Fledging Mass Is Color Morph Specific and Affects Local Recruitment in a Wild Bird.

AbstractEarly-life conditions may have long-lasting effects on life history. In color polymorphic species, morph-specific sensitivity to environmental conditions may lead to differential fitness. In tawny owls (), pheomelanin-based color polymorphism is expected to be maintained because the brown morph has higher adult fitness in warmer environments, while selection favors the gray morph under colder conditions.

Pale and dark morphs of tawny owls show different patterns of telomere dynamics in relation to disease status.

Parasites are expected to exert long-term costs on host fecundity and longevity. Understanding the consequences of heritable polymorphic variation in disease defence in wild populations is essential in order to predict evolutionary responses to changes in disease risk. Telomeres have been found to shorten faster in malaria-diseased individuals compared with healthy ones with negative effects on longevity and thereby fitness.

Clutch size of a vole-eating bird of prey as an indicator of vole abundance.

Voles are often considered as harmful pests in agriculture and silviculture. Then, the knowledge of their abundance may be of considerable economical importance. Commonly used methods in the monitoring of vole abundances are relatively laborious, expensive, and spatially quite restricted.

Climate change drives microevolution in a wild bird.

To ensure long-term persistence, organisms must adapt to climate change, but an evolutionary response to a quantified selection pressure driven by climate change has not been empirically demonstrated in a wild population. Here, we show that pheomelanin-based plumage colouration in tawny owls is a highly heritable trait, consistent with a simple Mendelian pattern of brown (dark) dominance over grey (pale). We show that strong viability selection against the brown morph occurs, but only under snow-rich winters.

Population dynamics in a cyclic environment: consequences of cyclic food abundance on tawny owl reproduction and survival.

1. Understanding which factors regulate population dynamics may help us to understand how a population would respond to environmental change, and why some populations are declining. 2.

The colour of fitness: plumage coloration and lifetime reproductive success in the tawny owl.

We studied variation in plumage colour and life history in a population of tawny owls (Strix aluco) in southern Finland, using 26 years of data on individually marked male and female owls. Colour was scored on a semi-continuous scale from pale grey to reddish brown. Colour scoring was repeatable and showed a bimodal distribution (grey and brown morph) in both sexes.