Data from: February precipitation in the wintering grounds of the lesser whitethroat, Sylvia curruca: is it a cue for migration onset?

Numerous studies report shifts in bird migration phenology, presumably
owing to global warming. However, most studies focus on migration patterns
in the Northern Hemisphere. In this study, we investigated associations
between weather conditions in African wintering grounds of the lesser
whitethroat, Sylvia curruca, and spring arrival time in Eilat, Israel.
Using multivariate regression models, we analysed a 30-year dataset in
order to examine correlations between median springtime arrival and 46
climate variables of the wintering quarters. The model obtained exhibited
a highly statistical fit, involving mean precipitation in February and
March with negative effects and number of wet days during
November–February. February precipitation levels were also the major
factor associated with the interquartile range of arrival time.
Interestingly and contrary to published results, annual or seasonal
precipitation showed no correlation with spring arrival time, nor did
temperature. Moreover, winter in this region falls into dry season with
negligible rainfall quantities. Hence, it is unlikely that precipitation
effect on habitat productivity is a driving force of migration, as
suggested by other studies. Instead, we propose that precipitation in
February acts as a cue for the birds, indicating the approach of spring
and migration time.