I recently spent a day between two of the more well-known sites for this species: Peace Valley Park (86 individuals) and Lake Nockamixon (107 individuals).
Roughly 70% of the birds that I observed were adult types. Further, I was surprised by the number of 2nd cycles present (far more than 1st cycles, which were notably scarce).
|2nd cycle LBBG. Bucks County, PA. 28 March 2014.|
|Adult-type LBBG. Bucks County, PA. 28 March 2014.|
As I wrote in Birding magazine last winter (2013), the presence of this species in North America remains an enigma. Where are they breeding? What subspecies is found on the west coast? And to what extent are they hybridizing with American Herrings?