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Summering Red-breasted Merganser continues in Penasquitos Lagoon, Del Mar July 9

This subject bird (I think found originally this season by Steve Perry on June 25) continues its summer vacation, loafing with 5 Double-crested Cormorants today on a muddy sand bar in Los Penasquitos Lagoon, somewhat viewable from Carmel Valley Road, Del Mar.  I wonder if this may be the same bird that summered here  with the Red-necked Grebe as reported by Nancy Christensen in mid June 2016?  It is either a female or basic plumage male, but  could not judge amount of white in forewing, and even if I could, would not be sure!

   Most of these mergansers are gone by May, but  in Unitt (2004)*, I read that  some do occasionally choose not to migrate and then stay the summer here.  From eBird I see that summering Red-breasted Mergansers over the past couple of years have not been all that unusual, with birds spotted also at Oceanside, Lake Hodges, Point La Jolla,  north and south San Diego Bay, and  Tijuana River Slough and Tijuana River mouth areas.  Sometimes more than one individual at a time has been sighted, up to 4 and 5 in one day at the Tijuana NWR area in summer!.  I wonder have these summering birds increased, or are sightings in recent years similar to those in the past?  I read in Birds of North America online " Overall, the Red-breasted Merganser remains one of the least understood species of waterfowl in North America." 
* My Unitt 2004 is falling apart–I need another copy! (I know it's online, but I like to have the hard copy,  too, to thumb through)

Susan Smith

Seiurus Biological  Consulting
Del Mar, CA 



Susan Smith
Seiurus Biological Consulting
Del Mar, CA
Source: SanDiegoRegionBirding Latest Reports