Comparison of Total Species Recorded Annually on Regional Christmas Bird Counts and Great Backyard Bird Counts

The total number of species recorded on the collective Christmas Bird Counts (CBCs) of the Upper Cumberland Region appears to have reached a plateau sometime prior to the winter of 2003-2004, because the range of total species recorded from the winter of 2003-2004 to the winter of 2007-2008 was quite compressed (109-113).  However, total species recorded during the Regional Pooled Data Event of the Great Backyard Bird Count (GBBC) during the same five-year period increased in a roughly linear manner from the winter of 2003-2004 when 74 species were recorded to the winter of 2007-2008 when 105 species were recorded, suggesting that the level of effort needed for the GBBC effort to roughly match the CBC effort in terms of species recorded per annual event had been nearly attained by the latter winter--with the caveat that the number of species available to be recorded during late winter (GBBC) is assumed to be slightly fewer than the number of species available to be recorded during early winter (CBC) because the number of late-lingering migrants present during early winter (CBC) probably exceeds the number of early arriving migrants present during late winter (GBBC).

Table 1. Total Species recorded on collective annual CBCs and collective annual GBBCs in the UCR.

    To access the Central Nodes for the Regional CBC data or the Regional GBBC data, click on one of these links:

• Central Node for CBCs in the UCR
• Central Node for GBBCs in the UCR