CHRISTMAS BIRD COUNT

What Was Measured?
Shown here are the number of species identified and total numbers of birds counted by the trained observers during the Sequoia Audubon Society's Christmas bird count at Año Nuevo and Crystal Springs.  In addition, the counts for five bird species, associated with different ecosystems, are shown.

Why It Is Important?
Birds perform many functions within ecosystems including prey and predator functions, pollination and pest control.

The number and diversity of birds can indicate the health of the ecosystem.  Strong and consistent numbers indicate an ecosystem in balance.  However, with migratory birds, the rise and fall in numbers may be related to problems elsewhere in their migratory range.

For focus, we have chosen key indicator species for specific ecosystems.  This includes the American crow, a species that is known to increase in habitat that has been degraded.

What Was Found?
The number of species identified at both sites remains fairly consistent and comparable with between 150 and 200 species identified at each site.  However, in most years, five times as many individuals are counted at Crystal Springs.  In addition, the Crystal Springs site has a greater deviation in the number of individual birds counted.

What Is The Trend?
There is no standard, other than past records, against which these numbers can be measured.  The county's bird count cannot be easily compared with other areas because of the marked differences in natural conditions.

Though the populations of the individual species show various cyclical patterns, no clear patterns are identified.  However, the population of the American crow at Crystal Springs seems to be increasing.

Source: Sequoia Audubon Society

Researcher: Julia Bott