf of Oman. After entering the Arabian Sea via the Gulf of Oman, birds dispersed over the entire presumed winter range. Winter movements appear to correspond to the spatio-temporal patterns in primary production linked to seasonally changing monsoon winds. Th ese are not only the first tracks of Scandinavian red-necked phalaropes, but also the fi rst seabird tracks in the Arabian Sea, one of the most productive and dynamic marine areas on the planet.
Analyse effectiviteit van het akkervogelbeheer in Provincie Groningen : Evaluatierapport
Wiersma, P. ; Ottens, H.J. ; Kuiper, M.W. ; Schlaich, A.E. ; Klaassen, R.H.G. ; Vlaanderen, O. ; Postma, M. ; Koks, B.J. - \ 2014
Scheemda : Stichting Werkgroep Grauwe Kiekendief (2 ) - 222
bouwland - akkerranden - agrarisch natuurbeheer - vogels - fauna - monitoring - groningen - arable land - field margins - agri-environment schemes - birds - fauna - monitoring - groningen
De Werkgroep Grauwe Kiekendief en zijn oprichter Ben Koks zijn belangrijke pioniers geweest in het agrarische natuurbeheer. In de loop van de jaren hebben zij – in samenwerking met verschillende universiteiten – onafhankelijk, degelijk en vooral kritisch onderzoek geëntameerd, waarbij niet al van te voren vaststond dat genomen maatregelen wel zouden werken. Dit rapport vat veel van dit belangrijke werk samen
Body condition of shorebirds upon arrival at their Siberian breeding grounds
Tulp, I.Y.M. ; Schekkerman, H. ; Klaassen, R.H.G. ; Ens, B.J. ; Visser, G.H. - \ 2009
Polar Biology 32 (2009)3. - ISSN 0722-4060 - p. 481 - 491.
calidris-canutus-islandica - red knots - energy-expenditure - tundra arthropods - ellesmere-island - fat reserves - migration - stores - survival - waders
Abstract Arctic breeding shorebirds carry substantial body stores on their long-distance migrations from their non-breeding grounds. Upon arrival at the breeding area the remains of these stores can be used for egg formation, insurance against poor feeding conditions or rebuilding organs. We quantified body condition (body mass, total body water, lean body mass and fat mass estimated using the deuterium dilution method) in seven shorebird species caught upon arrival in the Siberian Arctic. Arrival condition was compared with incubation condition in a subset of species. After correction for structural size, body mass was significantly lower at arrival than during incubation in most of the species (but 3¿18% above lean mass). Fat index (fat mass/lean mass) varied between 5.1 and 13.2%. Fat stores were estimated to enable survival for 0.6 days for the smallest and 2.5 days for the largest species. We discuss possible functions of arrival stores: insurance, egg-formation or rebuilding organs.
Movement of foraging tundra swans explained by spatial pattern in cryptic food densities
Klaassen, R.H.G. ; Nolet, B.A. ; Bankert, D. - \ 2006
Ecology 87 (2006)9. - ISSN 0012-9658 - p. 2244 - 2254.
correlated random-walk - searching behavior - patchy environment - bayesian foragers - bewicks swans - energy gain - heterogeneity - field - information - depression
We tested whether Tundra Swans use information on the spatial distribution of cryptic food items (belowground Sago pondweed tubers) to shape their movement paths. In a continuous environment, swans create their own food patches by digging craters, which they exploit in several feeding bouts. Series of short (1 m). Tuber biomass densities showed a positive spatial auto-correlation at a short distance (25 g/m2) and to a more distant patch (at 7¿8 m) if the food density in the current patch had been low (3 m) from a low-density patch and a short distance (
The influence of social interactions on the foraging path of Bewick's Swans Cygnus columbianus bewickii
Klaassen, R.H.G. ; Nolet, B.A. ; Bankert, D. - \ 2006
Ardea 94 (2006)3. - ISSN 0373-2266 - p. 477 - 484.
tundra swans - behavior - information - habitat - efficiency - migration - depletion - foragers - patterns - tubers
The efficiency in which high-density food patches are found is determined by the way foragers move between patches. In this study we explore the effect of social interactions on the foraging path, in particular the distance moved between patches. We studied Bewick¿s Swans Cygnus columbianus bewickii that foraged on belowground tubers of Fennel Pondweed Potamogeton pectinatus. We accurately mapped the foraging path of individual swans and determined the distances between visited patches. 24% of inter-patch movements are associated with social interactions. When a swan retreats from a patch because it is chased away by another swan, it moves a significantly larger distance to a patch than if the movement is not associated with a social interaction. Such longer movements are thought to reduce the rate at which high-density patches are encountered, and thus the energy gain rate a swan can achieve. We observed a strong social hierarchy in which families are dominant over pairs and singletons, and pairs are dominant over singletons, which represents a producer¿scrounger model. Singletons were most frequently observed to retreat from patches and are consequently thought to achieve the lowest gain rates, and also as a result exhibit the slowest speed of movement between patches. However singletons might partly compensate for more frequent retreats from patches by moving larger distances to arrive at the front edge of a flock where they encounter unexploited resources.
Dekker, J.J.A. ; Roodbergen, M. ; Klaassen, R.H.G. - \ 2002
Zoogdier 13 (2002)2. - ISSN 0925-1006 - p. 23 - 25.
bunzings - mustela - verkeersongevallen - biologische technieken - postmortale onderzoeken - lichaamsvet - vet - lichaamssamenstelling - dieranatomie - lichaamsconditie - voortplanting - dierfysiologie - voortplantingsgedrag - voedselvoorkeuren - polecats - mustela - traffic accidents - biological techniques - postmortem examinations - body fat - fat - body composition - animal anatomy - body condition - reproduction - animal physiology - reproductive behaviour - food preferences
Om meer te weten te komen over de verborgen leefwijze van de bunzing worden dieren die slachtoffer werden van het verkeer door Alterra ontleed en o.a. onderzocht op vethoeveelheid (als indicatie van de conditie), voorplantingsstatus (aanwezigheid van sperma, als indicatie van het mogelijke aantal worpen per jaar) en maaginhoud (voedselkeuze)