SDFO Meeting Nov 20

SDFO Event _ November 20, 2018 at 6:00 pm is the next meeting of San Diego Field Ornithologists.

Tuesday, November 20, at 6:00 p.m., in the Hoffman Room of the San Diego Foundation Building, 2508 Historic Decatur Rd. Going south on Rosecrans St. in the Midway area of town, turn left on Roosevelt Rd. into Liberty Station and proceed a couple of blocks to Decatur. Parking is available on the street or in the adjacent parking lots. Program: Phil Unitt will discuss “Results of the Resurvey of Joshua Tree National Park and the Mojave National Preserve.” Since 2016 the department of birds and mammals at the San Diego Natural History Museum has extended its resurveys of sites explored by Joseph Grinnell and his colleagues at the Museum of Vertebrate Zoology, University of California, Berkeley, to Joshua Tree National Park and the Mojave National Preserve. The historic studies, which extended primarily from the late 1930s to the early 1950s, serve as a standard for gauging more recent changes. In Joshua Tree, the main theme of change is the decrease of species associated with chaparral and pinyon/juniper woodland, paralleling the decrease in these habitats wrought by drought and fire, plus the drying up of many springs. But the California Towhee has bucked the trend, spreading widely in the park over the past 60 years, a significant range expansion to the east. In and near the Mojave National Preserve, increases and spreading ranges are more prevalent, including an upslope extension of the Black-tailed Gnatcatcher, increases of the Crissal Thrasher and probably Gilded Flicker, further spread of the Rufous-crowned Sparrow, and colonization of the Zone-tailed Hawk. In the eastern Mojave Desert, the cover of Joshua trees has increased, while the cover of pinyon/juniper is changed much less than in Joshua Tree National Park. Possible changes in the status of the stands of white fir on top of the highest mountains still need study.

Click here for Meeting Details and Map.

Final month to renew 2018 memberships! Click the link for SDFO membership instructions. Please make sure to include your current email address.

Nancy Christensen

San Diego Field Ornithologists

President

Nancy Christensen

Ramona