Effect of climatic change on the duration of the breeding season in three European thrushes

Abstract

Capsule Evidence for extension of breeding seasons in Song Thrushes and Blackbirds (multiple-brooded species) and shortening in Fieldfares (a single-brooded species). Aims To analyse breeding data from central Europe during 1964-2006 in relation to climatic conditions operating at breeding and wintering grounds, and to compare breeding phenology in urban and rural habitats. Methods Using chick ringing data we evaluated long-term changes in breeding phenology of Fieldfares Turdus pilaris, Song Thrushes T. philomelos and Common Blackbirds T. merula . Changes in phenology were analysed for the 5th percentile, median, 95th percentile, inter-quantile range (IQR) and brood size. Results All thrushes showed consistent trends towards earlier onset of breeding. However, there was a contrasting pattern in the later phenological characteristics (median, 95th percentile and IQR) that were associated with single-versus multiple-brooded species. The single-brooded Fieldfares revealed an advancing trend in all phenological phases, which caused shortening of its breeding period. In contrast, the multiple-brooded Song Thrushes and Blackbirds delayed both medians and the 95th percentiles of breeding dates leading to extension of their breeding seasons. Temperatures at both wintering and breeding grounds were generally negatively associated with the onset of breeding. Urban birds bred significantly earlier than their rural conspecifics, but brood sizes did not differ. Conclusion Multiple-brooded species may respond differently to increasing spring temperatures than single-brooded species.

The effect of climate change on laying dates, clutch size and productivity of Eurasian Coots Fulica atra

“…As nest card data are subject to bias introduced by variable sampling efforts (Weidinger 2001 ), for each year we estimated 5th and 95th percentiles of the first-egg dates, following other authors analysing laying trends from nest-card records (e.g. Najmanová and Adamík 2009 ). Likewise, the interval between these dates was an estimation of the season length (c.f.…”

“…Changes in laying dates may also affect the duration of the entire breeding season, leading to its shortening or extension (reviewed by Halupka and Halupka 2017 ), and in turn may affect changes in offspring productivity. In particular, shortening of breeding season has been found in single-brooded species, frequently relying on single food resources (Drever and Clark 2007 ; Najmanová and Adamík 2009 ). In contrast, many double-brooded species have extended their seasons in response to climate change.…”

Challenging claims in the study of migratory birds and climate change

“…In general, flexibility in timing is expected to relate inversely to migratory distance and body size (Hedenström, 2006, 2008), as well as to the number and spacing of stages and substages in the annual cycle (Wingfield, 2008). Climate change may affect the latter, for instance by earlier arrival allowing extra clutches or more time between clutches (Møller, 2007 a ; Najmanová & Adamík, 2009; Møller et al , 2010 a ). On the other hand, ontogenetic effects on the timing of migration are also little explored.…”

Individual fitness and the effects of a changing climate on the cessation and length of the breeding period using a 34‐year study of a temperate songbird

“…We predicted that the cessation of breeding would depend, in part, on abiotic factors like those linked to the initiation of breeding (Gullett et al, 2013;Jacobs, Reader, & Fair, 2013;Reed, Jenouvrier, & Visser, 2013), such as the availability, timing, and quality of food, breeding sites, or other limiting resources (Arcese & Smith, 1988;Gullett et al, 2013;Matthysen, Adriaensen, & Dhondt, 2011;Reale, Mcadam, Boutin, & Berteaux, 2003;Van Noordwijk, Mccleery, & Perrins, 1995). However, empirical results are contradictory on the effect of temperature and precipitation on the cessation of breeding by individual females in many taxa (Chase, Nur, & Geupel, 2005;Gullett et al, 2013;Halupka, Dyrcz, & Borowiec, 2008;Husby, Kruuk, & Visser, 2009;Jacobs et al, 2013;Mcdermott & Degroote, 2016;Najmanova & Adamik, 2009;Rutschmann et al, 2016;Shine & Brown, 2008;Sinclair, SaR, & Arcese, 2000;Tokolyi, Schmidt, & Barta, 2014;Wells et al, 2016). In addition, it is well-known that breeding density and the traits of individuals can also influence the probability of multiparity and cessation of breeding (Eccard & Ylonen, 2003;Jankowiak & Wysocki, 2016;Leips & Travis, 1999;Nelson, Agrell, Erlinge, & Sandell, 1991;Reed et al, 2013;Williams, Lane, Humphries, Mcadam, & Boutin, 2014).…”