Tag: all of Calidris

Modelling phenotypic flexibility: an optimality analysis of gizzard size in Red Knots Calidris canutus

Red Knot (Calidris canutus) Science Article 13 abstract Reversible phenotypic changes, such as those observed in nutritional organs of long-distance migrants, increasingly receive the attention of ornithologists. In this paper we review the cost-benefit studies that have been performed on the flexible gizzard of Red Knots Calidris canutus. By varying the hardness of the diet […]

Digestive bottleneck affects foraging decisions in red knots Calidris canutus. I. Prey choice

Red Knot (Calidris canutus) Science Article 14 abstract Rate-maximizing foragers that only divide their time between searching and handling prey should, according to the classical contingency model (CM), only select those prey whose energy content per unit handling time (i.e. profitability) exceeds or equals long-term average energy intake rate. However, if digestively constrained foragers were […]

Southward migration and fuel deposition of Red Knots Calidris canutus.

Red Knot (Calidris canutus) Science Article 10 abstract We compared the differences between spring and autumn in migration speed, fuelling rates and fuel loads of migrating Red Knots Calidris canutus. As a basis we used ringing data from Ottenby Bird Observatory, southeastern Sweden, collected 1948-2003, with morphometrical data from 1990-2003. Numbers ringed varied between 0 […]

Body transformations, condition, and survival in Red Knots Calidris canutus travelling to breed at Alert, Ellesmere Island, Canada.

Red Knot (Calidris canutus) Science Article 11 abstract This paper reviews the nutrient storage dynamics and body changes of Red Knots Calidris canutus islandica during migration through their final spring stopover area in Iceland and after arrival on the breeding grounds in the northeastern Canadian High Arctic at Alert. In Iceland, Knots not only accumulate […]

Two estimates of the metabolic costs of antibody production in migratoryshorebirds: low costs, internal reallocation, or both?

Red Knot (Calidris canutus) Science Article 5 abstract We measured the costs of mounting a humoral immune response using two novel antigens (tetanus and diphtheria) in two shorebird species (Scolopacid ): Red Knot (Calidris canutus, measured in autumn) and Ruff (Philomachus pugnax, measured in spring). Metabolic rate was measured during the preinjection phase, at the […]

Fuel use and metabolic response to endurance exercise: a wind tunnel study of a long-distance migrant shorebird

Red Knot (Calidris canutus) Science Article 2 abstract This study examines fuel use and metabolism in a group of long-distance migrating birds, red knots Calidris canutus (Scolopacid ), flying under controlled conditions in a wind tunnel for up to 10 h. Data are compared with values for resting birds fasting for the same time. Plasma […]

Changing balance between survival and recruitment explains population trends in Red Knots Calidris canutus islandica wintering in Britain, 1969-1995

Red Knot (Calidris canutus) Science Article 9 abstract The demography of Red Knots Calidris canutus islandica wintering in Britain from 1969 to 1995 was examined using published data on winter numbers, unpublished ringing data, and information on the percentages first year birds in late autumn and winter (defined here as ‘recruitment’). The maximum time between […]

Arrival and weight gain of Red Knot Calidris canutus, Ruddy Turnstone Arenaria interpresand Sanderling Calidris alba staging in Delaware Bay in spring

Red Knot (Calidris canutus) Science Article 16 abstract Delaware Bay is an important spring staging area for shorebirds migrating north along the easternAmerican coast, with birds relying heavily on Horseshoe Crab Limulus polyphemus eggs duringtheir stay. While many species use the Bay, three species are of particular interest: Red KnotCalidris canutus, Ruddy Turnstone Arenaria interpres […]

Reconstructing palaeoflyways of the late Pleistocene and early Holocene Red Knot Calidris canutus.

Red Knot (Calidris canutus) Science Article 12 abstract Bird migration systems must have changed dramatically during the glacial-interglacial cycles of the Pleistocene and as novel habitats became available since the last glacial maximum. This study combines molecular dating of population divergence times with a review of polar-centred palaeovegetation and intertidal habitats world-wide to present a […]

Distribution, migrations and biometrics of Knots Calidris canutus canutus on Taimyr, Siberia

Red Knot (Calidris canutus) Science Article 7 abstract Studies carried out in northern Taimyr in 1982-84 and 1990-92 were combined with data from other sources to describe the breeding distribution and densities and the migration of Knots at Taimyr Peninsula, north-central Siberia. Morphometrics, recent ring recoveries, dates and directions of migration all support the idea […]