The pigeons in Woking are looking nervous. There may be safety in numbers but there's danger in the air.
A pair of peregrine falcons have, for the second year in a row, chosen the top of an office block to nest.
Unlike in the countryside peregrines have no predators in the city and their numbers are on the rise.
Swooping from that height they can reach speeds of 180mph.
The nest box was fitted last year along with a webcam. It became cult viewing with 5,000 people watching as the parents helped their young hatch.
Incubation usually takes 6 weeks so they should hatch at the end of April. To watch a live webcam of the peregrine falcons, click here.