Friday, October 9, 2009

Name that Junco

Posted by Kirk
An interesting bird showed up at the Lee & Rose Warner Nature Center today during banding. There were three juncos in a net. One was male, one a female and one didn't seem quite right. There are a number of different types of Dark-eyed Juncos in North America. The ones we commonly see in Minnesota are the Slate-colored variety. They are essentially all gray on top and white on the bottom. If you look carefully though you can distinguish males and females as the females are slightly brownish gray on the back while the males are more pure gray.

What caught everyone's eye about the third Dark-eyed Junco, the one in all the photos here, was that the back of the bird seemed very brown but the head did not. In fact, there is no brown on the head whatsoever. The head also seemed to be darker than the rest of the bird but not extremely so.

Our first reaction was to consider calling this an Oregon Junco. The complete lack of brown on the head makes us think male but then again it isn't as dark a black as one would expect. What this comes down to is that there are a lot of intergrades when it comes to Juncos and it can be hard to draw a clear line between different sub-species.

Here's more photos. What do you think? Things to note:

1) No brown on head but clearly brown across back, brown extends slightly onto wing.
2) Bib is convex (like an Oregon Junco), not concave like a Slate-colored
3) Only very limited brown on the flanks

I welcome your thoughts and comments.



Betsy said...

Possibly an intergrade with a Cassiar form? Or possibly within the range of Slate-colored variation for this pesky species? Way beyond my expertise at any rate.

Have you seen the interesting and extensive discussion by various experts of the ID problems presented by such birds on the Ocean Wanderers website (which I think I once found linked in a post on the Frontiers of Field Identification forum)? Here it is:

The associated photos posted on Surfbirds can be found by entering Juncos and Connecticut in the Species and Location boxes of the search tool on the left side of this page:

I note that there's a drawing of a bird with a convex bib in the set of drawings of Slate-colored variations on the second Ocean Wanderers page, just to confuse the issue even more.

Unknown said...

It looks like a late summer (worn) version of the Oegon (thurberi) in my Nat Geo Complete, or it could be a hibred between a Slate Colored and an Oregon.

T.R. Michels

Dani said...

Very interesting! I'm from Victoria, BC (but originally from Ontario where we saw the slate-coloured) YOur bird dos indeed look liek the Oregon, however with a bib that large I would expect it to be black, and be a male! there are so many variations in the grey hood out here-but I dont' believ I've seen one quite like yours! Danielle M.