Timing Of Departure Research Articles

Vocal consensus building for collective departures in wild western gorillas.

The ability to coordinate actions is of vital importance for group-living animals, particularly in relation to travel. Groups can only remain cohesive if members possess a cooperative mechanism to overcome differences in individual priorities and social power when coordinating departures. To better understand how hominids achieve spatio-temporally coordinated group movements, we investigated vocally initiated group departures in three habituated groups of western gorillas (Gorilla gorilla) in the Central African Republic. The large sexual dimorphism of gorillas has led to the untested assumption that the silverback males are the sole decision-makers in gorilla groups, although there are also observations that suggest otherwise. To address this, we analysed the direction and timing of group departures and found that high-ranking individuals (silverbacks and high-ranking females) were more successful in indicating the direction of future travel than others, but that the timing of departure was the apparent result of a cumulative vocal voting process among all adult group members. Our findings illustrate that even in species with a large sexual size dimorphism, travel decisions can be taken collectively via a consensus-building process.

Meaningful Results with Limited Resources: Evidence from a Program to Support Graduate Students’ Scholarly Writing

Although writing is an essential skill for graduate students (in and beyond their degree programs), limited programmatic support exists to help students develop mindsets and habits needed to become effective, scholarly writers. Furthermore, attrition rates are on the rise in the U.S., with many students dropping out at the “all but dissertation” stage. The timing of departure indicates writing may be a widespread issue warranting direct intervention. We developed a campus-wide, six-week learning community and certificate program intended to increase students’ self-efficacy in academic writing, using readings, reflection, and discussion among graduate students. Pilot results from 32 participants indicate that a noncredit-bearing, short course can have positive impacts on graduate students’ emotions about writing, their literature management approaches, awareness of the social context of writing, and their understanding of writing resources and academic voice. Potential exists for this low-budget model to be applied more broadly and thereby improve efforts to retain and support graduate students.

The Disavowal of Decisionism: Politically Motivated Exits from the U.S. Courts of Appeals

Abstract The impartiality and apolitical nature of the American judiciary are key to its legitimacy and the liberal constitutional legal system it supports. Though less than 1 % of U.S. Federal judges admit to political motivations for retirement or resignation, our research suggests these influences are more widespread. Examining data from 1802 to 2019, we found 11 % of retirements and 23 % of resignations from the U.S. Courts of Appeals may be linked to political cycles. Judges are less likely to retire before a Presidential election when the President is from a different party than their appointing party, and more likely to resign after the election if the President is from their appointing party. These politically motivated exits have grown, accounting for 14 % of retirements since 1975, which points to a more politically charged and polarized judiciary. Previous studies relying on self-reports or annual analyses have missed these political dynamics in judges’ departure timing. Our quarter-to-election level analysis reveals that significant decisions by Federal judges may often be influenced by unconscious bias or conscious partisan loyalty, both of which challenge the idea of judicial neutrality and the common law precedents judges must uphold. Our findings support growing concerns about undemocratic political power being exercised through the courts, giving rise to juristocracy – the practice of engaging in politics under the guise of legal proceedings.

Control system for automatic adjustment of departure intervals of public transport vehicles

In numerous urban areas, fine-tuning bus schedules to align with fluctuating passenger numbers poses a sizable challenge, compounded by diverse factors such as weather and unexpected events. This paper conducts a comprehensive examination of existing optimization methods aimed at enhancing the departure intervals of public transport systems, particularly focusing on the Bidirectional Coordination Optimization Algorithm (BCOA) and the genetic algorithm. Through systematic analysis, these methodologies are meticulously explored for their effectiveness in addressing the scheduling challenges faced by urban transit systems. Additionally, it delves into specific instances where the Proportional-Integral-Derivative (PID) control mechanism has been employed to adeptly adjust the timing of bus departures based on real-time demand. The PID system's proven reliability and efficacy spotlight its potential as a transformative tool for advancing public transit systems. By leveraging such technology, there's tangible optimism for achieving a more responsive, efficient, and passenger-friendly public transportation network in the years to come.

Redistribution of songbirds within a migratory stopover site as a response to sylviid warbler song playback

Assessing habitat quality is critical for migrating birds, with implications for fuel loading, predation risk and timing of departure. To efficiently distribute within stopover sites, migrants rely on various cues that facilitate habitat quality assessment. In this study, we conducted a playback experiment at a mid‐route stopover site to test the effects of vocal cues, specifically bird songs, on habitat redistribution during spring migration. To estimate the effect of bird songs on bird abundance we mist‐netted and ringed birds for 60 days on alternating playback treatment (playing songs of three sylviid warbler species) and no playback (control) days. A nearby site was used to control for fluctuations caused by migration waves. Overall, total bird abundance was significantly increased by the playback treatment. This increase resulted from the attraction of conspecifics (species whose songs were played) rather than of other species – sylviids or others. Correspondingly, species richness was seemingly unaffected. To investigate the relationship between internal‐state factors and the attraction to playback in the most abundantly attracted species, Eurasian Blackcap Sylvia atricapilla, we tested associations with age, sex and body condition index but found no significant effects, possibly because of the limited sample size. Our findings challenge established ideas regarding heterospecific attraction and contradict previous studies. Attraction to bird song is discussed in the context of geographical location, timing and internal drivers. Vocal cues, specifically bird songs, may affect micro‐habitat selection by migrating songbirds during stopovers. Consequently, we call for consideration of the influence of the acoustic environment on birds during migratory stopover in future studies, habitat management and conservation efforts.

Post-Fledging Movements and Factors that Influence Permanent Departure of Juvenile Crested Caracaras in Florida

ABSTRACT We tracked 48 young Crested Caracaras (Caracara plancus) in south-central Florida from fledging through their first year and sought to define the post-fledging pre-dispersal period and the timing and drivers of permanent departure (PD) from the natal area. By examining Euclidean distances between telemetry locations and the nest for each tagged caracara, we defined the post-fledging dependency period as the first 2 mo after fledging, when fledglings remained mostly within 2.5 km of the nest and were dependent on their parents for food. Before PD, young caracaras explored areas as much as 11 km from their nest but returned to the natal area, resulting in areas used by fledglings up to 6 times the average home range size of an adult breeding pair. Some caracaras remained within their parents’ home range for several months after fledging, even after becoming independent of their parents for food. A fledgling permanently departed its natal area when telemetry indicated it made an abrupt long-distance movement away from its natal area and did not return. We used generalized linear mixed models and a hierarchical modeling approach to test environmental and biological factors that may affect the timing of PD. The most supported model indicated that PD depended on parental reproductive strategy and on the timing of fledging relative to the length of the breeding season. Birds with parents that raised only one brood remained in the natal area for 11.6–21.0 wk longer than birds with parents that raised multiple broods in the same breeding season; fledglings from the first of two broods departed at a younger age, suggesting that the PD decision is partially triggered by the level of parental investment in the first and subsequent brood. Additionally, birds that fledged early in the breeding season departed the natal area 2.8–12.2 wk earlier than those that fledged later in the breeding season, and birds that were exposed to high heat during the nestling stage departed the natal area earlier than those exposed to less heat. The period between fledging and permanent departure from the natal area is important for the conservation of species with delayed dispersal. When developing a conservation strategy for Florida’s caracara population, attention should be paid to protecting areas used by fledglings until PD rather than just focusing on a limited protection zone around the nest.

COORDINATED MANAGEMENT OF AIRCRAFT DEPARTURES TO ENSURE THE SAFETY OF THEIR MOVEMENT AT TRANSPORT HUB

The task is to coordinate the timing of departure from different airports of a large number of aircraft in order to eliminate cases of their dangerous approach in busy transport hub of a group flight. The conflict management function involves reducing the risk of an aircraft colliding with a source of danger to an acceptable level. A conflict situation is any situation involving an aircraft and a source of danger in which existing separation minima may be violated. The formulation of the problem of optimizing the delay time in the departure of aircraft when they approach at transport hubs is formulated and its solution is proposed on the basis of multiplicative convolution according to the criterion of maximum passenger comfort. It is required to form a single criterion for passenger comfort during takeoff and in flight itself, as well as to propose an algorithm for optimizing the departure delay times of a group of aircraft. When assessing comfort, penalty functions for delay in departure, the risk of unsafe approach of ships at transport hubs, and the factor of undesirable maneuvering when changing the flight level and flight speed are taken into account. An algorithm has been developed for the optimal four-alternative assignment of the delay time in the departure of each aircraft, taking into account the parameters of its approach to other aircraft. The examples of calculation and the results of comparing the optimal solution with the known approach are given. A gain has been established in significantly reducing the duration of the “conflict rapprochement”.

Satellite tracking of American Woodcock reveals a gradient of migration strategies

Abstract Diversity in behavior is important for migratory birds in adapting to dynamic environmental and habitat conditions and responding to global change. Migratory behavior can be described by a variety of factors that comprise migration strategies. We characterized variation in migration strategies in American Woodcock (Scolopax minor), a migratory gamebird experiencing long-term population decline, using GPS data from ~300 individuals tracked throughout eastern North America. We classified woodcock migratory movements using a step-length threshold, and calculated characteristics of migration related to distance, path, and stopping events. We then used principal components analysis (PCA) to ordinate variation in migration characteristics along axes that explained different fundamental aspects of migration, and tested effects of body condition, age-sex class, and starting and ending location on PCA results. The PCA did not show evidence for clustering, suggesting a lack of discrete strategies among groups of individuals; rather, woodcock migration strategies existed along continuous gradients driven most heavily by metrics associated with migration distance and duration, departure timing, and stopping behavior. Body condition did not explain variation in migration strategy during the fall or spring, but during spring adult males and young females differed in some characteristics related to migration distance and duration. Starting and ending latitude and longitude, particularly the northernmost point of migration, explained up to 61% of the variation in any one axis of migration strategy. Our results reveal gradients in migration behavior of woodcock, and this variability should increase the resilience of woodcock to future anthropogenic landscape and climate change.

Lunar synchrony, geography, and individual clocks shape autumn migration timing in an avian migrant.

Timing programs in animal migrants have been selected to synchronize movements that coincide with predictable resources on the breeding and nonbreeding grounds. Migrants face potential temporal conflicts if their migration schedules benefit from synchrony to conflicting rhythms associated with annual biogeographical (circannual) cues, lunar (circalunar) cues, or individually repeatable internal clocks. We repeat-tracked individuals of an avian lunaphilic species, Eastern Whip-poor-will (Antrostomus vociferus), for two to three successive autumn migrations to determine the influence of the lunar cycle, breeding location, and individual repeatability on migration timing. Almost all birds avoided departing for migration during a full moon, likely to take advantage of the bright moonlight to facilitate visual foraging and enhance pre-migration fattening. However, groups from two latitudinally distant sampling areas adjusted their autumn departure timing differently relative to the timing of the September full moon, presumably due to differences in seasonal prey availability. Individual repeatability increased throughout autumn migration, suggesting that the factors responsible for shaping migration timing may differ for different migration stages. Our results, that lunar synchrony, local climate, and individual internal clocks appeared to account for much of the variation in migration timing in whip-poor-wills, underscore the value of measuring potentially interacting factors that shape migratory behavior at species, group, and individual levels. It remains unclear if, or how, maintaining individually repeatable annual migration schedules provides an adaptive benefit for whip-poor-wills or other lunaphilic migrants. Further clarifying the reasons for phenotypic variation in whip-poor-will migration timing will improve predictions of their abilities to adjust migratory movements under changing environmental conditions.

Predicting HR Churn with Python and Machine Learning

Employee turnover imposes a substantial financial burden, necessitating proactive retention strategies. The aim is to leverage HR analytics, specifically employing a systematic machine learning approach, to predict the likelihood of active employees leaving the company. Using a systematic approach for supervised classification, the study leverages data on former employees to predict the probability of current employees leaving. Factors such as recruitment costs, sign-on bonuses, and onboarding productivity loss are analysed to explain when and why employees are prone to leave. The project aims to empower companies to take pre-emptive measures for retention. Contributing to HR Analytics, it provides a methodological framework applicable to various machine learning problems, optimizing human resource management, and enhancing overall workforce stability. This research contributes not only to predicting turnover but also proposes policies and strategies derived from the model's results. By understanding the root causes and timing of employee departures, companies can proactively implement measures to mitigate turnover, thereby minimizing the associated financial and operational burdens.

Significantly Earlier Spring Migration in Most Bird Species at the Eastern Limit of Europe.

The first arrival dates of 31 species of migrant birds in the Tatarstan Republic of Russia were monitored for the 34-year period from 1989-2022. Trends in first arrival date were evaluated using regression against the year value. Patterns in arrival data with respect to species traits (habitat, migration distance, body weight, etc.) were evaluated using redundancy analysis. Relationships between first arrival dates and Tatarstan temperatures were also evaluated using regression methods of first-arrival date on monthly mean temperatures. Almost all (28 of 31) species revealed a significantly earlier migration arrival date; however, associations between arrival patterns and species traits were equivocal. Warmer temperatures were significantly associated with earlier arrival in 26 of the 31 species, but the relationship was insufficient to explain the average 11-day advance in species. For these species and in this location only the timing and location of arrival are well recorded; the exact wintering areas and migration routes, and the timing of these phases are less well understood. When these become better known, an investigation of the influence of environmental conditions (including temperature) on departure timing and passage timing and speed is recommended.

Co-migration fidelity at a stopover site increases over time in African-European migratory landbirds.

Migratory species are changing their timing of departure from wintering areas and arrival to breeding sites (i.e. migration phenology) in response to climate change to exploit maximum food availability at higher latitudes and improve their fitness. Despite the impact of changing migration phenology at population and community level, the extent to which individual and species-specific response affects associations among co-migrating species has been seldom explored. By applying temporal co-occurrence network models on 15 years of standardized bird ringing data at a spring stopover site, we show that African-European migratory landbirds tend to migrate in well-defined groups of species with high temporal overlap. Such 'co-migration fidelity' significantly increased over the years and was higher in long-distance (trans-Saharan) than in short-distance (North African) migrants. Our findings suggest non-random patterns of associations in co-migrating species, possibly related to the existence of regulatory mechanisms associated with changing climate conditions and different uses of stopover sites, ultimately influencing the global economy of migration of landbirds in the Palearctic-African migration system.

Spatial and temporal dynamics of a Nassau grouper fish spawning aggregation located on an isolated seamount in Puerto Rico

Abstract The Nassau grouper, Epinephelus striatus, is a slow‐growing, late‐maturing, long‐lived reef fish widely distributed throughout the south‐western North Atlantic. Known for forming large spawning aggregations, numbering tens of thousands, they are now listed as Critically Endangered by the International Union for Conservation of Nature (IUCN). Recently, the only Nassau grouper spawning aggregation in Puerto Rico was documented at Bajo de Sico, a seamount and seasonally closed marine protected area. Studies elsewhere on the spatio‐temporal dynamics of Nassau grouper aggregations have documented how, and how far, fish move from home sites to the spawning site, and have shown the tight link between aggregation formation and the lunar cycle. However, these studies have not evaluated the potential impacts of the reduced spatial extent represented by a seamount, nor have they addressed the impacts of local seasonal protection relative to the size of the closed area and the timing of aggregation formation. Acoustic telemetry was used to quantify the spatio‐temporal dynamics of Nassau grouper spawning aggregation formation at Bajo de Sico. Twenty‐six individuals were tagged and tracked over three consecutive spawning seasons. Nassau grouper formed three or four aggregations per season, corresponding to the lunar cycles from January to April. Individuals displayed high visitation rates to the aggregation site: 98% visited at least two peaks per season; 80% visited multiple seasons. The timing of arrival, departure, and residency at the site were significantly different among individuals and lunar months, indicating significant variability in aggregation formation. Nassau grouper occupied a relatively small staging area (2.7 km2) and courtship arena (0.67 km2) compared with aggregations occurring on continental/insular platforms or large atolls; movements off the seamount may occur but were not detected. Results indicate the current seasonal closure inadequately protects the spawning population on Bajo de Sico and should be extended to the end of June.

Spring arrival of the common cuckoo at breeding grounds is strongly determined by environmental conditions in tropical Africa.

Failure to adapt migration timing to changes in environmental conditions along migration routes and at breeding locations can result in mismatches across trophic levels, as occurs between the brood parasitic common cuckoo Cuculus canorus and its hosts. Using satellite tracking data from 87 male cuckoos across 11 years, we evaluate why the cuckoo has not advanced its arrival to the UK. Across years, breeding ground arrival was primarily determined by timing of departure from stopover in West Africa before northward crossing of the Sahara. Together with high population synchrony and low apparent endogenous control of this event, this suggests that a seasonal ecological constraint operating here limits overall variation in breeding grounds arrival, although this event was itself influenced by carry-over from timing of arrival into tropical Africa. Between-year variation within individuals was, in contrast, mostly determined by northward migration through Europe, probably due to weather conditions. We find evidence of increased mortality risk for (a) early birds following migration periods positively impacting breeding grounds arrival, and (b) late birds, possibly suffering energy limitation, after departure from the breeding grounds. These results help identify areas where demands of responding to global change can potentially be alleviated by improving stopover quality.

Quorum decision making coordinates group departure decisions in Eurasian oystercatchers, Haematopus ostralegus

Prey species that form groups gain a range of benefits from associating with conspecifics, including access to social information. Groups typically coordinate collective movement through local interactions, where individuals copy their nearest neighbours' behaviour to generate group level decisions. However, individuals in a group may not always make ‘correct’ decisions, and blind copying of behaviour can lead to the spread of poor information and maladaptive cascades. To impede the spread of poor information, many animals that form groups have developed information-dampening mechanisms such as consensus decision making through the quorum response. In this study we monitored flocks of roosting Eurasian oystercatchers with a view to understanding the mechanics of group departure decisions and to test for the presence of a quorum response. Nearing high tide, oystercatchers would leave the roosting site en masse, where the timing of departure of many individuals was coordinated. Coordinating the timing of mass departures was a complex task as single birds and small groups frequently joined and departed from the roosting site, meaning individuals had to decide which departures to copy and which to ignore. Individual oystercatchers were more likely to depart within 10 s of another bird if they were closer together in the group, suggesting that departure information may be transferred locally between neighbouring birds. While single departures were very common, most individuals departed in groups of 10 or more, showing that single departures were a relatively weak departure cue and were frequently ignored by the rest of the group. The probability of an individual joining a departure event was higher with increasing departure group size in a nonlinear (sigmoidal) relationship. This trend is consistent with a quorum response with the propensity to copy the departure of groupmates sharply increasing at a quorum threshold of about 10 birds.

Songbirds initiate migratory flights synchronously relative to civil dusk

BackgroundEach spring and fall billions of songbirds depart on nocturnal migrations across the globe. Theory suggests that songbirds should depart on migration shortly after sunset to maximize their potential for nightly flight duration or to time departure with the emergence of celestial cues needed for orientation and navigation. Although captive studies have found that songbirds depart during a narrow window of time after sunset, observational studies have found that wild birds depart later and more asynchronously relative to sunset than predicted.MethodsWe used coded radio tags and automated radio-telemetry to estimate the time that nearly 400 individuals from nine songbird species departed their breeding or wintering grounds across North America. We also assessed whether each species was most likely beginning long-distance migratory flights at departure or instead first making non-migratory regional flights. We then explored variation in nocturnal departure time by post-departure movement type, species, age, sex, and season.ResultsWe found that 90% of individuals from species that were likely initiating long-distance migratory flights departed within 69 min of civil dusk, regardless of species, season, age, or sex. By contrast, species that likely first made non-migratory regional movements away from the migratory destination departed later and more asynchronously throughout the night. Regardless of post-departure movement type, 98% of individuals departed after civil dusk but otherwise showed no preference in relation to twilight phase.ConclusionsAlthough the presence of celestial orientation cues at civil dusk may set a starting point for departure each night, the fact that species likely beginning long-distance migration departed earlier and more synchronously relative to civil dusk than those first making non-migratory regional movements is consistent with the hypothesis that departing promptly after civil dusk functions to maximize the potential for nightly flight duration and distance. By studying the onset of migration, our study provides baseline information about departure decisions that may enhance our understanding of departure timing throughout migration.

Timing of departure from natal areas by golden eagles is not constrained by acquisition of flight skills

The post‐fledging dependence period (PFDP), which extends from a fledgling's first flight out of the nest to its departure from the parents' territory, is crucial in the lifecycle of birds. During this period, juveniles develop their flight and foraging skills to become fully independent. Despite the importance of this life stage in basic bird ecology and conservation, it remains largely overlooked – notably its link with the acquisition of flight skills. In this study, we modeled the variation in seven proxies describing flight skills of 84 GPS‐tracked golden eagle juveniles in France between 2016 and 2020. Juveniles had a long but highly variable PFDP, averaging 177.9 (± 62.2) days after departure from the nest. This period is divided into two phases: a first phase of rapid increase in flight skills over the first 60 days after departure from the nest, followed by a plateau in which flight skills no longer develop until independence. These results suggest that the full development of flight skills is not a constraining factor during the PFDP and that it is advantageous for juveniles to choose to remain in their natal territory. We posit that parents' tolerance of fledged juveniles is a type of parental care that may maximize their own fitness by improving the survival of their descendants. In future studies, it may be of interest to investigate the factors that may explain the high variability in the duration of this stage between individuals within the same population.

Sensory Loss and its Association with Different Types of Departures from the Labor Force Among Older Adults in the US.

To investigate the association between sensory loss and the timing and type of self-reported departures from the labor force, via retirement or disability, we used data from the Health and Retirement Study, cycles 2004-2018. Based on self-reported sensory loss, we classified individuals into four groups: no sensory loss, hearing loss only, vision loss only, and dual sensory loss (vision and hearing loss). We assumed that older adults could leave the labor force either by retirement or due to disability. Because once one type of exit is observed the other type cannot be observed, we implemented a competing risk approach to estimate the instantaneous rate of departure (sub-distribution hazard rate) for leaving the labor force due to disability, treating retirement as a competing risk, and for departures via retirement, with disability as the competing risk. We found that compared to older adults with no sensory loss, adults with vision loss are at a higher risk for leaving the labor force via disability (when treating retirement as a competing risk). Compared to no sensory loss, hearing loss was associated with a higher risk for retirement in models treating disability as a competing risk. Given the differences between disability and retirement benefits (before and after retirement age), policies intended to keep people with sensory loss from early labor force departures, such as accommodations in the workplace and/or hearing and vision care coverage, might contribute to better retiring conditions and healthy aging among older adults with sensory loss.

Local weather and endogenous factors affect the initiation of migration in short‐ and medium‐distance songbird migrants

Migratory birds employ a variety of mechanisms to ensure appropriate timing of migration based on integration of endogenous and exogenous information. The cues to fatten and depart from the non‐breeding area are often linked to exogenous cues such as temperature or precipitation and the endogenous program. Shorter distance migrants should rely heavily on environmental information when initiating migration given relatively close proximity to the breeding area. However, the ability to fatten and subsequently depart may be linked to individual circumstances, including current fuel load and body size. For early and late departing migrants, we investigate effects of temperature, precipitation, lean body mass, fuel load and day of year on the initiation of migration (i.e. fuel load and departure timing) from the non‐breeding region by analyzing 21 years of banding data for four species of short‐ and medium‐distance migrants. Temperatures at the non‐breeding area were related to temperatures at potential stopover areas. Despite local cues being predictive of conditions further north, the amount variation explained by local weather conditions in our models differed by species and temporal period but was low overall (< 33% variation explained). For each species, we also compared lean body mass and fuel load between early and late departing migrants, which showed mixed results. Our combined results suggest that most individuals migrating short or medium distances in our study did not time the initiation of migration with local predictive cues alone, but rather other factors such as lean body mass, fuel load, day of year, which may be a proxy for the endogenous program, and those beyond the scope of our study also influenced the initiation of migration. Our study contributes to understanding which factors influence departure decisions of short‐ and medium‐distance migrants as they transition from the non‐breeding to the migratory phase of the annual cycle.

The risk faced by the early bat: individual plasticity and mortality costs of the timing of spring departure after hibernation

Hibernation is a widespread adaptation in animals to seasonally changing environmental conditions. In the face of global anthropogenic change, information about plastic adjustments to environmental conditions and associated mortality costs are urgently needed to assess population persistence of hibernating species. Here, we used a five‐year data set of 1047 RFID‐tagged individuals from two bat species, Myotis nattereri and Myotis daubentonii that were automatically recorded each time they entered or left a hibernaculum. Because the two species differ in foraging strategy and activity pattern during winter, we expected species–specific responses in the timing of hibernation relative to environmental conditions, as well as different mortality costs of early departure from the hibernaculum in spring. Applying mixed‐effects modelling, we disentangled population‐level and individual‐level plasticity in the timing of departure. To estimate mortality costs of early departure, we used both a capture mark recapture analysis and a novel approach that takes into account individual exposure times to mortality outside the hibernaculum. We found that the timing of departure varied between species as well as among and within individuals, and was plastically adjusted to large‐scale weather conditions as measured by the NAO (North Atlantic Oscillation) index. Individuals of M. nattereri, which can exploit milder temperatures for foraging during winter, tuned departure more closely to the NAO index than individuals of M. daubentonii, which do not hunt during winter. Both analytical approaches used to estimate mortality costs showed that early departing individuals were less likely to survive until the subsequent hibernation period than individuals that departed later. Overall, our study demonstrates that individuals of long‐lived hibernating bat species have the potential to plastically adjust to changing climatic conditions, although the potential for adjustment differs between species.