The effect of climate change on the duration of avian breeding seasons: a meta-analysis

Abstract

Many bird species are advancing the timing of their egg-laying in response to a warming climate. Little is known, however, of whether this advancement affects the respective length of the breeding seasons. A meta-analysis of 65 long-term studies of 54 species from the Northern Hemisphere has revealed that within the last 45 years an average population has lengthened the season by 1.4 days per decade, which was independent from changes in mean laying dates. Multi-brooded birds have prolonged their seasons by 4 days per decade, while single-brooded have shortened by 2 days. Changes in season lengths covaried with local climate changes: warming was correlated with prolonged seasons in multi-brooded species, but not in single-brooders. This might be a result of higher ecological flexibility of multi-brooded birds, whereas single brooders may have problems with synchronizing their reproduction with the peak of food resources. Sedentary species and short-distance migrants prolonged their breeding seasons more than long-distance migrants, which probably cannot track conditions at their breeding grounds. We conclude that as long as climate warming continues without major changes in ecological conditions, multi-brooded or sedentary species will probably increase their reproductive output, while the opposite effect may occur in single-brooded or migratory birds.

Life‐history innovation to climate change: can single‐brooded migrant birds become multiple breeders?

“…Therefore, we regard the occurrence of these second broods in most cases not as a best‐of‐a‐bad‐job strategy after producing poorly during the first breeding attempt. Indeed, the three Dutch second broods in produced 13 fledglings, of which one (male) recruit was observed as breeder in (average first year recruitment rate is 4%).…”

“…The pied flycatcher is a long‐distance migrant which resides in Europe between April and August (about 5 months), a period used for breeding and moulting. The rest of the year these small insectivorous birds reside in west Africa (about 6 months) or are migrating (about 1 month) (Ouwehand and Both ). Pied flycatchers are most often single brooded, with biparental care.…”

“…The two study populations belong to the earliest laying populations in Europe, and have both advanced laying dates since 1980 (Both et al ). The Drenthe population has been studied since , when we installed 1070 nest boxes in 12 study plots (10–75 ha) across a region of 40 × 20 km in the provinces of Drenthe and Friesland (Both et al ), and increased the number of boxes with an additional 160 in . The number of breeding pairs of pied flycatchers increased from 190 in to around 300 in , and remained fairly stable since then.…”

“…We aimed also to capture the males of these multiple breeding females. When comparing reproductive success of multiple breeding females with the rest of the population, we provide the mean number of fledglings for all broods between and for both populations, and separately for the females that successfully fledged a first brood.…”

Meta‐analyzing the likely cross‐species responses to climate change

“…In a recent meta-analysis, Halupka and Halupka (2017), for example, found that climate change may extend breeding seasons for multibrooded species and reduce it for single-breeding species from the northern hemisphere. We believe that a promising line of investigation would consist in finding other species traits with high capability to predict likely ranges shifts (as forecasted by ENMs).…”