Time-varying effects of local weather on behavior and probability of breeding deferral in two Arctic-nesting goose populations

Abstract

Arctic-nesting geese face energetic challenges during spring migration, including ecological barriers and weather conditions (e.g., precipitation and temperature), which in long-lived species can lead to a trade-off to defer reproduction in favor of greater survival. We used GPS location and acceleration data collected from 35 greater white-fronted geese of the North American midcontinent and Greenland populations at spring migration stopovers, and novel applications of Bayesian dynamic linear models to test daily effects of minimum temperature and precipitation on energy expenditure (i.e., overall dynamic body acceleration, ODBA) and proportion of time spent feeding (PTF), then examined the daily and additive importance of ODBA and PTF on probability of breeding deferral using stochastic antecedent models. We expected distinct responses in behavior and probability of breeding deferral between and within populations due to differences in stopover area availability. Time-varying coefficients of weather conditions were variable between ODBA and PTF, and often did not show consistent patterns among birds, indicating plasticity in how individuals respond to conditions. An increase in antecedent ODBA was associated with a slightly increased probability of deferral in midcontinent geese but not Greenland geese. Probability of deferral decreased with increased PTF in both populations. We did not detect any differentially important time periods. These results suggest either that movements and behavior throughout spring migration do not explain breeding deferral or that ecological linkages between bird decisions during spring and subsequent breeding deferral were different between populations and across migration but occurred at different time scales than those we examined.

Energetic trade-offs in migration decision-making, reproductive effort and subsequent parental care in a long-distance migratory bird

“…Interestingly, the effects of decision-making (both time spent feeding and energy expenditure) on probability of breeding outcomes did not vary by time interval across spring migration. This is consistent with findings in Cunningham et al [30], who examined the effects of daily decision-making on Greenland white-fronted goose breeding deferrals. We extended this framework to investigate broader intervals that we hypothesized to be of greater ecological importance, but still found similar results.…”

“…We used a training dataset of known white-fronted goose behaviours linked with ACC measurements of those behaviours developed by Cunningham et al . [ 30 ] and VonBank et al . [ 52 ] and methods described in these studies to test a suite of machine learning algorithms from Nathan et al .…”

“…To test hypotheses relating to the effects of weather and habitat use during spring and autumn migration on decision-making, and the effects of decision-making during spring and autumn migration on breeding outcomes and survival, we used ACC data to quantify time spent feeding and overall dynamic body acceleration. We used a training dataset of known white-fronted goose behaviours linked with ACC measurements of those behaviours developed by Cunningham et al [30] and VonBank et al [52] and methods described in these studies to test a suite of machine learning algorithms from Nathan et al [15] for classifying ACC data into behaviour. We used a random forest model (overall accuracy of greater than 95%) to classify all ACC bursts as feeding, flying, stationary or walking, summed the number of ACC fixes classified in each behaviour for each ecologically relevant time interval in spring and autumn migration, and applied the confusion matrix correction for time budgets from Resheff et al [53].…”

“…Greenland white-fronted geese migrate each spring and autumn between breeding areas in west Greenland, staging areas in west and southern Iceland, and wintering areas in Great Britain and Ireland, an annual migration totalling ca 5000 km [24][25][26]. To prepare for two bouts of long-distance migration and breeding, individuals engage in intensive feeding and lower energy expenditure from late winter to the early breeding period [27][28][29][30]. However, preparation may be constrained by environmental conditions at each of these stages.…”

Earlier springs increase goose breeding propensity and nesting success at Arctic but not at temperate latitudes

“…For migratory waterfowl, this relation is often found to be less clear, probably because many species can use a capital strategy, using body stores accumulated on spring staging sites (Ankney & Macinnes, 1978; Gauthier et al., 2003; Jönsson, 1997). In addition to conditions at spring staging sites, conditions encountered during migration are suggested to play an important role for breeding propensity in long‐distance migrants such as Arctic‐breeding geese (Cunningham et al., 2023). Adverse weather conditions en route are known to cause mortality (Loonstra et al., 2019; Newton, 2008), delay arrival at breeding grounds and negatively affect body condition upon arrival (Drent et al., 2006; Lack, 1968; Ma et al., 2011) and can thus carry over to affect breeding propensity.…”