Wednesday, September 8, 2010

Birdcast Update

The National Weather Service now confidently predicts a cold front's passage during the day today (Wednesday). The first night after a frontal passage often features heavy migration - it certainly did last Friday night/Saturday morning - so Thursday should be a fine day of birding. Winds are supposed to stay NW through Saturday morning, so Friday and Saturday should be pretty good for songbirds, too. In theory, each succeeding day after a front there are fewer birds "left in the well" to come south, so by that theory Saturday will have less birds than Friday, which will have less birds than Thursday. The caveat is wind speed - very strong winds at night can suppress migration, even if they are out of the NW.

On the hawk front, NW winds are what we want, and NW winds are forecast for Thursday and Friday, all day both days, before finally turning around to SW late morning Saturday. It looks like the wind will be strong enough to keep the flight fairly low altitude, at least for Thursday. We're still early in the raptor migration season, but it was only a few days later last year, September 14 to be exact, that the single-day Bald Eagle record was broken, a day when kestrels were flying in off the water in the pre-dawn.

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