Article
Local and regional weather patterns influencing post-breeding migration counts of soaring birds at the Strait of Gibraltar, Spain
Ibis
(2016)
Abstract
Migration is a significant event in the annual cycle of many avian species. During migration
birds face many challenges, including unfamiliar foraging and refuge habitats, resulting
in a much higher rate of mortality during migration than during other seasons of the
year. Weather may significantly affect a bird’s decision to initiate migration, the course
and pace of migration, and its survival during migration. Each of these influences may
impact the counts of migrating birds at geographical convergence zones or bottlenecks. It
is important to quantify the effect of short-term weather on these counts to appropriately
interpret and use such counts in other analyses. To this end, we aim to assess the
effects of local and regional weather conditions on the migration counts of soaring birds
at the Strait of Gibraltar during post-breeding migration. We used information-theoretic
approaches to analyse the influence of local weather and weather in northern Spain on
the migration counts of five soaring bird species from two count sites near the Strait of
Gibraltar. Migration counts were higher on days with local northerly and westerly winds,
often following a day of easterly winds, on days with local high pressure systems, and
often following a day of lower pressure. Weather conditions in northern Spain influenced
migration counts at the Strait of Gibraltar, but the effects were much weaker than local
weather conditions. We confirm that short-term weather conditions, locally and regionally,
can influence migration counts and should thus be considered when these counts
are used in other analyses.
Keywords
- atmospheric pressure,
- bottleneck,
- migration,
- migration counts,
- raptors,
- storks,
- wind
Disciplines
Publication Date
2016
DOI
10.1111/ibi.12326
Citation Information
Robert Miller, Alejandro Onrubia, Beatriz Martín, Gregory S. Kaltenecker, et al.. "Local and regional weather patterns influencing post-breeding migration counts of soaring birds at the Strait of Gibraltar, Spain" Ibis Vol. 158 Iss. 1 (2016) p. 106 - 115 Available at: http://works.bepress.com/robert_miller/7/