Staging ecology of black-tailed godwits in Portuguese rice fields and correlations with breeding season events

PhD ceremony: Mr. P.M.G. Lourenço, 16.15 uur, Academiegebouw, Broerstraat 5, Groningen

Thesis: Staging ecology of black-tailed godwits in Portuguese rice fields and correlations with breeding season events

Promotor(s): prof. T. Piersma

Faculty: Mathematics and Natural Sciences

 

Continental black-tailed godwits Limosa limosa limosa stage in the rice fields of Iberia during migration between West Africa and Northern Europe. Pedro Lourenço proposes some management guidelines to ensure the conservation of this critical staging area for black-tailed godwits, as well as favour the local bird community: keeping part of the rice fields flooded in winter, phasing ploughing activities along the winter and including the most important rice field areas for godwits in the local protected areas. A total of 53000-59000 birds use each year the rice fields around the estuaries of the Tejo and Sado rivers, Portugal (representing roughly 40% of the flyway population now estimated to count 135000-140000 birds). Individuals stay in the area for an average 22-25 days. These birds forage on rice seeds; preferring rice fields that are flooded and that have already been ploughed, which have the highest rice abundances. Godwit flocks deplete the rice fields during their staging period, but move to new fields, made available by farmers ploughing the fields, as soon as the intake rates fall below the necessary levels for body maintenance. The timing of the staging period is not correlated to the timing of breeding season events, nor to breeding success correlates. This fact, and the good feeding conditions found by godwits in Portugal suggest this step of the migration is not contributing to the ongoing decline of this globally near-threatened species. Still, changes in farming practices and a reduction in the rice farmed area may pose threats in the long-term.