Piersma, Theunis

Wiersma, Popko

English

This paper explores whether the visual scoring of abdominal profiles can be used to evaluate variation in energy stores of shorebirds. Carcass analyses showed that the mass of fat in the abdominal cavity is well correlated with total fat mass and body mass. In May 1990, abdominal profiles were scored of Red Knots (Calidris canutus, subspecies canutus) on their last spring staging area in northern Germany before the 4000-5000-km long flight to the Siberian-arctic breeding grounds. Scores made in the field varied between 1 (concave shape of abdomen) to 5 (bulging). Average abdominal profile scores increased significantly over time in May 1990, paralleled by an increase in body mass, as based on catches of Red Knots in earlier years. At the end of May the average abdominal profile decreased, presumably due to the departure of adult Red Knots, leaving lean, perhaps mainly immature, birds behind. The scale of abdominal profile scores is probably too coarse to estimate fat content of individual waders. On a cohort level, however, the measure has much potential for comparisons of (re-)fuelling rates between different groups, feeding areas and years without the need to obtain large samples of captured birds.</p

ARTS repository - University of Groningen

Scoring abdominal profiles to characterize migratory cohorts of shorebirds:An example with Red Knots

https://pure.rug.nl/ws/files/3264464/1995JFieldOrnitholWiersma.pdf

Scoring abdominal profiles to characterize migratory cohorts of shorebirds:An example with Red Knots

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ARTS repository - University of Groningen