Photo 1. Adult male purple martin in flight on Tejon Ranch. Photo by Bob Steele.
Figure 1. Range map of the purple martin (Tarof and Brown 2013).
Photo 2. Adult male on nesting cavity, Tejon Ranch. Photo by Bob Steele.
Photo 3. Example of adult female and second year purple martin plumage on Tejon Ranch. Photo by Bob Steele.
Figure 3. Range of purple martin in California (CABSSC).
Photo 4. Valley oak nesting cavity on Tejon Ranch. Photo by Robin Prather.
|Photo 5. Ridge on Tejon Ranch supporting purple martin nesting trees. Photo by Nicole Stephens.|
|Photo 6. Typical upper 1/3 of the slope nest tree position on a ridge on Tejon Ranch. Photo by Nicole Stephens.|
The first purple martin survey was conducted on Tejon Ranch by the Tejon Ranch Conservancy in June, 2010. The survey was then conducted again in June of 2011 and June of 2014. Conservancy staff and volunteers survey the ridges of the Ranch for a week during the month of June. Each year previously known nesting trees are visited and new nesting trees are often found as well. So far the Ranch has a total of 40 nesting trees. We found 23 nests in 2010 and 21 nests in 2011. The 2014 survey found a total of 12 nesting trees, with 8 of those being new trees .
The major ridges on the Ranch include Cordon Ridge, Middle Ridge, Winter’s Ridge, and Tunis Ridge. Cordon Ridge has a total of eighteen known nesting trees. This year we found four active nesting trees, one previously known and three new nesting trees. There appeared to be only one active cavity in each tree. Middle Ridge has seven known nesting trees, two of those are new nesting trees found this year. One of the new nesting trees appeared to have two active cavities. Winter’s Ridge has six known nesting trees, three of those being new trees discovered during this year’s survey. One of the trees had 2-3 active cavities, which might have just been different entrances to the same nest, illustrating another challenge with accurately surveying purple martins. The three previously known nesting trees were not active this year. Tunis Ridge has a total of nine known nesting trees. This year only two nesting trees were found and they were both previously known.
|Figure 4. Location of purple martin nesting trees on Tejon Ranch.|
Figure 5. Location of purple martin nesting trees and ridges on Tejon Ranch.
Airola, D. A., 2009. Status of the purple martin in Northern California: Results of a pilot study to develop and apply a survey method. US Fish and Wildlife Service. Sacramento, California.
Airola, D. A., and Grantham, J. 2003. Purple martin population status, nesting habitat characteristics, and management in Sacramento, California. Western Birds 34: 235-251.
Airola, D. A., and Kopp, D. 2009. Recent purple martin declines in the Sacramento Region of California: recovery implications. Western Birds 40: 254-259.
Airola, D. A., and Williams, B. D. C. 2008. Purple Martin (Progne subis), in California Bird Species of Special Concern: A ranked assessment of species, subspecies, and distinct populations of birds of immediate conservation concern in California (W. D. Shuford and T. Gardali, eds.), pp. 293-299. Studies of Western Birds 1. W. Field Ornithol., Camarillo, CA, and Calif. Dept. Fish and Game, Sacramento.
Grinnell, J., and Miller, A. H. 1944. The distribution of the birds of California. Pac. Coast Avifauna 27.
Shuford, W. D., and Gardali, T., editors. 2008. California Bird Species of Special Concern: A ranked assessment of species, subspecies, and distinct populations of birds of immediate conservation concern in California. Studies of Western Birds 1. Western Field Ornithologists, Camarillo, California, and California Department of Fish and Game, Sacramento.