Site-specific observation in the breeding season improves the ability of checklist data to track population trends

Checklist programs that compile birding observations are potentially useful for population monitoring. Previous analyses showed that trends in Quebec checklist data from migration seasons were significantly correlated With tr ends front the Breeding Bird Survey (BBS) in Quebec, although agreement of trend magnitudes for individual species was low. Here we analyze Quebec che cklist data from the breeding season for comparison, using both the full da ta set and a subset of data collected at frequently visited ("standard") si tes. Checklist trends from the breeding season For standard sites correspon ded much more closely to magnitudes of BBS trends than checklist trends bas ed on all sites, although in both cases, checklists accurately reflected di rection of BBS trend in >80% of species. Checklist trends from migration se asons for all sites and for standard sites were similar to each other. and did not correspond as well to BBS trends, probably because different popula tions were sampled in the two seasons. Checklist programs can be improved f or population monitoring purposes by encouraging frequent reporting front s tandard sites, and by collecting recommended ancillary data that allow anal ysts to select data most appropriate to their research questions.