Blue-winged Warbler x Golden-winged Warbler

Blue-winged Warbler x Golden-winged Warbler hybrid, Peveto Woods, Cameron Parish (Louisiana, USA), 15th April 2014 - copyright Matt Brady

(photo ID: 2115)

Two different forms of hybrid between Blue-winged and Golden-winged Warblers were separately named as distinct species, Brewster's Warbler and Lawrence's Warbler in 1874.  By 1881 Brewster had recognised that they were in fact hybrids, though it was many years before this was to become widely accepted.  A very interesting account by Leo Shapiro of the history - including much more recent studies - of these hybrids was published in Birding magazine (May/June 2005), accessible online here.

Blue-winged Warbler x Golden-winged Warbler hybrid (same bird as in photo ID 2115 above), Peveto Woods, Cameron Parish (Louisiana, USA), 15th April 2014 - copyright Matt Brady

(photo IDs: 2116-2119)

The next one is very similar to pure Blue-winged Warbler so obviously not a first-generation hybrid.  I had to look twice to see why it wasn't a Blue-winged Warbler - I guess it's the extent of white in the wing and the dark at the back of the ear-coverts?

Blue-winged Warbler x Golden-winged Warbler hybrid, San Francisco (California, USA), 17th September 2008 - copyright Matt Brady

(photo ID: 2120)

On this one, superficially closer to Blue-winged Warbler, the yellow wing-bars and the thickness of the dark stripe behind the eye are indicative of a hybrid - the type known as Lawrence's Warbler.

Blue-winged Warbler x Golden-winged Warbler hybrid, Rockfish Valley (Virginia, USA), 13th September 2012 - copyright Marshall Faintich

(photo IDs: 3158-3161)

And in contrast here is one more like a Golden-winged Warbler.

Blue-winged Warbler x Golden-winged Warbler hybrid, Blue Grass Valley (Virginia, USA), 19th May 2012 - copyright Marshall Faintich

(photo IDs: 3162-3167)

Blue-winged Warbler Vermivora cyanoptera
Golden-winged Warbler Vermivora chrysoptera