This type of call is attributed to immature Rose-breasted Grosbeak on the Evans/O'Brien Flight Call CD. Below is a comparison between this presumed immature RBGR call and a Wood Thrush.
Wood Thrush, 9-21-06,11:23 PM
Rose-breasted Grosbeak,9-30-06,11:11 PM
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Rose-breasted Grosbeak recorded on 9-30-06 at 11:11 PM