I thought I would forward this short note from my friend Steve Feldstein who
works on climate theory, when he isn't birding.


>Also, I occasionally glance through Tweeters, and noted your discussion about
>the weather and migration along the west coast. Blocks were brought up in
>this discussion. Based on a previous message, you commented that blocks
>were probably rare and probably didn't influence migration. Although there
>are typically maybe two blocks per season, they do persist for two weeks and
>sometimes longer. So when blocks are indeed set up, I'd expect that they
>could have an important influence on migration. However, blocks are most
>prominent during the colder months, so should be more relevant for ducks etc.
>
>Steven
>
>
>
Alvaro Jaramillo
Half Moon Bay, CA

alvaro at quake.net