the current population number and trend. In absence of annual population counts, we used SABAP2 presence-absence data \citep{Brooks2020} to estimate a Bayesian dynamic extension of a Royle-Nichols model \citep{Royle2003,Altwegg_2019,Rossman_2016} . Our data consists of a number of sites (i.e. pentads) that are sampled each year several times and in each visit the presence or absence of the species of interest is recorded. The number sites and the number of visits to each site may change from year to year. In each year, we selected only those sites that were visited at least five times to have sufficient data to estimates the probability of detection with confidence.