Effects of rainfall on bird reproduction in a semi-arid Neotropical region

Abstract

In semi-arid ecosystems, birds commonly use rainfall as a reliable environmental cue to adjust the timing and strength of their reproductive activity. Here we evaluate this hypothesis for a community of birds in the Caatinga (the semi-arid region of northeastern Brazil), using brood patch information and nest abundance. Sampling occurred every 14 days between September 2012 and August 2013 (brood patch), and every three or four days during the reproductive period (nests). Abundance of brood patches and nests were correlated, and all brood patches were recorded between March and July (4.5 to 5.0 months). We recorded three peaks of brood patch abundance: the first 28 days after the first rains, the second 14 days after the second rainfall peak, and the third synchronously with the third rainy period. These results indicate that intra-annual variation in local rainfall has the potential to account for variations in the timing and intensity of reproduction in the studied birds.