Monitoring Canadian bird populations with winter counts

Abstract

Two winter bird surveys in Canada have range-wide population monitoring potential: Christmas Bird Counts (CBCs) and Project FeederWatch (PFW). CBC trends are shown to be correlated to Breeding Bird Survey (BBS) trends, whether or not part of the winter range lies outside the CBC coverage area. Some species are poorly covered by this survey (e.g. seabirds, nocturnal species, and Neotropical migrants). Only eight Canadian breeding species that are not sampled by the BBS have their winter range well-covered by the CBC, but the CBC should be valuable as an independent source of trend data for many more species, including northern nesters with only marginal BBS coverage. More work is needed to show whether PFW trends match BBS trends; even if they do, PFW covers relatively few species, and most are monitored already by the BBS and/or CBC