Nest Site Monitoring 03-16-08

I went to the second peregrine nest site this morning with my friend Cheryl. First, we met at 6:30 am on the western edge of Treasure Island, in the middle of San Francisco Bay to see if we could see a nest exchange for the pair of peregrines that will likely be nesting on the W4 tower of the Bay Bridge. We saw both peregrines. One was first spotted flying over W2, headed down the usual route (following the bridge to shore, then turning north and heading past the new Rincon Tower, then continuing north. This one made it as far as the Transamerica Building, where it was joined by a second falcon. From TI, we are about 2 miles away to ID of the birds as individuals is not possible. It was only after watching for awhile that we were comfortable ID’ing them as peregrines. They stayed together for several minutes, a stoop, lost them both as the went behind buildings, found one again. Kanit followed it with her scope as I turned mine back to W4, just in case the other showed up. And it did. I saw it near W4, then a flight behind the tower, reappearance and a disappearance under the bridge deck between W3 and W4. All this time, Kanit was following the other and calling locations as it took the “peregrine highway” back south, then east over the bridge span. The peregrine between W3 and W4 popped down from its location and headed east, disappearing under the area of last year’s nest location (just east of the tower on the north edge of the underdeck). It again popped out and disappeared under the deck slightly east of the previous spot. The other peregrine landed in the meantime on top of W3. By then it was 7:30. We had determined that they are not in hard incubation since both were off the nest for at least 1/2 hour. I guess this means we will have to repeat this again next weekend.

Kanit stopped by to visit Espie at the Siebel building. She saw the FWS band on the left leg and was able to confirm it was Espie. She watched her doing some eating and some flying with gulls.

In the meantime, Cheryl and I headed out to the second (possible) nest location. After a considerable drive and and long walk, we found the area described by the ranger I spoke with. There are many areas of rock outcroppings, with caves with overhangs. We found one area that was marked with ‘whitewash’. It is at the top of an outcropping. On the far side are two large caves, one below the other. The whitewashed area would be a perfect spot for a peregrine to watch over the nest area. We got to the area around 11 am and stayed until 1:45 and did not see any peregrines.

All three of us will be regularly monitoring these two nests sites.


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