Territory location and quality, together with climate, affect the timing of breeding in the white-throated dipper
Recent climate change has led to advanced spring phenology in many temperate regions. The
phenological response to variation in the local environment, such as the habitat characteristics of the
territories birds occupy, is less clear. The aim of this study is to understand how ecological conditions
affect breeding time, and its consequences for reproduction, in a white-throated dipper Cinclus cinclus
population in a river system in Norway during 34 years (1978–2011). Hatching date advanced almost
nine days, indicating a response to higher temperatures and the advanced phenology in the area. Earlier
breeding was found in warm springs and at lower altitudes. High population density facilitated earlier
breeding close to the coast. Furthermore, when population density was low, breeding was early at
territories that were rarely occupied, while in years with high density, breeding was early at territories
that were frequently occupied. Also, when population density was low, earlier breeding occurred at
territories that on average produced more offspring than other territories, while there was no difference
in breeding time in high population years. Selection for early breeding was dependent on spring
temperatures and high spring temperatures contributed to higher breeding success during the study
period. We found that breeding phenology may have strong effects on fitness in the white-throated
dipper, and thus that breeding time is an important ecological factor in a species that feeds mainly on
aquatic rather than terrestrial prey.
phenological response to variation in the local environment, such as the habitat characteristics of the
territories birds occupy, is less clear. The aim of this study is to understand how ecological conditions
affect breeding time, and its consequences for reproduction, in a white-throated dipper Cinclus cinclus
population in a river system in Norway during 34 years (1978–2011). Hatching date advanced almost
nine days, indicating a response to higher temperatures and the advanced phenology in the area. Earlier
breeding was found in warm springs and at lower altitudes. High population density facilitated earlier
breeding close to the coast. Furthermore, when population density was low, breeding was early at
territories that were rarely occupied, while in years with high density, breeding was early at territories
that were frequently occupied. Also, when population density was low, earlier breeding occurred at
territories that on average produced more offspring than other territories, while there was no difference
in breeding time in high population years. Selection for early breeding was dependent on spring
temperatures and high spring temperatures contributed to higher breeding success during the study
period. We found that breeding phenology may have strong effects on fitness in the white-throated
dipper, and thus that breeding time is an important ecological factor in a species that feeds mainly on
aquatic rather than terrestrial prey.
Publisert i Scientific Reports, 2019
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