Monday, August 13, 2012

Bonaparte's and Franklin's Gulls

On Saturday morning, I went birding at Eagle Creek in hopes that a bunch of shorebirds would have arrived with the fronts that had passed through our area. Unfortunately, it appeared that all of the shorebirds left and no new ones came in. Even though there were no shorebirds, finding my first Bonaparte's Gulls of the fall made the day exciting. While I was watching both an alternate plumaged individual and a juvenile, I got to thinking about the questions that we get about how to tell Bonaparte's and Franklin's Gulls apart. Sure in alternate plumage, it is not all that difficult but once they have molted into basic plumage it becomes much more tricky. Here are a few tips that should make identifying these species very easy.

Bonaparte's Gull

  • Thin black bill
  • Pink Legs
  • Distinctive black ear-spot
Bonaparte's Gull (Chroicocephalus philadelphia) Adult non-breeding
Notice all of the features described above, black bill, pink legs, and a black ear-spot. Check out this photographer's photostream on Flickr at

Franklin's Gull

  • Short, thick black bill
  • Black Legs
  • Partial black hood
  • Appears more chunky and less elegant looking than Bonaparte's
Franklin's Gull
This Franklin's Gull shows all of the classic things to look for when identifying this species, short black bill, black legs, and a partial black hood. Also notice the pattern on the tip of the wing. A Bonaparte's Gull will not show this pattern. Check out this photographer's photostream on Flickr at
This should make your process of identifying these birds in basic plumage much simpler but what happens if they are in molt between alternate and basic plumage? Can you identify the bird in this photo?



Unknown said...

Franklin's Gull?

Findlay Wilde said...

I really like these see birds. I was in Cornwall last week watching Gannets diving off Lands End. From Findlay

Dan Huber said...

Great post, very helpful