I get a kick out of hybrid birds- like Easter Eggs hidden in video games, they offer a treat that may be hiding in plain view but undetected without some scrutiny and/or detective work. I’ve previously posted on a couple of hybrid gulls that were fun to suss out (Herring x Glaucous and Herring x Glaucous-winged) but for this installment I’ll switch to another hybrid-prone avian family, the Anatidae (ducks, geese, & swans.)
I was alerted to an interesting hybrid duck not too far from my home base last weekend via an eBird report of a hybrid Barrow’s x Common Goldeneye (BAGO x COGO). So on Sunday, 4 January I trooped on over to the pond in Broomfield, Colorado to see what I could find. On this day birds were pretty scarce as a recent very cold bout had capped the lake with ice but a bubbler system maintained a patch of open water. Finding the bird was simple as it was the only duck there (with about 18 American Coots who probably wished they were significantly farther south) and I was able to get some digiscoped video to scrutinize. Interestingly, this is the 4th hybrid bird I’ve seen on that pond- the two aforementioned gulls plus a Redhead x Ring-necked Duck. Another nearby pond had a standard Common Goldeneye that I also filmed for comparison.
Anyway, the video will mostly speak for itself, but I think you’ll see that the hybrid is pretty intermediate between both parent species in most regards. In particular, the facial spot is more elongated than would be expected in COGO but not as fully crescent-shaped or as far above eye level as expected in BAGO. The spot also has a bit of an indentation near the top that neither parent would normally show. The scapulars have less white and more definition between the vertical bars than COGOs show but have more white and less defined “piano keys” than expected in BAGO. It is interesting to see how much the head shape changes depending on the bird’s activity but at least in the first clip the bird appears to have a steeper forehead than usually seen in COGO. Overall, though, the head doesn’t appear to have the exceedingly steep forehead of a BAGO. Finally, a hint of a black spur intruding down into the white upper flank is visible in this bird, a feature much more prominent in BAGO but absent in COGO adult males.