Date: 1/16/25 6:23 am From: Jim Felley <jdfelley...> Subject: [MDBirding] DC under the Polar Vortex: Grebes and gulls
You may have seen on the news that the Great Lakes are freezing over earlier than usual, due to the succession of polar vortices we have been experiencing.
Especially when Lake Erie becomes ice-bound, wintering grebes are displaced and head south, looking for open water. Often the first they find is the Chesapeake Bay or the Potomac, and we can see an influx of grebes, in particular Red-necked grebes. Keep an eye out! Under such conditions, Riley's Lock has been a good place for these guys. Also, a commonplace observation is that you rarely see grebes flying. At Riley's Lock you will often see them in flight,. The current drifts them down to the rocks at Violett's Lock and they have to fly back upstream.
The Tidal Basin may freeze over as subfreezing conditions continue. When this happens, there may occur a event called 'winter-kill', where the ice blocks oxygen exchange with the air, and fish die from hypoxia (especially shad and river herring). Their dead bodies float up and accumulate under the ice and this attracts hordes of gulls. A frozen Tidal Basin with winter-kill happened in 1994 and 1997. To my knowledge the Tidal Basin has frozen over once since 2000, and then only briefly. Climate change!
Good birding to all
Jim Jim Felley Clarksburg MD
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