Spring temperatures influence selection on breeding date and the potential for phenological mismatch in a migratory bird

Abstract

Climate change has affected the seasonal phenology of a variety of taxa, including that of migratory birds and their critical food resources. However, whether climate-induced changes in breeding phenology affect individual fitness, and how these changes might, therefore, influence selection on breeding date remain unresolved. Here, we use a 36-year dataset from a long-term, individual-based study of House Wrens (Troglodytes aedon) to test whether the timing of avian breeding seasons is associated with annual changes in temperature, which have increased to a small but significant extent locally since the onset of the study in 1980. Increasing temperature was associated with an advancement of breeding date in the population, as the onset of breeding within years was closely associated with daily spring temperatures. Warmer springs were also associated with a reduced incubation period, but reduced incubation periods were associated with a prolonged duration of nestling provisioning. Nest productivity, in terms of fledgling production, was not associated with temperature, but wetter springs reduced fledging success. Most years were characterized by selection for earlier breeding, but cool and wet years resulted in stabilizing selection on breeding date. Our results indicate that climate change and increasing spring temperatures can affect suites of life-history traits, including selection on breeding date. Increasing temperatures may favor earlier breeding, but the extent to which the phenology of populations might advance may be constrained by reductions in fitness associated with early breeding during cool, wet years. Variability in climatic conditions will, therefore, shape the extent to which seasonal organisms can respond to changes in their environment.

Experimental manipulation of incubation period reveals no apparent costs of incubation in house wrens

“…Average temperature and precipitation at the study site during the month of May is highly variable from year to year, and so too is the average number of fledglings produced per egg (see Figure 1 in Lothery, Thompson, Lawler, & Sakaluk, 2014). April temperatures in 2014 were below the long-term average, and breeding started later than average (see Figure 2 in Bowers et al, 2016); however, during the time that the birds were incubating their clutches (May–June), temperatures were near the average for the 2007–2015 period (see Figure 3 in Bowers et al, 2016). Nevertheless, we cannot rule out the possibility that the absence of a cost of incubation in the present study could be the result of an extraordinarily good year with respect to the amount of food available to the breeding birds.…”

“…These results reinforce previous findings in the study population. Analysis of a 36-year data set revealed strong selection for early breeding, with those females initiating their first clutches earliest in the breeding season producing the highest number of recruits in most years (Bowers et al, 2016). Size-adjusted body mass of nestling house wrens near the time of nest leaving is positively predictive of offspring recruitment and subsequent longevity (Bowers et al, 2014), and so it is not surprising that adult females of higher residual body mass in the current study produced the most descendants over the 3-year study period.…”

Nightjars may adjust breeding phenology to compensate for mismatches between moths and moonlight

“…Thus, later breeding in 2013 could represent a successful trade‐off between the increased risks of harsh weather and the increased opportunities for double brooding that were seen in 2012 (Verboven et al., ). Nonetheless, numerous studies have found that individuals that arrive early have higher reproductive success (McKellar, Marra, & Ratcliffe, ) and that chicks hatched earlier are more likely to survive (Bowers et al., ; Naef‐Daenzer, Widmer, & Nuber, ; Verboven & Visser, ; Verhulst & Tinbergen, ).…”

Variation in the timing of avian egg‐laying in relation to climate

“…Studies of relatively small numbers of species have been conducted in Australia in both marine (Lynch et al 2012, Chambers et al 2014 and terrestrial systems (Gibbs et al 2011, Saunders et al 2016, see Beaumont et al 2015 for a review) showing relationships of breeding and migration to climate. UK and Europe (Crick et al 1997, Mysterud et al 2003, Jiguet et al 2007, Asia (Ge et al 2015, Hua et al 2016, North America (Dickey et al 2008, Bowers et al 2016, and on islands (Wolfe et al 2017)), with many others arising from regions with well collated phenological records such as the northern hemisphere temperate zone (Cockrem 1995, Crick et al 1997, Visser et al 1998. However, none of these Australian studies establishes a baseline understanding of the flexibility of breeding responses to the highly unpredictable climatic conditions experienced across the Australian landscape (Jiang et al 2017).…”

“…In other regions of the globe, studies have quantified these baseline relationships between avian breeding phenology and climate conditions (e.g. UK and Europe (Crick et al 1997, Mysterud et al 2003, Jiguet et al 2007), Asia (Ge et al 2015, Hua et al 2016, North America (Dickey et al 2008, Bowers et al 2016, and on islands (Wolfe et al 2017)), with many others arising from regions with well collated phenological records such as the northern hemisphere temperate zone (Cockrem 1995, Crick et al 1997, Visser et al 1998.…”