Autumn migratory departure is influenced by reproductive timing and weather in an Arctic passerine

Chmura, Helen E.; Krause, Jesse S.; Pérez, Jonathan H.; Ramenofsky, Marilyn; Wingfield, John C.

doi:10.1007/s10336-020-01754-z

Cited by 12 publications

(23 citation statements)

References 97 publications

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“…This pattern reflects the birds' aim to optimise their journey through time and energy savings (Alerstam & Lindström, 1990; Liechti & Bruderer, 1998). Yet, substantial among‐species and among‐individual variability exists with regard to the response of migrating birds to wind conditions (Nilsson, Bäckman & Alerstam, 2014; Chmura et al ., 2020; Packmor et al ., 2020). For instance, Steidinger (1968) reported that nocturnal migration in Switzerland was not inhibited under headwinds and similarly Beason (1978) found that migration intensity in waterbirds was not related to wind direction.…”

Section: Introductionmentioning

confidence: 99%

Understanding the ecological and evolutionary function of stopover in migrating birds

2022

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Global movement patterns of migratory birds illustrate their fascinating physical and physiological abilities to cross continents and oceans. During their voyages, most birds land multiple times to make so-called 'stopovers'. Our current knowledge on the functions of stopover is mainly based on the proximate study of departure decisions. However, such studies are insufficient to gauge fully the ecological and evolutionary functions of stopover. If we study how a focal trait, e.g. changes in energy stores, affects the decision to depart from a stopover without considering the trait(s) that actually caused the bird to land, e.g. unfavourable environmental conditions for flight, we misinterpret the function of the stopover. It is thus important to realise and acknowledge that stopovers have many different functions, and that not every migrant has the same (set of) reasons to stop-over. Additionally, we may obtain contradictory results because the significance of different traits to a migrant is context dependent. For instance, late spring migrants may be more prone to risktaking and depart from a stopover with lower energy stores than early spring migrants. Thus, we neglect that departure decisions are subject to selection to minimise immediate (mortality risk) and/or delayed (low future reproductive output) fitness costs. To alleviate these issues, we first define stopover as an interruption of migratory endurance flight to minimise immediate and/or delayed fitness costs. Second, we review all probable functions of stopover, which include accumulating energy, various forms of physiological recovery and avoiding adverse environmental conditions for flight, and list potential other functions that are less well studied, such as minimising predation, recovery from physical exhaustion and spatiotemporal adjustments to migration. Third, derived from these aspects, we argue for a paradigm shift in stopover ecology research. This includes focusing on why an individual interrupts its migratory flight, which is more likely to identify the individualspecific function(s) of the stopover correctly than departure-decision studies. Moreover, we highlight that the selective forces acting on stopover decisions are context dependent and are expected to differ between, e.g. K−/r-selected species, the sexes and migration strategies. For example, all else being equal, r-selected species (low survival rate, high reproductive rate) should have a stronger urge to continue the migratory endurance flight or resume migration from a stopover because the potential increase in immediate fitness costs suffered from a flight is offset by the expected higher reproductive success in the subsequent breeding season. Finally, we propose to focus less on proximate mechanisms controlling landing and departure decisions, and more on ultimate mechanisms to identify the selective forces shaping stopover decisions. Our ideas are not limited to birds but can be applied to any migratory species. Our revised definition of stopover and the proposed paradigm shi...

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Section: Introductionmentioning

confidence: 99%

Understanding the ecological and evolutionary function of stopover in migrating birds

2022

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“…organisms that actively maintain relatively constant body temperatures through metabolic heat production). Several studies have highlighted the indirect effects of warming on Arctic wildlife, such as compositional shifts in the prey base ( Gaston and Hipfner, 1998 ; Gaston et al, 2005 ; Yurkowski et al, 2018 ), earlier breeding phenology and shifts in the timing of migration ( Chmura et al, 2020 ; Clairbaux et al, 2019 ; Le Corre et al, 2017 ). In contrast, the direct effects of warming on the physiology and behaviour of Arctic endotherms has been observed but less studied ( Gaston et al, 2002 ).…”

Section: Introductionmentioning

confidence: 99%

Limited heat tolerance in a cold-adapted seabird: implications of a warming Arctic

Choy

O’Connor

Gilchrist

et al. 2021

Journal of Experimental Biology

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The Arctic is warming at approximately twice the global rate, with well-documented indirect effects on wildlife. However, few studies have examined the direct effects of warming temperatures on Arctic wildlife, leaving the importance of heat stress unclear. Here, we assessed the direct effects of increasing air temperatures on the physiology of thick-billed murres (Uria lomvia), an Arctic seabird with reported mortalities due to heat stress while nesting on sun-exposed cliffs. We used flow-through respirometry to measure the response of body temperature, resting metabolic rate, evaporative water loss and evaporative cooling efficiency (the ratio of evaporative heat loss to metabolic heat production) in murres while experimentally increasing air temperature. Murres had limited heat tolerance, exhibiting: (1) a low maximum body temperature (43.3°C); (2) a moderate increase in resting metabolic rate relative that within their thermoneutral zone (1.57 times); (3) a small increase in evaporative water loss rate relative that within their thermoneutral zone (1.26 times); and (4) a low maximum evaporative cooling efficiency (0.33). Moreover, evaporative cooling efficiency decreased with increasing air temperature, suggesting murres were producing heat at a faster rate than they were dissipating it. Larger murres also had a higher rate of increase in resting metabolic rate and a lower rate of increase in evaporative water loss than smaller murres; therefore, evaporative cooling efficiency declined with increasing body mass. As a cold-adapted bird, murres' limited heat tolerance likely explains their mortality on warm days. Direct effects of overheating on Arctic wildlife may be an important but under-reported impact of climate change.

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“…Migration phenology is ultimately controlled by endogenous time-keeping mechanisms [ 22 , 23 ], but it can be proximately modified by intrinsic and extrinsic factors including sex, age, body condition, and weather [ 24 – 26 ]. Presumably these factors act in a hierarchical fashion, with sex and age narrowing the window for the beginning of migration prior to the effects of shorter-term changes in body condition and day-to-day variation in weather.…”

Section: Introductionmentioning

confidence: 99%

“…Studying departure decisions made by individual birds has resulted in more variable conclusions about the role of weather when compared to radar studies. Many individual tracking studies have documented increased departure probability with supporting winds [ 38 – 40 ], while others have shown no effect of wind [ 41 – 43 ], variable effects of wind [ 44 , 45 ], or increased departure probability with headwinds [ 26 ]. Similarly, although several studies have found that birds are more likely to depart on nights when atmospheric pressure is high and/or rising [ 26 , 44 , 46 , 47 ], and with little cloud cover [ 37 , 45 , 48 ], others have found no or variable effects of pressure [ 37 , 40 ] and cloud cover [ 44 , 49 ].…”

Section: Introductionmentioning

confidence: 99%

“…Many individual tracking studies have documented increased departure probability with supporting winds [ 38 – 40 ], while others have shown no effect of wind [ 41 – 43 ], variable effects of wind [ 44 , 45 ], or increased departure probability with headwinds [ 26 ]. Similarly, although several studies have found that birds are more likely to depart on nights when atmospheric pressure is high and/or rising [ 26 , 44 , 46 , 47 ], and with little cloud cover [ 37 , 45 , 48 ], others have found no or variable effects of pressure [ 37 , 40 ] and cloud cover [ 44 , 49 ]. By contrast, the effect of rainfall has been more consistent with several studies showing that departure probability increases on nights with little to no precipitation [ 26 , 44 , 45 , 48 ].…”

Section: Introductionmentioning

confidence: 99%

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Atmospheric pressure predicts probability of departure for migratory songbirds

et al. 2023

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Background Weather can have both delayed and immediate impacts on animal populations, and species have evolved behavioral adaptions to respond to weather conditions. Weather has long been hypothesized to affect the timing and intensity of avian migration, and radar studies have demonstrated strong correlations between weather and broad-scale migration patterns. How weather affects individual decisions about the initiation of migratory flights, particularly at the beginning of migration, remains uncertain. Methods Here, we combine automated radio telemetry data from four species of songbirds collected at five breeding and wintering sites in North America with hourly weather data from a global weather model. We use these data to determine how wind profit, atmospheric pressure, precipitation, and cloud cover affect probability of departure from breeding and wintering sites. Results We found that the probability of departure was related to changes in atmospheric pressure, almost completely regardless of species, season, or location. Individuals were more likely to depart on nights when atmospheric pressure had been rising over the past 24 h, which is predictive of fair weather over the next several days. By contrast, wind profit, precipitation, and cloud cover were each only informative predictors of departure probability in a single species. Conclusions Our results suggest that individual birds actively use weather information to inform decision-making regarding the initiation of departure from the breeding and wintering grounds. We propose that birds likely choose which date to depart on migration in a hierarchical fashion with weather not influencing decision-making until after the departure window has already been narrowed down by other ultimate and proximate factors.

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Autumn migratory departure is influenced by reproductive timing and weather in an Arctic passerine

Cited by 12 publications

References 97 publications

Understanding the ecological and evolutionary function of stopover in migrating birds

Understanding the ecological and evolutionary function of stopover in migrating birds

Limited heat tolerance in a cold-adapted seabird: implications of a warming Arctic

Atmospheric pressure predicts probability of departure for migratory songbirds

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