Recent tools for population abundance estimation adjustment and their use in long-term French red-legged partridge survey

Abstract

The consistency of population estimates is crucial for long term surveys, especially for conservation and management purposes, and particularly for game species as the red-legged partridge Alectoris rufa. Most monitoring programs simply assume that count indexes are proportionally related to abundance. However, this assumption cannot be made when detection varies spatially and temporally, as it is mostly the case. Advances of statistical tools allow now detection modeling using spatially and temporally repeated count data and lead to less-biased estimates than raw counts, and sometimes to less effort in the field. In the future, they might become highly relevant for monitoring programs; however field biologists might have to be trained or assisted for data modeling. We illustrate the case of the French survey of red-legged partridge populations (Alectoris rufa), the method being also used for the survey of a northern Italian population.