Expert: Roger Lederer - 6/29/2011

Question
Hi Roger,

I live in Plainwell, Michigan (just north of Kalamazoo) and we've seen a few basic Baltimore Orioles here in town. However, one oriole that has visited our yard a couple of times has struck us as odd. It is a bright yellow more so than an orange, and it's patterned more like a male than a female. In other words, at least superficially, it seems to resemble the more southern/western orioles such as Audubon's or Scott's orioles. Unfortunately we haven't had a chance to get better field marks (yet#. The pattern appears bold rather than wishy-washy or mottled, such that it seems to be an adult male.
Could it be a particularly yellow variation of a Baltimore Oriole #I don't know how much they can vary) or should I strongly consider the possibility of its being an accidental Scott's or even an Audubon's?

Answer
It is highly unlikely to be a Scott's or Audubon's. Yellow and Red (and thus orange) coloration in birds is variable and depends partly on the food they eat - red berries, for example. So a lack of red berries in the bird's diet may be the factor responsible for the color. Less common is in complete albinism where the color is diluted, but then the whole bird would be lighter.