Changes in breeding phenology and population size of birds

• Published in: The Journal of animal ecology Vol. 83; no. 3; pp. 729 - 739
• Main Authors: Dunn, Peter O, Møller, Anders P, Griffith, Simon
• Format: Journal Article
• Language: English
• Published: Oxford University Press 01.05.2014; John Wiley & Sons Ltd; Blackwell; Blackwell Publishing Ltd
• Subjects: Animal and plant ecology; Animal ecology; Animal Migration; Animal populations; Animal reproduction; Animal, plant and microbial ecology; Animals; Aves; Biological and medical sciences; Birds; Birds - physiology; Breeding; breeding season; Breeding seasons; Climate Change; Climate ecology; Climatology. Bioclimatology. Climate change; Clutch size; correlation; duration of breeding season; Earth, ocean, space; Ecological life histories; Europe; Exact sciences and technology; External geophysics; Fundamental and applied biological sciences. Psychology; General aspects; habitats; life history; Meteorology; migration; mismatch hypothesis; Models, Biological; oviposition; Phenology; Population Density; Population dynamics; Population size; Population trends; progeny; Reproduction; Seasons; temporal variation; Vertebrates: general zoology, morphology, phylogeny, systematics, cytogenetics, geographical distribution; North America; Europe; Breeding season; Migration; Duration; birds; Dynamical climatology; Climate change; Vertebrata; Reproduction; Population survey; mismatch hypothesis; Phenology; population trends; duration of breeding season; Aves; migration; climate change
• ISSN: 0021-8790; 1365-2656
• DOI: 10.1111/1365-2656.12162

Although the phenology of numerous organisms has advanced significantly in response to recent climate change, the life‐history and population consequences of earlier reproduction remain poorly understood. We analysed extensive data on temporal change in laying date and clutch size of birds from Europe and North America to test whether these changes were related to recent trends in population size. Across studies, laying date advanced significantly, while clutch size did not change. However, within populations, changes in laying date and clutch size were positively correlated, implying that species which advanced their laying date the most were also those that increased their clutch size the most. Greater advances in laying date were associated with species that had multiple broods per season, lived in nonagricultural habitats and were herbivorous or predatory. The duration of the breeding season increased for multibrooded species and decreased for single‐brooded species. Changes in laying date and clutch size were not related to changes in population size (for resident or migratory species). This suggests that, across a wide variety of species, mismatches in the timing of egg laying or numbers of offspring have had relatively little influence on population size compared with other aspects of phenology and life history.