Abstract

MARTINEZ GUERRERO, José Hugo et al. Comparative analysis between consecutive winters in grassland sparrow habitat selection: annual rainfall and seed bank. Huitzil [online]. 2022, vol.23, n.2, e640.  Epub Mar 31, 2023. ISSN 1870-7459.  https://doi.org/10.28947/hrmo.2022.23.2.580.

The distribution of resources used by birds directs ecological processes, such as habitat selection. The aim of the present study was to compare in two consecutive winters the habitat selection of grassland sparrows, and to evaluate the influence of annual precipitation and available ground seed biomass. Over two winters we collected seeds from the ground at 45 sites used by Baird’s Sparrow (Centronyx bairdii) and Grasshopper Sparrow (Ammodramus savannarum) and at random sites (n = 45) where no birds were registered. We determined used sites by radio-tracking captured birds fitted with a transmitter. Sites used by sparrows had significantly higher seed biomass than random sites, and this was similar between species. Therefore, the food resource plays an important role in the selection of the winter habitat of the sparrows. In addition, we found a positive correlation between annual precipitation and seed biomass, which is important in a climate change scenario, due to the influence we found on the birds to select wintering sites with higher seed biomass in years with less rainfall. Our results expand the available information on the winter habitat selection of C. bairdii and A. savannarum in Mexico.

Keywords : Ammodramus savannarum; grassland birds; Centronyx bairdii; non-breeding season.

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