Thanks Tim, Alan, Ken, Colleen and Russ!
Colleen - This one really wasn't intended as a prelude for a finished piece, it was just done as a sketch/quick study - and Russ actually hinted at my primary reason for doing it...that being the massive bills on these birds. I have issues with bills anyway - maybe because I know birds well enough that I can instantly tell when things aren't 'right' - but doing the Evening Grosbeak bills in other sketches has been a challenge, particularly straight-on views. So here I tried to get a few different angles on the bills for practice. It's certainly not a conventional composition, and sometimes I think that's a good thing - otherwise compositions can get too formulaic; sometimes different is good. I probably wouldn't consider doing a studio piece with this composition, although I like the unusual arrangement of the three birds, because the two sides are pretty empty of other elements. I might consider cropping it to a slightly vertical, or square, format with the three birds dominating. More likely, I would come up with a completely different composition showing the birds in a bit more expected habitat - here they were chowing down on seed I had spread on our gravel walkway.
And Russ, you are definitely correct - getting those bills correct is a big challenge!