© Tejon Ranch Conservancy 2013
Citizen Scientists make important contributions to the Conservancy’s Science Program. First and foremost we can utilize
the knowledge and passion of interested experts to document and better understand the natural resources of Tejon
Ranch. Citizen science activities also provide a directed form of public access to the Ranch. We have been fortunate to
host many outstanding citizen scientists, and in particular the North American Field Herping Association, Kern Chapter of
the California Native Plant Society and multiple Audubon chapters have become important partners. Some of our Citizen
Science projects are described below.
Christmas Bird Count
The Christmas Bird Count (CBC) is a census of birds in the Western Hemisphere, performed annually by volunteer
birdwatchers, and organized and compiled by National Audubon Society. Before the turn of the 20th century, people
engaged in a holiday tradition known as the Christmas "Side Hunt." They would choose sides, go into the field with their
guns, and whoever killed the biggest pile of birds and other animals won. Beginning on Christmas Day 1900, ornithologist
Frank Chapman, an early officer in the then fledgling Audubon Society, proposed a new holiday tradition-a "Christmas
Bird Census"-that would count birds rather than hunt them. This has grown to be the largest citizen science endeavor in
the Western Hemisphere.
Count volunteers follow specified routes through a designated 15-mile (24-km) diameter circle, counting every bird they
see or hear all day. A map of the Tejon Ranch count circle (CATJ) can be found here. All birds are counted all day, giving
an indication of the total number of birds in the circle that day. All individual CBC's are conducted in the period from
December 14 to January 5 (inclusive dates) each season, and each count is conducted in one calendar day. CBC results
can be found at the links below.
2014 Tejon Ranch CBC results
2013 Tejon Ranch CBC results
2012 Tejon Ranch CBC results
2011 Tejon Ranch CBC results
2010 Tejon Ranch CBC results
2009 Tejon Ranch CBC results
2008 Tejon Ranch CBC results
Breeding Bird Blitz
The Conservancy’s Breeding Bird Blitz (BBB) is a bird count conducted on Tejon Ranch annually in late spring. Whereas
the CBC provides information on bird species wintering on Tejon Ranch, the BBB is intended to provide information on
breeding species, although we often see many migrants as well. We use the same 15-mile diameter count circle
established for the Tejon Ranch CBC. BBB results can be found at the links below.
2015 Tejon Ranch BBB results by year
2015 Tejon Ranch BBB results by team
2014 Tejon Ranch BBB results by year
2014 Tejon Ranch BBB results by team
2013 Tejon Ranch BBB results
2012 Tejon Ranch BBB results
2011 Tejon Ranch BBB results
2010 Tejon Ranch BBB results
2009 Tejon Ranch BBB results
Purple Martin Surveys
Purple martins (Progne subis), while relatively common and widespread in the East, are sparsely distributed in California.
A combination of historical declines and the small population size led the California Department of Fish and Wildlife to
designate the purple martin a Species of Special Concern. In contrast to eastern birds, which nest almost exclusively in
man-made boxes, California purple martins nest mainly in natural cavities in trees (with the population in the Sacramento
area using weep holes in highway overpasses a notable exception). Surveys in 2000 in the Tehachapi Mountains near
Tejon Ranch by Brian Williams found over 50 pairs nesting in large Valley oaks. The high abundance of naturally nesting
purple martins in this region led Audubon California to designate an important bird area in the oak woodlands in the
Tehachapi Mountains (Tehachapi Mountains IBA).
To develop a better understanding of the distribution, abundance, and habitat use of purple martins on Tejon Ranch, the
Conservancy is sponsoring nest surveys in the conserved lands on the Ranch. These surveys rely on the contributions of
numerous volunteer citizen scientists, whose efforts have been essential to their success.
2010 Purple Martin surveys
To assess the numbers of purple martins nesting at Tejon Ranch and the types of habitats that they are using, an
expedition was organized by the Tejon Ranch Conservancy, Audubon California, and Western Field Ornithologists. An
enthusiastic crew of 18 birders with many decades of field experience spent the week of June 28-July 2, 2010 searching
much of the likely habitat within portions of the conserved lands on Tejon Ranch, primarily on Tunis, Winters, Middle, and
Cordon ridges. We found at least 23 nesting pairs of purple martins, all using cavities in large valley oaks. Birds usually
chose to nest in larger trees, generally located at or near the tops of ridges in fairly open settings. A paper on the results
of our surveys published in Western Birds is available here. Audubon California also produced a short video of the
expedition that can be viewed here.
Of course, you can't keep a bunch of birders focused on just one species and we compiled an impressive list of 77 bird
species. Cavity-nesters were particularly abundant with 21 different species found. Most of us were stunned by the large
numbers of Lawrence's goldfinches, with this species outnumbering lesser goldfinches almost everywhere we looked.
Totally unexpected was a wood thrush (only the 26th California record!) that serenaded us at our campsite nearly every
morning and evening (video at: http://www.youtube.com/watch?v=RdIzJU028_w ). We would like to thank everyone who
participated in the expedition – the Conservancy learned a lot from your hard work. We would also like to thank Greg
McMillan for putting on a series of great meals for the crew.
2010 Total Species List
2011 Purple Martin surveys
With the help of Tejon Ranch Conservancy, Audubon California, and Western Field Ornithologist a second Tejon Ranch
purple martin survey was conducted the week of June 27-30, 2011. An enthusiastic group of 12 birders spent two days
surveying Tunis, Winters, Middle, and Cordon ridges. We found 21 nests and observed 81 purple martins. The
characteristics of nest trees were consistent with those of the 2010 surveys. All nests were in large valley oaks at or near
the tops of the ridges in fairly open settings. This year, however, the martins were in varying stages of nesting.
Fledglings were observed at some nests, some pairs were feeding nestlings, and others were still incubating. A possible
reason for this is that the prolonged unstable cold weather conditions that occurred throughout the spring delayed the
arrival and nest initiation of part of the population.
Groups also tallied birds seen throughout the day. The group recorded a total of 57 species, with 16 different species of
cavity nesters. Similar to 2010, we were stunned by the huge flocks (one numbering 100) of Lawrence’s Goldfinches.
We would like to thank all of our volunteers. Your help in collecting this data was invaluable. We would thank Greg
McMillan for once again providing us with amazing dinners and a warm fire in the morning and at night.
2011 Total Species List Download
Hunting for Vasek’s clarkia with Kern CNPS (May, 2010)
Vasek’s clarkia (Clarkia tembloriensis ssp. calientensis) is a rare plant on the California Native Plant Society (CNPS) List
1B.1 – considered seriously endangered in California. It is known from only three locations, all on the White Wolf area of
Tejon Ranch near Caliente Creek. The status of Vasek’s clarkia in these locations has only been periodically
documented over the last 25 years, and the population size has fluctuated significantly from survey to survey. In 2010 the
Conservancy hosted the Kern County CNPS to look for Vasek’s clarkia at these known locations and to document its
current status. Read More.