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Birds move because of internal factors such as for defense or to obtain food, yet the environment the animal experiences also drives movement. Researchers studied trade-offs golden eagles face as they make movement decisions by examining factors such as age and sex, topographic and meteorological data, and time of day.

A complex and sometimes interacting set of internal and external factors determined movement behavior. 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 features in the external environment such as updraft strength and solar radiation intensity, were strong. An important finding was that topographic influences were often more relevant than meteorological influences in determining patterns of flight behavior. Their findings form a framework for further refining scientific understanding of the ecology of soaring birds and animal movement.


Sur, M., Duerr, A.E., Bell, D.A., Fisher, R.N., Tracey, J.A., Bloom, P.H., Miller, T., Katzner, T.E., 2019, Relevance of individual and environmental drivers of movement of Golden Eagles: Ibis,

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