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2011 Banding and Nest Monitoring Report

BandingVolunteer and student observers reported on twenty-two Greater Bay Area peregrine falcon nest sites in 2011. While many locations are now known and have been discovered by volunteer observers, our permit conditions prohibit the public disclosure of specific peregrine falcon nest locations to protect nesting birds from disturbance. Here is our status report for the twenty-two sites we observed this year:

One site was occupied by prairie falcons and observations at two other occupied sites were incomplete.

No eggs were laid at three sites where pairs of peregrines were present. We do not always know why this happens but can report that at one site where no eggs were laid, the female was in immature plumage. Four of the remaining sixteen sites failed after incubation commenced but before the eggs hatched. (One nest was on a building, one nest was on a bridge, and two nests were located on natural rock structures).

At least thirty young were produced and survived to thirty-four days of age at sixteen eyries where incubation commenced, for an average of 1.875 young per territory. Eighteen young were banded at seven of the successful peregrine falcon nest sites.

We are extremely grateful to the nest site observers who dedicated their time to visit nest sites in all kinds of weather last spring so that banding was possible. They provided reliable information on the location and status of the nesting attempt so that we could arrive to safely band nestlings at exactly the right time.