(Or if you're in the UK, Guillemot or Brunnich's Guillemot). I'm having a bit of an online discussion about the ID of this bird, seen in Cape Breton in June, amongst a large number of Puffins and Razorbills. Thick-billed shouldn't be there in Summer, and Common is an occasional visitor and used to breed there. I can see features consistent with either/ both. This is one of just 2 identical pictures I got. I was on a boat. What do the seabird experts here think?
I agree this is a difficult one Richard. First, it must be said that some Common Murres will show an apparent white stripe on the upper mandible. Sometimes, maybe always, this is caused by reflection of the shiny mandible material in that area. However, this one seems more prominent than I am used to seeing on the 1000s of Common Murres I have looked at and handled over the years. The bird does show the brownish-black feathers characteristic of the Common Murre and the bill looks long enough to be a Common Murre. Murres and Razorbills hybridise and I am sure that Commons and Thick-bills do as well so it's possible that a hybrid is what you are looking at. Their range in Canada overlaps in Labrador and to a less extent even in insular Newfoundland, so the opportunity for hybridisation exists. However, I would not press this one too far. To me the bird looks like a Common Murre with an extra-prominent white stripe on the upper mandible.
Last edited by John Chardine; 08-03-2012 at 07:18 PM.
I looked for an image of a Thick-billed with a Common. Here's one although not the best image, made at Cape St. Mary's in Newfoundland, where they clearly breed cheek by jowl. Note the really thick stripe on the TBMU on the left and and thin line on the COMU to the far right.
This looks like a Common Murre to me. The head looks slim and not blocky, the bill isn't all that thick, and the brownish coloration all look better for Common. If you have any shots of its front, you can ID it from the tip of the white pointing upward on the chest; rounded in Common and pointed in Thick-billed. Below are links to some shots that illustrate this over at BirdFellow.
I thought you 2 might step in! I actually thought it was a Common Murre at the time and from the photos. I posted it on Birds-pix, and Joseph Morlan, who is certainly pretty good, thought it was more likely a Thick-billed. I have sent it to Ian McLaren too, but he hasn't replied yet. Unfortunately there are no other photos of that bird, and I'm unlikely to visit that spot again for at least another year. Thanks for your thoughts.
Common or Thick-billed Murre?
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