In the same area that my wife and I saw an adult male rose-breasted grosbeak last weekend, today, several folks witnessed a possible rose-breasted X black-headed grosbeak. I did find this bird last week but failed to recognize its importance.
Reasons for thinking this is a hybrid: 1. Looks like an adult male black-headed grosbeak; with exception that from the upper breast down - including flanks, it is off-white; and it's upper rump had some white blotching on it. 2. It's non-stop song is distinctly rose-breasted. I would play a rose-breasted song and it always repeated it; an exact copy. If I played a black-headed grosbeak song; it ignored it. Both songs were from Thayer's Guide to Birds of North America, the source of which are all Cornell recordings. This bird has been found in the same location now 3 times over a week. Always quite vocal. Easily called in using a rose-breasted song; while it completely ignores a black headed song. Google Map <http://maps.google.com/maps/ms?msa=0&msid=200935023114083776748.0004a7ade4a 69007432f4> noting exact location for this bird. You will know you are at the right place for this bird as there is some sort of 3 foot white post on the side of the road away from the willows/alder/narrow-leaf cottonwood. It will sing from the riparian area or fly across the road and from the Ponderosas. Since the adult male rose-breasted grosbeak I saw last weekend is here in breeding season, outside of what I think of as migration for these birds, it seems quite possible that this bird and others may have been breeding here for more than a year and that perhaps at least one may have hybridized with the many black-headed grosbeaks that breed here every year. Sibley's guide to western North America indicates that hybrids are not uncommon along the areas of range overlap. I don't have a lot of experience with hybrids, and there seems to be some possibility that this could simply be a first-summer male rose-breasted. It sure appears to be a black-headed from the breast up however. Jeff J Jones ( <mailto:[email protected]> [email protected]) Teller County - 8500' - Montane Woodlands -- You received this message because you are subscribed to the Google Groups "Colorado Birds" group. To post to this group, send email to [email protected]. To unsubscribe from this group, send email to [email protected]. For more options, visit this group at http://groups.google.com/group/cobirds?hl=en.
