Climate change, breeding date and nestling diet: how temperature differentially affects seasonal changes in pied flycatcher diet depending on habitat variation

Abstract

Summary 1.Climate warming has led to shifts in the seasonal timing of species. These shifts can differ across trophic levels, and as a result, predator phenology can get out of synchrony with prey phenology. This can have major consequences for predators such as population declines owing to low reproductive success. However, such trophic interactions are likely to differ between habitats, resulting in differential susceptibility of populations to increases in spring temperatures. A mismatch between breeding phenology and food abundance might be mitigated by dietary changes, but few studies have investigated this phenomenon. Here, we present data on nestling diets of nine different populations of pied flycatchers Ficedula hypoleuca, across their breeding range. This species has been shown to adjust its breeding phenology to local climate change, but sometimes insufficiently relative to the phenology of their presumed major prey: Lepidoptera larvae. In spring, such larvae have a pronounced peak in oak habitats, but to a much lesser extent in coniferous and other deciduous habitats. 2. We found strong seasonal declines in the proportions of caterpillars in the diet only for oak habitats, and not for the other forest types. The seasonal decline in oak habitats was most strongly observed in warmer years, indicating that potential mismatches were stronger in warmer years. However, in coniferous and other habitats, no such effect of spring temperature was found. 3. Chicks reached somewhat higher weights in broods provided with higher proportions of caterpillars, supporting the notion that caterpillars are an important food source and that the temporal match with the caterpillar peak may represent an important component of reproductive success. 4. We suggest that pied flycatchers breeding in oak habitats have greater need to adjust timing of breeding to rising spring temperatures, because of the strong seasonality in their food. Such between-habitat differences can have important consequences for population dynamics and should be taken into account in studies on phenotypic plasticity and adaptation to climate change.

Adaptation of timing of life history traits and population dynamic responses to climate change in spatially structured populations

“…For example, several species breed either in oak habitats, where caterpillars exist in great abundance during a short time period during spring or in coniferous habitats with lower and later caterpillar abundance peaks Blondel 2007;Veen et al 2010). The resource phenology in coniferous habitats seems relatively constant while the resource peak in oak habitats is correlated with spring temperature Burger et al 2012), which is in line with one of our assumed scenarios of change (scenario 3, Fig. 2).…”

Earlier breeding, lower success: does the spatial scale of climatic conditions matter in a migratory passerine bird?

“…Insufficient advancement of laying date relative to the phenological advancement of prey species has been associated with reduced fledging success in various insectivorous bird species (e.g., Burger et al. 2012; Reed et al. 2013).…”

Fire‐stimulated reproduction in the resprouting, non‐serotinous conifer Podocarpus drouynianus (Podocarpaceae): the impact of a changing fire regime

“…We used PQL for the model fits due to considerable overdispersion within the count data (Bolker et al 2009). Analysis was conducted using the glmmPQL function within the 'MASS' package (Venables and Ripley 2002) is presented to provide a clear overview of the impact of main factors on seed production following Burger et al (2012) who also used glmmPQL to fit overdispersed ecological data. Mean seed weight between burn season (pooled by study site) for material collected during the 2012 census was compared using a t test, assuming unequal variance.…”