Counterintuitive roles of experience and weather on migratory performance

Rus, Adrian I.; Duerr, Adam E.; Miller, Tricia A.; Belthoff, James R.; Katzner, Todd E.

doi:10.1642/auk-16-147.1

Cited by 23 publications

(34 citation statements)

References 30 publications

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“…Although plausible, this hypothesis is not supported by other data. For example, analysis of sex and capture locations of > 80 eagles trapped from 2006 to 2018 in eastern North America (Miller et al , Rus et al ) provides little evidence for sex‐based segregation in wintering areas.…”

Section: Discussionmentioning

confidence: 99%

Spatial and temporal patterns in age structure of Golden Eagles wintering in eastern North America

et al. 2020

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The behavior of wildlife varies seasonally, and that variation can have substantial demographic consequences. This is especially true for long‐distance migrants where the use of landscapes varies by season and, sometimes, age cohort. We tested the hypothesis that distributional patterns of Golden Eagles (Aquila chrysaetos) wintering in eastern North America are age‐structured (i.e., birds of similar ages winter together) through the analysis of 370,307 images collected by motion‐sensitive trail cameras set over bait during the winters of 2012–2013 and 2013–2014. At nine sites with sufficient data for analysis, we documented 145 eagle visits in 2012–2013 and 146 in 2013–2014. We found significant between‐year variation in age structure of wintering eastern Golden Eagles, driven largely by annual differences in the proportion of first‐winter birds. However, although many other species show spatial structure in wintering behavior, our analysis revealed no latitudinal organization among age cohorts of wintering eastern Golden Eagles. The lack of age‐related latitudinal segregation in wintering behavior does not exclude the possibility that these eagles have sex‐based or other types of dominance hierarchies that could result in spatial or temporal segregation. Alternatively, other mechanisms such as food availability or habitat structure may determine the distribution and abundance of Golden Eagles in winter.

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Section: Discussionmentioning

confidence: 99%

Spatial and temporal patterns in age structure of Golden Eagles wintering in eastern North America

et al. 2020

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“…Several studies show that the seasonal and regional differences in the hourly or daily ground speeds of soaring migrants are strongly influenced by atmospheric conditions (Shamoun-Baranes et al 2003a; Mellone et al 2012, 2015; Vansteelant et al 2015; Rus et al 2017), rather than by seasonal differences in the motivation to minimize travel time. How soaring migrants adjust their airspeeds to weather conditions is less clear.…”

Section: Individual Responsementioning

confidence: 99%

Atmospheric conditions create freeways, detours and tailbacks for migrating birds

2017

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The extraordinary adaptations of birds to contend with atmospheric conditions during their migratory flights have captivated ecologists for decades. During the 21st century technological advances have sparked a revival of research into the influence of weather on migrating birds. Using biologging technology, flight behaviour is measured across entire flyways, weather radar networks quantify large-scale migratory fluxes, citizen scientists gather observations of migrant birds and mechanistic models are used to simulate migration in dynamic aerial environments. In this review, we first introduce the most relevant microscale, mesoscale and synoptic scale atmospheric phenomena from the point of view of a migrating bird. We then provide an overview of the individual responses of migrant birds (when, where and how to fly) in relation to these phenomena. We explore the cumulative impact of individual responses to weather during migration, and the consequences thereof for populations and migratory systems. In general, individual birds seem to have a much more flexible response to weather than previously thought, but we also note similarities in migratory behaviour across taxa. We propose various avenues for future research through which we expect to derive more fundamental insights into the influence of weather on the evolution of migratory behaviour and the life-history, population dynamics and species distributions of migrant birds.

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“…, Rus et al . ). Such efficiency can be from in‐flight improvements or, as suggested by this work, by changes to the amount of time birds spend in flight.…”

Section: Discussionmentioning

confidence: 97%

“…We then calculated hourly speeds from these data (in km/h) by dividing the total distance travelled by Eagles by the total duration (Rus et al . ). We classified the bird as either ‘moving’, when average speed over the entire hour was ≥ 0.05 km/h, or ‘not moving’, when average speed was < 0.05 km/h.…”

Section: Methodsmentioning

confidence: 97%

Relevance of individual and environmental drivers of movement of Golden Eagles

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Duerr²,

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et al. 2019

Ibis

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An animal's movement is expected to be governed by an interplay between goals determined by its internal state and energetic costs associated with navigating through the external environment. Understanding this ecological process is challenging when an animal moves in two dimensions and even more difficult for birds that move in a third dimension. To understand the dynamic interaction between the internal state of an animal and the variable external environment, we evaluated hypotheses explaining association of different covariates of movement and the trade‐offs birds face as they make behavioural decisions in a fluctuating landscape. We used ~870 000 GPS telemetry data points collected from 68 Golden Eagles Aquila chrysaetos to test demographic, diel, topographic and meteorological hypotheses to determine (1) the probability that these birds would be in motion and (2), once in motion, their flight speed. A complex and sometimes interacting set of potential internal and external factors determined movement behaviour. There was good evidence that reproductive state, manifested as age, sex and seasonal effects, had a significant influence on the probability of being in motion and, to a lesser extent, on speed of motion. Likewise, movement responses to the external environment were often unexpectedly strong. These responses, to northness of slope, strength of orographic updraft and intensity of solar radiation, were regionally and temporally variable. In contrast to previous work showing the role of a single environmental factor in determining movement decisions, our analyses support the hypothesis that multiple factors simultaneously interact to influence animal movement. In particular they highlighted how movement is influenced by the interaction between the individual's internal reproductive state and the external environment, and that, of the environmental factors, topographic influences are often more relevant than meteorological influences in determining patterns of flight behaviour. Further disentangling of how these internal and externals states jointly affect movement will provide additional insights into the energetic costs of movement and benefits associated with achieving process‐driven goals.

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Counterintuitive roles of experience and weather on migratory performance

Cited by 23 publications

References 30 publications

Spatial and temporal patterns in age structure of Golden Eagles wintering in eastern North America

Spatial and temporal patterns in age structure of Golden Eagles wintering in eastern North America

Atmospheric conditions create freeways, detours and tailbacks for migrating birds

Relevance of individual and environmental drivers of movement of Golden Eagles

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