Red Knot (Calidris canutus) Science Article 4 abstract Although the energy costs of foraging and food processing in vertebrates may be considerable, they have rarely been quantified separately. Here we present estimates for both cost factors based on a series of trials with a shorebird, the red knot Calidris canutus, fed natural and artificial prey […]
Category: Charadriiformes
Endogenous circannual rhythmicity in a non-passerine migrant, the Knot Calidris canutus.
Red Knot (Calidris canutus) Science Article 8 abstract We present experimental evidence for endogenous control of circannual rhythms in a long-distance migratory wader, the Knot Calidris canutus. Six individuals of the subspecies canutus were caught during northward migration whilst staging in France, and were held together under constant temperature and photoperiodic conditions (15 degree C, […]
Where waders may parallel penguins: Spontaneous increase in locomotor activity triggered by fat depletion in a voluntarily fasting Knot.
Red Knot (Calidris canutus) Science Article 6 abstract A Knot Calidris canutus, kept with four conspecifics on an enclosed artificial outdoor tidal flat in The Netherlands, refused to feed on the available bivalve prey for a period of 18 days and thereby decreased in mass from 209 g to 107 g, at which point the […]
Length of stopover, fuel storage and a sex-bias in the occurrence of two subspecies of Red Knots Calidris c. canutus an d C.c. islandica in the Dutch Wadden Sea during southward migration.
Red Knot (Calidris canutus) Science Article 1 abstract During southward migration the Wadden Sea is the meeting place of Red Knots Calidris canutus of two subspecies that breed in either western Siberia (C. c. canutus) or north Greenland and north-east Can ada (C. c . islandica), but the details of their co-occurrence have not been […]
IMPACTS OF INTRASPECIFIC KLEPTOPARASITISM ANDDIET SHIFTS ON RAZORBILL ALCA TORDA PRODUCTIVITYAT THE GANNET ISLANDS, LABRADOR
Razorbill (Alca torda) Science Article 10 abstract Intraspecific kleptoparasitism, the stealing of food from members of the same species, has received widespread but mostly superficial attention in the scientific literature. However, the effects of such behavior can be significant. Here we report on high rates of intraspecific kleptoparasitism in the Razorbill Alca torda at the […]
Effects of island isolation and feral mink removal on bird communities (Alca torda) on small islands in the Baltic Sea
Razorbill (Alca torda) Science Article 7 abstract 1.) Predation has been suggested as a major cause affecting survival, reproductive success and behaviour in vertebrate prey populations. The breeding season is a critical phase because the essential difference between selecting the proper nest site may be a question of breeding success and failure. 2.) Islands may […]
Sexual Size Dimorphism and Assortative Mating in Razorbills (Alca torda)
Razorbill (Alca torda) Science Article 1 abstract My primary aim here is to report the first large data set of live, known-sex Razorbills and to identify the degree of sexual size dimorphism in a number of body measurements. This Study is part of a wider project on mating behavior of Razorbills based on color-banded breeding […]
Wear and loss of rings used on Razorbills Alca torda
Razorbill (Alca torda) Science Article 3 abstract On Grasholmen in the central Baltic Sea, 3,583 Razorbill Alca torda chicks were ringed with triangular Incoloy rings, and about half the birds were subsequently resighted. The resightings were used to calculate rates of turned rings, and 119 retrieved rings were used to calculate rates of wear and […]
Survival and age at first breeding in the Razorbill (Alca torda)
Razorbill (Alca torda) Science Article 2 abstract Observations of banded birds on Skokholm were made during daily visits to the cliffs between mid-March and mid-August (1971-73), and the work was continued by the staff of the Bird Observatory in 1974. In one study colony, The Bluffs, visited daily throughout the season, the birds became tame, […]
Sex differences in razorbill Alca torda parent-offspring vocal recognition
Razorbill (Alca torda) Science Article 9 abstract We investigated differences in parent-offspring vocal recognition between males and females in a natural population of razorbills Alca torda, a long-lived and highly social species of auk (Family: Alcidae). Razorbills provide biparental care to their chicks while at the nest site, after which the male is the sole […]