I spent Sunday morning birding the Mt. Diablo Summit area. Temperatures were in the mid 90's but with the occasional breeze and active birds, the weather was tolerable and the birds quite interesting. The goal was to find a Black-chinned Sparrow in the burn areas, but I was not successful. My route was parking by Muir picnic area, walking to the Devils Elbow, then to Prospectors Pap and about 1 mile down the road in the burn area that is recovering nicely (maybe 6 or 7 miles round trip).
- A California Thrasher that appeared to be hawking for insects!! I watched the Thrasher fly twice on sallies about 70 feet away where it changed directions and appeared to be chasing bugs in air! There were about 6 Scrub Jays also hawking for insects in this area - could the Thrasher have picked this habit by watching the Scrub Jays? I have seen Scrub Jays hawk and sally for insects several times before in Mitchell Canyon but never imagined a Thrasher would do try to feed like that.....
- A decent late migrant movement with multiple Pewees, Olive-sided Flycatchers and Pacific-slope Flycatchers and a Western Tanager seen before 10 am. (Migrant activity ended at around 10 am).
- A singing Bells Sparrow above the Road.
- Rock Wren, Rufous-Crowned Sparrows, plus Lazuli Buntings.
- Maybe 8 or more species of butterflies.
- Late wildflowers with many Mariposa Lilly's, Globe Lilly and Mt. Diablo Penstemons blooming.
I think in May and early June the Diablo Summit area is the most under-birded, highest potential birding reward location in Contra Costa county with passerine migrants dropping in at the Summit - which is also the highlight time to see wildflowers. I think the Diablo summit area should be birded more. A previous trip to the Diablo Summit in early May this year reinforced my thoughts that this is a good area for migrants when I saw 4 or more Cassin's Vireos within 150 yards of the summit building when the rest of the mountain below was quiet as I had biked up the mountain.
The trails in the summit area are often steep and rocky so be prepared, but the views are worth it even if the birding is slow.