Tilden Nature Area, Contra Costa, California, US
September 2, 2016, 8:30 AM - 11:00 AM
Golden Gate Audubon Society First Friday Bird Walk, September 2, 2016, at Tilden Nature Area (to Jewel Lake and back again).
Our theme today was Breeding Bird Atlases, with an emphasis on the South Bay Area ones of Monterey and Santa Clara counties, and the East Bay ones of Alameda and Contra Costa counties. A worldwide review of 275 bird atlases (Emu, 108: 42-67, 2008) by Dunn and Weston found them for 50 countries and 6 continents, most (82.4%) for Europe and North America. Most are managed by ornithological societies (the pattern in our area). Nearly 28 million records, with at least 108,000 contributors, covering 31.4% of the Earth's surface. The grid size for our local atlases has been 5km squared; the smallest in the world has been 0.02km squared, and the largest grids were 3092km squared (Australia, which still required about 2500 sectors).
Dunn and Weston found that breeding bird atlases are an underused resource; some publications use them (Monterey's has been cited about 20 times since publication in 1993- a San Jose Master's thesis, a University of Leicester (!) Ph.D., an article by Kimble Garrett on introduced parrots; Santa Clara’s, published in 2007, was cited for an article on mercury and the Common Yellowthroat at New Almaden Mines, and 4 other articles) but mostly natural resources inventories for various environmental assessments use them, and that's it. They suggest that documenting range and population changes, suggestions of what environmental changes might bring, patterns of movement (need to save the non-breeding habitats, too!), conservation planning, documenting arrival and departures of introduced species, even commercial uses (where and when to send tourists to see birds of interest)- all could be the "added value" of breeding bird atlases, beyond the citizen science, education and recreation values we commonly celebrate.
Let me know if you want the summaries and some highlights of the south and east bay atlases.
Here are the 15 species seen by Friday’s 36 observers:
Best of Boids!