Groping in the Fog: Soaring Migrants Exhibit Wider Scatter in Flight Directions and Respond Differently to Wind Under Low Visibility Conditions

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Version: Final published version
License: CC BY 4.0
Serval ID
serval:BIB_426F118F3004
Type
Article: article from journal or magazin.
Collection
Publications
Institution
Title
Groping in the Fog: Soaring Migrants Exhibit Wider Scatter in Flight Directions and Respond Differently to Wind Under Low Visibility Conditions
Journal
Frontiers in Ecology and Evolution
Author(s)
Becciu Paolo, Panuccio Michele, Dell'Omo Giacomo, Sapir Nir
ISSN
2296-701X
Publication state
Published
Issued date
29/10/2021
Volume
9
Language
english
Abstract
Atmospheric conditions are known to affect flight propensity, behaviour during flight, and migration route in birds. Yet, the effects of fog have only rarely been studied although they could disrupt orientation and hamper flight. Fog could limit the visibility of migrating birds such that they might not be able to detect landmarks that guide them during their journey. Soaring migrants modulate their flight speed and direction in relation to the wind vector to optimise the cost of transport. Consequently, landmark-based orientation, as well as adjustments of flight speed and direction in relation to wind conditions, could be jeopardised when flying in fog. Using a radar system operated in a migration bottleneck (Strait of Messina, Italy), we studied the behaviour of soaring birds under variable wind and fog conditions over two consecutive springs (2016 and 2017), discovering that migrating birds exhibited a wider scatter of flight directions and responded differently to wind under fog conditions. Birds flying through fog deviated more from the mean migration direction and increased their speed with increasing crosswinds. In addition, airspeed and groundspeed increased in the direction of the crosswind, causing the individuals to drift laterally. Our findings represent the first quantitative empirical evidence of flight behaviour changes when birds migrate through fog and explain why low visibility conditions could risk their migration journey.
Keywords
Ecology, Ecology, Evolution, Behavior and Systematics
Web of science
Open Access
Yes
Create date
06/12/2021 9:57
Last modification date
07/12/2021 7:09
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