Breeding bird survey

[2] Future plans for the BBS include expanding coverage in central and western North America, and adding routes in northern Mexico.

The surveys conducted by BBS take place during the peak of the nesting season; usually June, but also May in regions with warmer temperatures.

[1] BBS data is quite difficult to analyze given that the survey does not produce a complete counting of the breeding bird populations but more like a relative abundance index.

[1] When analyzed at larger scales, the relative abundance maps can offer a clear indication of the status and distribution of bird species that are observed by the BBS.

The RSPB BBS coordinates over 3200 active routes, with more than 3000 birders involved in monitoring the population trends of more than 100 bird species.