Mass or pace? Seasonal energy management in wintering boreal passerines

Research output: Contribution to journalArticle

Abstract

Research on winter energy management in small vertebrates has focused on the regulation of body mass (BM) within a framework of starvation-predation trade-off. Winter-acclimatized birds exhibit a seasonal increase in both BM and basal metabolic rate (BMR), although the patterns of co-variation between the two traits remain unknown. We studied this co-variation in three different species of wild titmice, great, blue and willow tits, originating from two boreal regions at different latitudes. Seasonal change in BM and BMR was inter-dependent, particularly in the great tit; however, by contrast, no seasonal change was observed in the willow tit. BMR changed non-linearly in concert with BM with a peak in midwinter for both blue and great tits, whereas such non-linear pattern in willow tit was opposite and independent of BM. Surprisingly, BMR appears to be more sensitive to ambient temperatures than BM in all three species studied. Energy management is a multifaceted strategy that cannot be fully understood without considering reserve levels and energy expenditure simultaneously. Thus, our study indicates that the prevailing conceptual framework based on variation in BM alone is insufficient to understand seasonal energy management in small wintering passerines.

Details

Authors
Organisations
External organisations
  • CSIC Estación Biológica de Doñana (EBD)
  • University of Oulu
Research areas and keywords

Subject classification (UKÄ) – MANDATORY

  • Evolutionary Biology

Keywords

  • Basal metabolic rate, Optimal body mass theory, Parus, Phenotypic integration, Winter ecology
Original languageEnglish
JournalOecologia
Publication statusE-pub ahead of print - 2019 Jan 7
Publication categoryResearch
Peer-reviewedYes