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 […]
Category: Charadriiformes
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 […]
Population structure and origins of Purple Sandpipers Calidris maritima in north Norway during winter
Purple Sandpiper (Calidris maritima) Science Article 2 abstract Wintering Purple Sandpipers Calidris maritima were captured at Varangerfjorden, Finnmark, in March 1992, and compared with samples from Troms county in November 1988 to describe the population structure in north Norway in terms of age and sex classes, and to determine the origins of these wintering birds. […]
How do Purple Sandpipers Calidris maritima survive the winter north of the Arctic circle?
Purple Sandpiper (Calidris maritima) Science Article 1 abstract Winter north of the Arctic circle in northern Norway is colder, windier and there is less solar radiation than in eastern Scotland, at a latitude 13degree further south. We predicted from equations derived from heated taxidermic mounts that the maintenance metabolism (Basal Metabolic Rate plus extra costs […]
The incidence of nonbreeding by adult Great Skuas and Parasitic Jaegers from Foula, Shetland
Pomarine Skua (Stercorarius pomarinus) Science Article 1 abstract Several recent studies of seabirds have found high levels of nonbreeding by experienced adults. By contrast, just 8.9% (range 4-14%) of experienced Great Skuas (Catharacta skua) on Foula, Shetland Islands, deferred breeding between 1989-1996. For Parasitic Jaegers (Stercorarius parasiticus), a corresponding value of 5.5% (range 3-8%) was […]
Conservation management of Lapwing Vanellus vanellus on lowland arable farmland in the UK
Northern Lapwing (Vanellus vanellus) Science Article 7 abstract Lapwing Vanellus vanellus is known to be declining throughout much of its UK breeding range. The ecological requirements of the species are well known and a variety of mechanisms exist which can be implemented to help recovery. Arable options within agri-environment schemes can be used to provide […]
Chick punishmenat ndc hicka doptionin NorthernLapwing
Northern Lapwing (Vanellus vanellus) Science Article 10 abstract In Northern Lapwings Vanellus vanellus female-female aggression is common in polygynous ma-tings (Liker & Szekely 1997, G. B. Gr0nst0limpubi.), and leads to discrete female territorieswithin the territories of polygynous males (J. E. Hafs-mo unpubl.). Female territories are maintainedthroughout the chick-rearing period Byrkjedal, I. et al., Ornis Fenn. […]