State and Provincial Checklists

These lists provide information on relative abundance of birds by physiographic strata for states and provinces (for the checklist) or for a location (for the clickable map). The numbers are estimated from Breeding Bird Survey data, and for the checklists they are the mean counts on routes in each physiographic region from the survey averaged over the interval 1982-1996. For the clickable map, the points are distanced-weighted averages of data from nearby routes. So, they represent the number of individuals of the species that you would see in the course of 50 3-min roadside counts (about 2.5 hours intense birding) during an early morning in June.

Note the numbers are rounded to 1 decimal place, except when the number is less than 0.1, in which case it is rounded to 2 decimal places. If fewer than 0.005 birds/route occurred in the region it appears as a 0.00. Do not expect to see those species during a casual birding jaunt!

Relative Abundances from the BBS

These numbers provide a general measure of relative abundance of birds for physiographic strata within states. However, as in all bird surveys based on counts by observers, it is important to recognize that the values can be distorted in several ways:

• Roadside survey bias-Surveys are conducted along roadsides. Species that are not seen along roadsides because they avoid roads or because their habitats are not well represented along roads will not be seen very often by BBS observers.
• Observer differences-Observers tend to count birds in their own (and occasionally idiosyncratic) way. Occasionally, species are misidentified, or an observer will greatly under (or over) count. In trend analyses, we attempt to take these differences into account in the analysis, but that cannot be done when comparing average counts among routes.
• Rare observations-Occasionally, species that do not normally breed in a region show up on a BBS route. These will show up on these lists, but are not a likely observation for an occasional birder.