Wednesday, May 13, 2009

Update: Migration May 13-16

Last night there were strong winds out of the south, and a look at the radar picture late at night showed what appeared to be very large numbers of birds crossing Lake Erie. Today (Wednesday May 13) there was obvious turnover in the migrant traps along the lake shore. At the Magee Marsh boardwalk, there were many more Swainson’s Thrushes and Cedar Waxwings than the day before, a modest influx of Scarlet Tanagers and Baltimore Orioles, and seemingly fewer Yellow-rumped Warblers and Ruby-crowned Kinglets. Warblers were present again in excellent variety. I was only there for a short time this morning so I don’t know the total number of warbler species present (I only saw / heard 20 species), but what I saw included two male Mourning Warblers in separate areas near the west end of the parking lot. Mourning is a classic late-May migrant and I had heard of only one individual at the boardwalk before today.

Tonight (Wednesday night), between the high pressure center that’s moved off to the east and a low-pressure center sitting to our northwest, we’ll have a strong flow of warm air coming up all the way from the western Gulf Coast, and a huge number of migrants should be riding that train northward. It’s not a sure thing that they’ll actually reach us, because there will be a lot of rain in the area locally, and the migrants may be put down before they get anywhere near the lake shore. But if they do happen to get through, Thursday could be a very good day all along the south and north shores of Lake Erie -- that is, Magee and Point Pelee could get equal shares of the wealth.

Following tonight’s and tomorrow morning’s weather, a low pressure area will move past us to the north and winds will probably shift to the north Thursday night, shutting down migration, so Friday probably won’t see any influx of new migrants. But with the rapidly changing weather of this season, the wind is supposed to shift around to the south again Friday night, probably bringing, again, another wave of migrants on Saturday. At this point it’s hard to say whether Thursday or Saturday will be the bigger day -- Thursday has greater potential, but it could be partly shut down by overnight rain. One way or another, there should be a lot of migrants around for birders who visit this coming weekend.

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