On August 2, 2009 I recorded juvenile Yellow-headed Blackbird (Xanthocephalus xanthocephalus) begging calls at Vernon Marsh, Waukesha County, WI..Yellow-headed Blackbird juvenile begging calls
One juvenile is in the foreground in a small bush. Behind it is another bush with a least one more juvenile. At 21s. an adult female lands with food in front of the first juvenile. You can hear an intensification in the begging calls at that point, with an increase in the frequency of calling and also an increase in the length of the calls.
I found another recording of juvenile Yellow-headed blackbirds at the Borror Laboratory site, recorded on July 3, 1970 in North Dakota. The begging call in this recording is very similar to the one in my recording, as can be seen from a comparison of the spectrograms.
My recording is on the top and the Borror recording on the bottom.
I’m not sure what to attribute the differences in the wave form to. Could be they are from different periods in the development of the juveniles. It would be great to obtain a series of recordings of one individual over the course of its first summer.