Thursday, May 21, 2009

Weekend Migration Forecast: May 22-24

The last few days (Tuesday - Thursday, May 19 - 21) have been hard to interpret in terms of the migrants that we’re seeing on the ground. Bird numbers seemed lower than I had expected on Wednesday and Thursday. During the preceding two nights there had been favorable winds from the south, and the radar picture late at night had shown large numbers of birds on the move from well to the south of us, but the numbers of migrants along the Lake Erie shoreline -- particularly in the woods at the Magee boardwalk -- have seemed low.

I talked to Mark Shieldcastle (Research Director for BSBO), who has been looking at weather and migration in this area essentially every day in spring for the last 30 years, and asked for his perspective. Mark felt that we were seeing a migration on a very broad front, the birds filtering north, not forming large concentrations anywhere. He also pointed out that there have been large hatches of midges recently in the marsh region, so the birds can feed heavily without having to move very far, and since the woods and thickets are now fully leafed out, the birds are less conspicuous. The diversity in the area is still excellent -- the BSBO banding operation has had more than 20 species of warblers every day this week, with goodies like Connecticut, Mourning, Orange-crowned, and Hooded -- but birders are having to work a little harder now to find these birds.

(Incidentally, as I’ve mentioned before, you can find fascinating info by checking the BSBO website for the latest data from the banding station, and for Julie Shieldcastle’s “Bander’s Blog.”)

I was out checking various spots today (Thursday May 21) and found relatively few birds near the west end of the Magee boardwalk, probably at least partly because of strong winds from the west-southwest. On the Wildlife Beach I found a lot of warblers (mostly Am Redstarts, Wilson’s, and Blackpolls), but mostly just east of the dike at the west end, where the thickets are more protected from the wind. I had a much higher density of migrants in the woods at Ottawa NWR in a brief check there. Again I was concentrating on areas sheltered from the wind, on the north and east sides of the wooded areas (see our map of the walking trails at Ottawa for a better idea of how the woodlots are arranged).

Tonight (Thursday night) the winds are supposed to continue more or less from the southwest all night, but right around dawn, a cool front is supposed to pass through and shift the winds abruptly so they’ll be coming from the northwest. If the timing of this is just right, it could make for a better concentration of birds in the migrant traps along the lakeshore. I think the best bet on Friday morning will be to check the standard lakeshore areas (like the Magee boardwalk area, Metzger, etc.), and then if there aren’t a great number of birds there, go to check areas of woods just to the south. The wooded areas at Ottawa NWR are excellent on some “off” days for the boardwalk. Along the Ottawa trails there are a lot of areas that look perfect for Connecticut Warbler. I’m sure there have been a few in there this week; it’s just a matter of finding them.

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