![[San Diego County Bird Atlas Project]](../birds/images/bnr_birds.jpg)
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| Birds & Mammals BRCC
CONTACT: |
Birds Birds will be sampled by three methods. Around each of the 20 camp sites, we will establish 10 points along a path corresponding as closely as possible to the area covered in 1908 while encompassing the maximum habitat diversity possible along a route that can be covered in one morning on foot. The route will be walked in the same way on each of four visits to the site. All birds along the route will be counted, with each of the 10 points being the center of a variable-distance count for 7 minutes, according to the Museum of Vertebrate Zoology’s protocol. The route will be covered between dawn and 10:00 AM. A subset that can be covered in one hour beginning at dusk will be selected for surveys of nocturnal birds. No recordings will be used on the walk out, but recordings of the relevant species may be played to elicit responses on the walk back. The routes and points will be documented by photographs and coordinates recorded by means of the global positioning system (GPS).Second, birds will be trapped by mist net, with five nets deployed around the camp sites in locations where the trapping is likely to be successful (location amid vegetation, shaded through the morning, sheltered from wind). The nets will be set up and closed in the evening, then opened before dawn the next morning. We will record the time each net is opened and closed as well as the number and identity of birds caught. The time of closure will have to be determined in the field by sun and wind conditions, but the recording of the time they are left open allows a calculation of capture rate. The nets’ situation and location will be recorded by photography and GPS as for the count points. Because some camp sites are in the famously windy San Gorgonio Pass, and because mist-netting is ineffective in even light wind, we must anticipate that this technique may not always be practical at every site.
Third, all birds observed incidental to other activities will be noted. Time not devoted to more structured sampling will be used to search areas visited by Grinnell and Swarth’s team on a more informal basis. For a few species with very localized distributions, such as the Black Swift (Cypseloides niger) and Whip-poor-will (Caprimulgus vociferus), we will make trips to previously reported sites to assess the species’ current status even if they are not in areas surveyed by Grinnell and Swarth. |
