Different responses to cold weather in two pied flycatcher populations

Abstract

We compared how breeding parameters differ according to prevailing weather conditions between a marginal, subarctic (69°N) and temperate (61°N) population of the pied flycatcher Ficedula hypoleuca, a small migratory insectivorous passerine. We predicted that the effects of weather on breeding performance (clutch size, hatching success, nestling growth, fledging success) would be greater at northern latitudes, where the weather conditions are more extreme and unpredictable. We found that the breeding parameters, except clutch size, were not, however, inferior in the north. Northern birds, unlike the southern ones, responded to colder conditions by laying smaller clutches and maintaining a larger energy reserve (indicated by higher female body mass and higher levels of subcutaneous fat). If a cold spell occurred during the nestling period, southern flycatchers had 5–10% lower fledging success than the northern ones. Our results indicate that in the north, the breeding individuals coped with cold and variable weather better than the individuals in the southern population. This could be adaptive, because at high latitudes there is a higher probability of cold weather at the time of breeding.

The importance of microclimate variation in determining size, growth and survival of avian offspring: experimental evidence from a cavity nesting passerine

“…Their study also showed that growth was affected indirectly by ambient temperature through its effects on abundance of aerial insects. Similarly, Eeva et al (2002) found that although ambient temperature influenced mass growth in both temperate and sub-arctic breeding populations of pied flycatchers (Ficedula hypoleuca), there were no systematic differences between the two areas despite large differences in ambient temperature. They concluded that birds breeding in colder climates were adapted to the low temperatures that occurred there, whereas birds breeding in more southerly areas lacked such adaptations because they rarely encountered extremes in temperatures.…”

Asociación entre distribución continental y regional. Análisis con la avifauna forestal y de medios arbolados de la península Ibérica

“…Así, Thomas et al (2001) no encuentran que la mayor temperatura que sufre una población insular de Parus caeruleus que habita una localidad muy cáli-da de Córcega afecte a un marcado incremento en el balance hídrico (pérdida de agua por evaporación) de pollos y adultos reproductores, o que introduzca cambios fisiológicos como manifestación de adaptaciones locales a condiciones muy térmicas. Por otro lado, Eeva et al (2002) no encuentran en el límite septentrional de distribución de Ficedula hypoleuca que los cambios de temperatura entre una localidad templada (61º N) y otra subártica (69º N) afecten a parámetros de éxito reproductivo, aunque las poblaciones septentrionales soportaban mejor las olas de frío durante la reproducción que las meridionales.…”

Geographical Variation in Egg Mass and Egg Content in a Passerine Bird

“…The study species shows geographical variation in reproductive traits: Timing of breeding gets later and clutch size decreases towards the north, where breeding seasons are shorter and more unpredictable, temperatures are lower and food availability during egg-laying may be more limited (as egg laying begins at earlier ambient phenology) [15], [49]–[52]. Egg size has been found to increase (linear or quadratic trends) towards the north in other European passerines [53], [54], but trends in the pied flycatcher are unclear [55].…”