Sökning: "laying date"

Visar resultat 1 - 5 av 8 avhandlingar innehållade orden laying date.

1. 1. Nesting and migration in the introduced Canada goose in Sweden

   Författare :Göran Sjöberg; Catherine M. Lessells; Umeå universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; Species introductions; DNA fingerprinting; natal dispersal; breeding dispersal; bird migration; wintering areas; clutch size; laying date; body reserves; nest defence; waterfowl; Canada goose; Anatidae; Branta canadensis;

   Sammanfattning : The aim of the thesis was to document patterns in breeding and migration in Swedish Canada geese Branta canadensis, to explain these against the genetic and historical background of the population, and to test predictions of hypotheses pertaining to parental investment.The Canada goose population in Sweden was founded by the introduction of a few individuals in the 1930's. LÄS MER

3. 2. Costs, benefits and constraints in the evolution of avian reproductive tactics: a study on the blue tit

   Författare :Erik Svensson; Evolutionär ekologi; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; reproductive timing; selection analysis; natural selection; mate quality; nestlings; sex ratio; DNA-content; flow cytometry; ELISA; BMR; energetics; immunocompetence; immune system; sexual conflict; nestling mortality; thermoregulation; moult; reproductive costs; reproductive effort; Parus caeruleus; blue tit; birds; juvenile survival; laying date; food supply; Animal ecology; Djurekologi;

   Sammanfattning : In this study I have investigated the various factors influencing reproductive tactics among breeding blue tits (Parus caeruleus). The study was carried out in a nestbox-breeding population of marked individuals at the Revinge Area, outside Lund, southern Sweden. LÄS MER

4. 3. Causes and consequences of quantitative trait variation for reproductive performance in hole nesting birds

   Författare :Robert Przybylo; Uppsala universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Ecology; timing of breeding; climate change; parental and territorial quality; morphology; sexual size dimorphism; intersexual niche differentiation; Ekologi; Terrestrial; freshwater and marine ecology; Terrestisk; limnisk och marin ekologi; Animal Ecology; zooekologi;

   Sammanfattning : This thesis examines the causes and consequences of environmental variability and individual morphological differences on breeding success and survival in three hole nesting birds.An analysis of directional and stabilising natural selection in Collared Flycatchers (Ficedula albicollis) suggested that forces of selection acting on quantitative traits are weak and cannot explain the observed sexual size dimorphism (SSD) in this species. LÄS MER

5. 4. Life History of the Common Gull (Larus canus) : A Long-Term Individual-Based Study

   Författare :Kalev Rattiste; Mats Björklund; Jon E Brommer; Jan-Åke Nilsson; Uppsala universitet; []
   Nyckelord :Ecology; longitudinal studies; reproductive success; survival; pair bond; indicator trait; breeding time; heritability; selection; Ekologi; Larus canus; ekologisk botanik; Ecological Botany;

   Sammanfattning : An individual’s life history is a sequence of events which eventually determine its contribution to the next generation, or fitness. These events are affected by environmental factors, genetic make-up and decisions made by an individual and its breeding partner. LÄS MER

7. 5. Costs and Tactics in the Evolution of Reproductive Effort

   Författare :Ingemar Jönsson; Biologiska institutionen; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; capital breeding; Falco tinnunculus; body mass; DEE; reproductive effort; reproductive costs; income breeding; Animal ecology; Djurekologi;

   Sammanfattning : This study focuses on various aspects of costs of reproduction and the evolution of energetic breeding tactics. It emphasizes the distinction between demographic costs of reproduction expressed already before current offspring have reached independence (prebreeding costs), and costs expressed only after offspring independence (postbreeding costs). LÄS MER