Doi: https://doi.org/10.13157/arla.71.2.2024.ra5
Authors: Juan ARIZAGA and Óscar GORDO
E-mail: jarizaga@aranzadi.eus
Published: Volume 71.2, July 2024. Pages 291-306.
Language: English
Keywords: bird migration, coastal marshes, fuel deposition rate, fuel load, population dynamics, Spain and stopover ecology
Summary:
Understanding the dynamics of stopover site quality and the adaptive response of birds within these contexts is essential for comprehending migratory strategies and their impact on individual survival and fitness. To investigate these dynamics, we examined 16 years of bluethroat Luscinia svecica monitoring at Txingudi, one of its key stopover sites in northern Iberia. Our aim was to examine annual variations and potential temporal trends in demographic structure (characterised by subspecies, age and sex ratios), population size, timing of passage, stopover duration, fuel load and fuel deposition rate. Such variations could signal a shift in the ecological value of this stopover site. the number of Bluethroats declined at an annual rate of 2.3%. Stopover probability and body mass varied annually, the latter showing a negative trend. However, population structure, passage timing and fuel deposition rate remained remarkably constant, with only minor deviations from the mean in specific years for certain parameters. The observed population decline mirrored that in the breeding population in France, suggesting changes in major stopover sites like -Txingudi may reflect dynamics within breeding areas. Future research, including comparative studies across flyways, will be essential for comprehension of the long-term temporal dynamics of major stopover site usage.
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