Assessing the role of multiple environmental factors on Eurasian Spoonbill departure decisions from stopover sites
2010 (English)In: Ardea, ISSN 0373-2266, Vol. 98, no 1, 3-12 p.Article in journal (Refereed) Published
Understanding the factors driving departure decisions from stopover sites is critical when predicting the dynamics of bird migration. We investigated the interactive effects of wind, tidal characteristics, and precipitation on the departure decisions of the Eurasian Spoonbill Platalea I. leucorodia from a major coastal stopover locality in northern Iberia. Most departing Spoonbills (>80%) crossed an adjacent mountain range to follow a direct route over inland Iberia, while the remainder made a detour following an indirect coastal route along the coast of the Iberian Peninsula. During four consecutive autumns, we daily monitored departing Spoonbills leaving along these two routes. The birds taking the inland route, crossing unsuitable habitats and needing therefore higher fuel-loads, departed preferentially under favourable tailwind conditions (TWC). This represented a significant increase in distance covered and/or a decrease in energy spent per unit time. Moreover, Spoonbills taking the inland route often departed during spring tides. For the indirect coastal route, TWC did not affect the onset of migration but bird departures increased with neap tides. Precipitation and date were negatively correlated with departures towards both routes, whereas Spoonbill density at the stopover had a positive effect. Our findings provide empirical support for the role that wind assistance may play for Spoonbills to resume migration.
Place, publisher, year, edition, pages
2010. Vol. 98, no 1, 3-12 p.
departure decisions, ecological barriers, migratory strategies, Spoonbill, tides, waterbirds, wind assistance
IdentifiersURN: urn:nbn:se:uu:diva-136323ISI: 000277095500002OAI: oai:DiVA.org:uu-136323DiVA: diva2:376945