San Francisco Nest Diary 2011:
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May 10, 2011. Three young were banded on April 28. All are doing well, and headed for fledging in about one week. Fledge watch will begin May 13th. Males typically fledge first with females following in one to three days.
April 6, 2011. Three eggs have hatched. Generally three eggs hatch and then the fourth a day or so later. Female peregrines often begin incubation with the arrival of the third egg, causing the fourth to get a late start. At times when food is scarce the late-hatching chick will not survive since it is much smaller than its older siblings at hatching. The young grow to full adult weight in three and one half weeks. Flight feathers grow in during the next three weeks on the nest ledge allowing them to fly for the first time, or fledge, at about six weeks of age.
March 3, 2011: The fourth egg arrived this evening. The clutch should now be complete. Peregrines sometimes lay three eggs and seldom five. Incubation time is about 33 days beginning with the arrival of the third egg. Males share in incubation but females take most of the incubation duty. We will see the female stand up off the eggs and peer at them in a sign that hatching is imminent because she will be able to feel movement and hear the babies cheeping from within the eggs.
February 25, 2011: The first egg of the season was visible this morning at both the San Francisco and San Jose nests. Eggs are laid approximately every 56 hours. Incubation usually commences when the third egg is laid.