This morning the Peregrines started the day under overcast skies, little wind, and temp at 49F. The day ahead looks to be cloudy, with a high near 69. Calm wind becoming south around 6 mph in the afternoon. Tonight, rain likely, mainly before 3am. Patchy fog between 11pm and 3am. Otherwise, cloudy, with a low around 57. South wind around 6 mph. 

In their fourth week of life, the chicks undergo significant changes almost daily.  Around day 25-26, the brown tips to the secondaries become clearly visible, and the number of colored feathers visible on the breast increases noticeably.  Behaviorally, they are rarely resting on their tarsi anymore at this age. In the cover image, the chicks are loafing in the nest box, and the female is perched looking around…..notice the changes in feather coloration.  Here they are upright and more on the lookout at passing action!

In terms of feeding times, the pattern is irregular overall.  The young are twice as likely to be fed during the early morning and evening periods than middle of the day.  There tends to be a higher frequency of feeding visits during morning or late afternoon/early evening.  Interval times between feeding visits usually averages about 2 hours, and average duration of a meal runs about 8-11 minutes, with duration of meal time increasing a bit as the chicks get older.

Literature cited:

Ratcliffe, D. 1993. The Peregrine Falcon. 2nd ed. Carlton, England: T. and A. D. Poyser.

The Canadian Peregrine Foundation, Peregrine Falcon Development – Age Guide; http://www.peregrine-foundation.ca/info/ageguide.html