In-flight turbulence benefits soaring birds

The Auk
By: , and 

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Abstract

Birds use atmospheric updrafts to subsidize soaring flight. We observed highly variable soaring flight by Black Vultures (Coragyps atratus) and Turkey Vultures (Cathartes aura) in Virginia, USA, that was inconsistent with published descriptions of terrestrial avian flight. Birds engaging in this behavior regularly deviated vertically and horizontally from linear flight paths. We observed the soaring flight behavior of these 2 species to understand why they soar in this manner and when this behavior occurs. Vultures used this type of soaring mainly at low altitudes (<50 m), along forest edges, and when conditions were poor for thermal development. Because of the tortuous nature of this flight, we describe it as “contorted soaring.” The primary air movement suitable to subsidize flight at this altitude and under these atmospheric conditions is small-scale, shear-induced turbulence, which our results suggest can be an important resource for soaring birds because it permits continuous subsidized flight when other types of updraft are not available.

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Additional publication details

Publication type Article
Publication Subtype Journal Article
Title In-flight turbulence benefits soaring birds
Series title The Auk
DOI 10.1642/AUK-15-114.1
Volume 133
Issue 1
Year Published 2016
Language English
Publisher American Ornithological Society
Contributing office(s) Forest and Rangeland Ecosystem Science Center
Description 7 p.
First page 79
Last page 85
Country United States
State Virginia
Online Only (Y/N) N
Additional Online Files (Y/N) N