Another set of rare birds has been spotted in eastern Iowa — to the delight of environmentalists and to the dismay of some bridge workers. The pair of peregrine falcons built a nest which now contains several fledglings in the middle of the Centennial Bridge between Davenport and Rock Island, Illinois.D-N-R wildlife diversity technician Pat Schlarbaum says the predatory birds were almost wiped out in the 1960s by pesticides.The adult falcons scared off electricians who were trying to replace light bulbs on the bridge. The birds were swooping down on the workers and screeching at them. Also, the nest is right under a tollbooth, but Schlarbaum says the birds aren’t really a threat. There are only three other pairs of the falcons in the state, with nests in Des Moines, Cedar Rapids and Lansing.