Peregrines are probably the fastest of all animals under their own power and have captured the imagination of people for thousands of years. Adults (on this page) are dark slate-blue above and barred below. Juveniles are brownish above and streaked below; these falcons are all yearlings, molting from juvenile into adult plumage. Peregrines of all ages have a characteristic stiff, powerful flight.
The female eating the mew gull was on Bolsa Chica State Beach in Orange County, California. She was exceptionally tolerant; I was able to approach within 10 meters and photographed her for 40 minutes until she polished off the gull. She then flew a half-mile to some dead trees, where she sat and digested for several hours. Another page shows a second-year female with a white-faced ibis; more photos are here.
Immediately below are images of a partially molted yearling in southern California; other images show her several months later, nearly finished with her molt. The bird sitting on a rusty pipe is a 'tundra' peregrine, of the small, relatively pale Arctic-breeding race, photographed in Barrow, Alaska. Both birds are showing some of their first blue-gray adult feathers on the back but are mostly in worn juvenile plumage.
Confession: all of these (with the exception of the 'portrait') were wild birds but a few were banded, and I digitally removed the bands.