Effects of extreme thermal conditions on plasticity in breeding phenology and double-broodedness of Great Tits and Blue Tits in central Poland in 2013 and 2014

Abstract

Many avian species in Europe breed earlier as a result of higher temperatures caused by global climate changes. Climate change means not only higher temperatures but also more frequent extreme weather events, sometimes contrasting with the long-term trends. It was suggested that we should look closely at every extreme phenomenon and its consequences for the phenology of organisms. Examining the limits of phenotypic plasticity may be an important goal for future research. Extremely low spring temperatures in 2013 (coldest spring in 40 years) resulted in birds laying unusually late, and it was followed in 2014 by the earliest breeding season on record (warmest spring in 40 years). Here, we present results concerning breeding phenology and double-broodedness in the Great Tit (Parus major) and the Blue Tit (Cyanistes caeruleus) in 2013 and 2014 in an urban parkland and a deciduous forest in central Poland. Great Tits started laying eggs 18.2 days later in 2013 than in 2014 in the parkland, whereas the analogous difference was 21.1 days in the forest. Blue Tits started laying eggs in the parkland 18.5 days later in 2013 than in 2014, while the analogous difference was 21.6 days in the forest. The difference in the proportion of second clutches in Great Tits between 2013 (fewer second clutches) and 2014 (more second clutches) was highly significant in the parkland and in the forest. This rather large extent of breeding plasticity has developed in reaction to challenges of irregular inter-annual variability of climatic conditions. Such a buffer of plasticity may be sufficient for Blue Tits and Great Tits to adjust the timing of breeding to the upcoming climate changes.

Hatching delays in great tits and blue tits in response to an extreme cold spell: a long-term study

“…The great tit and the blue tit are among such earlier breeding species (Bauer et al 2010). Our previous studies show that extreme phenomena may act in opposition to general trends (Glądalski et al 2014, 2016a)—the generally warmer and earlier springs do not exclude spells of exceptionally unfavorable weather occasionally. In the present study, hatching delays of great tits and blue tits were highly correlated with temperatures during the mid-laying-early-incubating period.…”

“…Clutch initiation date in tits is characterized by wide phenotypic plasticity and it largely depends on the temperatures directly before the laying of the first egg. The moment of initiating a clutch by a single tit female may differ more than 3 weeks between breeding seasons depending on the temperatures (Glądalski et al 2014, 2016a; Wesołowski et al 2016) but also on the habitat type (Blondel et al 1993; Massa et al 2011). When the temperatures are appropriate, females start producing eggs (in tits one per day) and then, if there is a sudden temperature drop, they may delay the moment of laying the next eggs or delay the moment of starting incubation.…”

“…In addition to variation in local weather conditions, the occurrence of extreme weather events also affects breeding birds (Jenouvrier 2013; Mainwaring et al 2017). A cold snap during the breeding season may have large consequences for breeding birds (Glądalski et al 2014, 2016a; Indykiewicz 2015; Tobolka et al 2015). On the other hand, it was suggested that the recent extreme weather events can be treated as natural experiments that may elucidate the mechanisms by which birds adjust their phenology to fluctuating environments (Both and Visser 2005; Jentsch et al 2007; Glądalski et al 2016a; Altwegg et al 2017).…”

“…A cold snap during the breeding season may have large consequences for breeding birds (Glądalski et al 2014, 2016a; Indykiewicz 2015; Tobolka et al 2015). On the other hand, it was suggested that the recent extreme weather events can be treated as natural experiments that may elucidate the mechanisms by which birds adjust their phenology to fluctuating environments (Both and Visser 2005; Jentsch et al 2007; Glądalski et al 2016a; Altwegg et al 2017). Fletcher et al (2013) and Whitehouse et al (2013) conclude that there is a need to collect long-term phenology monitoring data in order to fully understand the impacts of climate change on different species.…”

Two amphibian species in the urban environment: changes in the occurrence, spawning phenology and adult condition of common and green toads

“…a longer breeding season by 6 days was observed. In the area of the city where the climate should be warmer and more stable, we can expect that the differences in phenology between the seasons will be lower, as urban conditions may accelerate breeding, especially during extreme weather events when spring is delayed (Glądalski et al 2016). Similar data are not available for other urban areas, so it is difficult to compare them with other results, and there are no data for amphibian phenology from cities and rural areas, as there are for other vertebrates such as birds (e.g.…”