Annual chronotypes functionally link life histories and life cycles in birds

Abstract

Life‐history responses to ecological selection pressures can be described by a slow–fast life‐history axis. Along this axis, fast‐living animals usually invest in high breeding output, whereas slow‐living ones prioritize their own survival. Birds may solve the trade‐off between reproduction and survival by optimizing their seasonal schedules. Breeding early tends to facilitate reproductive success, whereas breeding late increases the chances to survive. On the basis of this argument, short‐ and long‐lived birds should benefit from initiating spring activities earlier and later, respectively. The timing of seasonal activities, all else being equal, depends on the architecture of endogenous circannual clocks. Particularly, the length of the circannual period relative to the 365‐day environmental year either facilitates the anticipation of seasonal activities (in case of periods shorter than 365 days) or represents a responsive mode (when periods are longer than 365 days). The two alternatives will be manifested by early or late annual chronotypes, respectively. We hypothesize that in birds, annual chronotype will correspond with position on the “pace‐of‐life scale.” Species with low survival probability, and thus a poor chance of breeding in a next season, should show early annual chronotypes facilitated by circannual‐clock periods shorter than 365 days. In contrast, species with high survival rates should benefit from relatively long circannual periods. We predicted that circannual‐period lengths should correlate positively with species‐specific adult annual survival rates. Using published data for 16 wild bird species, we confirmed the predicted correlation. In our analysis, we accounted for the possible metabolic nature of circannual clocks, a correlation between rate of metabolism and survival, and phylogenetic relationships. On the basis of our finding, we propose that evolutionary responsive circannual clocks help birds cope with temporal variation in the environment in ways that are most appropriate for their life‐history and life‐table attributes. A http://onlinelibrary.wiley.com/doi/10.1111/1365-2435.13181/suppinfo is available for this article.

Misidentification errors in reencounters result in biased estimates of survival probability from CJS models: Evidence and a solution using the robust design

“…To evaluate absolute bias, we first compared the performance of the CJS, RDM and RDMa models with constant parameters across time ( and ) using simulated data with 25 occasions where 25 individual animals were marked at each occasion. We simulated 100 datasets for each of 24 possible permutations of survival () of 0.5 and 0.9 (range of typical survival values in birds, Karagicheva et al, 2018), reencounter () of 0.3, 0.5 and 0.9 and correct identification probabilities () of 0.9, 0.95, 0.99 and 1. The range of reencounter probabilities was chosen based on typical values for the capture–recapture studies, the range of probabilities of correct identification were chosen based on values reported earlier (Schwarz & Stobo, 1999; Tucker et al, 2019) and estimated in the current study.…”

Ecological and behavioural drivers of offspring size in marine teleost fishes

“…For each of the 100 tree topologies in our sample, we ran three MCMC chains for 2.4 × 10 5 iterations, discarded the first 4 × 10 4 iterations as burnin and sampled every 100 iterations, which resulted in effective sample sizes of > 1,500 for all parameters tested per phylogenetic tree. The model outputs were then summarized across all trees following Karagicheva et al (2018). Chain convergence was assessed using the Gelman-Rubin statistic (Gelman & Rubin, 1992), with potential-scale reduction values less than 1.1 for all model outputs.…”

Experimental tests of a seasonally changing visual preference for habitat in a long‐distance migratory shorebird

“…The animals engaging in such long‐distance migrations perform amazing feats of endurance exercise (Piersma, 2011), and navigation (Åkesson & Hedenström, 2007; Mouritsen, 2018; Muheim, 2006; Muheim, Schmaljohann, & Alerstam, 2018; Ritz, Ahmad, Mouritsen, Wiltschko, & Wiltschko, 2010). What seasonal migrants have in common is the circannual steering of relevant physiological processes in relation to navigation (Pinzon‐Rodriguez, Bensch, & Muheim, 2018) and the circannual expression of labile physiological and morphological (“physiomorphic”) traits that facilitate endurance exercise during migration as well as behaviour for survival and reproduction during the appropriate seasons (Bijleveld, 2015; Gwinner, 1996; Karagicheva, Rakhimberdiev, Saveliev, & Piersma, 2018). Physiological preparation for migration in spring is associated with high corticosterone levels (Eikenaar, Klinner, & Stöwe, 2014; Landys‐Ciannelli et al, 2002; Piersma, Reneerkens, & Ramenofsky, 2000), increases in restless behaviour (Gwinner, 1986; Zúñiga et al., 2016) and enhanced cognitive performance (Rattenborg et al., 2004).…”

“…and the circannual expression of labile physiological and morphological ("physiomorphic") traits that facilitate endurance exercise during migration as well as behaviour for survival and reproduction during the appropriate seasons (Bijleveld, 2015;Gwinner, 1996;Karagicheva, Rakhimberdiev, Saveliev, & Piersma, 2018).…”