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 […]
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 […]
Population fluctuations of Siskins Carduelis spinus,Common Crossbills Loxia curvirostra, and Citril FinchesCarduelis citrinella in relationship to flowering intensityof spruce Picea abies
Red Crossbill (Loxia curvirostra) Science Article 2 abstract Annual population abundances from 1992 to 2002 of Siskins Carduelis spinus, CommonCrossbills Loxia curvirostra and Citril Finches Carduelis citrinella were studied in relationto flowering intensity of spruce Picea abies.We used point countmethod to study thechanges in abundance of the three species in the Northern Black Forest (southwest […]
Is the nominate subspecies of the Common Crossbill Loxia c. curvirostra polytypic? I. Morphological differences among years at a single site.
Red Crossbill (Loxia curvirostra) Science Article 1 abstract The discovery of discrete vocal types of Common Crossbill in Western Europe opens the possibility that the nominate subspecies Loxia c. curvirostra in fact consists of a group of cryptic, vocally differentiated and reproductively isolated sibling species, reflecting a similar situation in North America. We compared measures […]
Sexing Razorbills Alca torda breeding at Machias Seal Island, New Brunswick, Canada, using discriminant function analysis.
Razorbill (Alca torda) Science Article 5 abstract In 2000 and 2001, we determined the sex of 80 adult Razorbills Alca torda caught on Machias Seal Island, New Brunswick, Canada, 71 birds in 2000 and 9 in 2001. Sex was determined for the 2000 birds using DNA from feathers, and for the 2001 captures using behavioural […]
Age at First Return and Breeding of Razorbills (Alca torda)on theGannet Islands, Labrador and Machias Seal Island, New Brunswick
Razorbill (Alca torda) Science Article 11 abstract Resightings of Razorbills (Alca torda) banded as chicks on the Gannet Islands, Labrador (N = 1,873resightings of 638 individuals) and Machias Seal Island, New Brunswick JENNIFER L. LAVERS, Waterbirds 31(1): 30-34, 2008 Download article download full text (pdf)
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 […]
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, […]
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 […]
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 […]