Comparison of Total Species Recorded Annually during Regional Christmas Bird Counts and during Pooled Data Events of Great Backyard Bird Count

A species of the Region's open habitats, Horned Larks often begin to sing territorially as early as the time of the Great Backyard Bird Count or just following it, as was the case for this individual, whose image was captured on Student's Home Rd., DeKalb County, Tennessee; photo Judy C. Fuson (27 February 2010).

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 2008–2009 was quite compressed (109–113)—although the total (121) for CBCs conducted during the winter of 2009–2010 surpassed the high end of that range.

    Total species recorded during the Regional Pooled Data Event (PDE) of the Great Backyard Bird Count (GBBC) during the same 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 PDE of 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 (PDE of the 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 (PDE of the GBBC).  Note that the species totals for PDEs of the GBBCs conducted during the winters of 2008–2009 and 2009–2010 were somewhat lower than the high total achieved during the winter of 2007–2008.

    Comparison of species totals for these events is useful as a way of seeing how the winter birdlife of the Region changes from early to late winter.  At the continental level, having large sets of bird data for early and late winter should also allow better determination of trends in bird populations than having only the early set of data.  See the Preliminary Regional Bird-Monitoring Plan for the known or suspected Regional status of many species:

• Regional Bird-Monitoring Plan

Table 1. Total Species recorded on collective annual CBCs and collective annual Pooled Data Events of GBBC 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

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