I dette studiet har jeg undersøkt i hvilken grad lengdefordelingen for 0+ ørret Salmo trutta ved vekstsesongens slutt kan forklares med variasjon i tetthet ( 0+, eller eldre ørret) og ulike miljøvariabler som varierer ...

ABSTRACT Small, isolated and fragmented bird populations are more vulnerable to extinction and studies have shown that they can have a high proportion of unpaired males. Female-biased natal dispersal could be an explanation ...

According to the differential allocation hypothesis, an individual will invest more in an offspring when mated to a high than low qality mate. The blue/green eggshell coluration of pied flycatcher (Ficedula hypoleuca), has ...

This study describes the male and female role in parental care in a Norwegian population of reed buntings (Emberiza schoeniclus). The population has an extensive level of extra-pair young (EPY), with 30% of the offspring ...

Freshwater sculpins and salmonids coexist in many streams throughout the Northern hemisphere, and often constitute an important component of stream ecosystems. Alpine bullhead Cottus poecilopus Heckel have been known to ...

Data from questionnaires filled out by 336 students during a nine day period in January and February 1999 at the University of Oslo, Norway was analyzed to find patterns in gift-giving behavior corresponding to predicted ...

The Red Queen hypothesis states that biological entities rather than abiotic factors constitute the larger part of the selective environment experienced by individual organisms, and that species as a consequence undergo ...

Altricial nestlings hatch at an early stage of development, and depend on their parents to feed them. The quality of the parental care is of great significance to the nestlings fitness and future survival. In the early ...

Ulvens (Canis lupus) områdebruk, døgnrytme og bevegelsesmønster i forhold til menneskelig aktivitet og infrastruktur ble studert i Østfold fylke, 3-6 mil sør for Oslo. Studieområdet er et skog- og jordbruksområde med en ...

Abstract Patterns in time series are observational records of past ecological processes, and identifying these processes remains a major challenge to population ecologists. Until recently, analysis of time series has ...

The presence of gastrointestinal nematodes is considered to be a problem in domestic cattle, and various studies have tried to present reasons for and solutions to this problem. A study was conducted in Southern Norway in ...

We studied a willow warbler (Phylloscopus trochilus) population breeding in Øvre Heimdalen, in Valdres, Norway. Several previous studies have found large differences in the amount of EPY (extra- pair young) in the broods ...

There is considerable controversy regarding the effect of sheep grazing on reindeer populations in Norway. Sheep grazing during summer may affect the critical fall, winter and spring range conditions for reindeer either ...

Recent advances in molecular genetic techniques have made it possible to genotype DNA extracts from non-invasive samples such as hair, faeces, and urine. Subsequent identification of individuals from such material has ...

The feeding behavior is favored by natural selection in the past and is based on getting a high fitness by maximizing net energy intake. Reproductive success among altricial birds is closely related to feeding strategies ...

Abstract Anti-predation behaviour in many rodents has mainly been studied under laboratory conditions, and less in naturally conditions in the field. Here we studied the results of an experiment specifically designed for ...