Subject: Re: Do Warblers migrate in flocks?
Date: Apr 25 14:42:55 1995
From: Mike Patterson - mpatters at ednet1.osl.or.gov





In the fall one can, if the weather is right (overcast, breeze from the sw)
sit on the South Jetty of the Columbia River and watch the migratints
following the jetty into landfall. I have seen flocks of Blackbirds,
flocks of Robins, flocks of finches.
Warblers usually come in single file. Over the course of a morning
Yellow-rumps especially will come in in ones and twos. They then seem
to congregate in the willows and move south in a herd. Activity peaks
between 7:00 and 8:00 and then all the non-residents seem to disappear.

Here's a hypothesis: The migrants flock. During the day when visual cues
can be used to keep the flock together the flock remains tight. At night
the flock breaks up as birds lose visual track of one another. They regroup
at landfall the next morning.
And suggestions for how we can test this?


--
********************************
* Mike Patterson, Astoria, OR * "Time flies like an arrow;
* mpatters at ednet1.osl.or.gov * fruit flies like a banana."
******************************** - Groucho Marx