Subject: [Tweeters] sno-falls peregrines
Date: Mar 29 10:06:07 2008
From: Martin Muller - martinmuller at msn.com


Dave, Tweets

Martin Muller here. A member of the Falcon Research Group. Giving you a heads-up that Bud Anderson, director of the FRG, is out of town during Spring Break.

Thanks for keeping us abreast of the Snoqualmie peregrines. I always appreciate the updates on tweeters.

I've been on the FRG team of peregrine banders for a number of years and my answer to your observation that laying dates have more to do with day length than weather is correct, although this is influenced by individual females and their age. Some females are consistently early or late, and then young birds tend to be (up to a couple of weeks) later than older birds. As they get older the laying dates may move back.

In general we expect peregrines in this area to lay their first egg sometime around the last few days of March. Give or take a few days (or sometimes weeks).

Weather, especially heavy rain, will have a major influence on hatching success. Especially natural ledges with poor drainage often will fail due to heavy spring rain. If the ledge is inundated, the eggs will sometimes literally be cemented onto the ledge, and fail. If this happens early enough in the season the birds may try again that season, but I'd say if it happens past mid-incubation they will likely be unsuccessful that year.

Hope this is of help.

Martin Muller, Seattle
martinmuller at msn.com<mailto:martinmuller at msn.com>