I concur with Tina Mitchell: Young black-headed grosbeaks in my neck of the woods make the same calls when begging to be fed. It's a plaintive, descending sound, often as a single note but usually followed by one or two quicker ascending calls and resolving on that descending note. It's like a wolf whistle, but sung sad with a one-note intro. Listen a few minutes, and the telltale squeaky "chip" of an adult arriving usually follows.
I have been watching five or six juveniles in my backyard do this over the past few weeks. Until Mike's recording, I hadn't heard this call for the species on various online guides. John Ealy Roxborough Park, Douglas County CO -- You received this message because you are subscribed to the Google Groups "Colorado Birds" group. To unsubscribe from this group and stop receiving emails from it, send an email to cobirds+unsubscr...@googlegroups.com. To view this discussion on the web visit https://groups.google.com/d/msgid/cobirds/23d8d089-81fd-4fb6-a148-9e09f322e90fo%40googlegroups.com.