Litter and seed burying alter food availability and foraging efficiency of granivorous birds in the Monte desert.

CUETO VR, FA MILESI & L MARONE

JOURNAL OF AVIAN BIOLOGY

WILEY-BLACKWELL PUBLISHING, INC

Año: 2013 vol. 44 p. 339 - 346

0908-8857

We determined experimentally if the main granivorous bird species that feed on the ground in the central Monte desert are able to detect and consume seeds buried in the soil or trapped within litter. A better understanding of seed vulnerability to birds would allow a better translation from seed abundance into seed availability, a necessary step to assess seed limitation scenarios, and whether birds can alter the distribution of soil seeds through their consumption. Rufous-collared Sparrow found and consumed high proportions of buried seeds, although less seeds were eaten at increasing depths. In contrast, Many-colored Chaco-Finch, Common Diuca-Finch and Cinnamon Warbling-Finch did not find buried seeds. All bird species fed on every substrate offered: As a whole, birds reduced 50% seed consumption in Prosopis litter, and 30% in Larrea litter, compared to consumption in bare soil. This effect was less notable for Rufous-collared Sparrow, which has the option to ?double scratch?, a behavioral ability that contributes to its great diet breath and abundance in Monte desert. Like birds do not reach a fraction of seeds buried and trapped by litter, seeds readily available for them may be scarcer than previously estimated. Further, like the four bird species detect and consume seeds from littered microhabitats, seed consumption by them surely affect the seasonal dynamics of the soil seed bank in all microhabitat types of the Monte desert.