I've been looking for other instances of calls that sound similar to those very human-sounding AAAAHHHH vocalizations in the MRP recordings. Anecdotal sources are a good start, with due consideration of the source, but recordings are always better. From that perspective I've come across the following things that help move those suspect calls toward the realm of possible squatch calls...
First, there's the report from an MRP member of similar recordings made in southern Ohio some years ago, and subsequently reported in local news papers. I don't have those recordings but I'll take the guy at his word.
Second, there's the comment from one of the more experienced members of the BFRO board who reports hearing an identical call in the past. I subsequently contacted that person and was directed to the specific call in the recording. Interestingly, it was probably the 'most" human sounding of all the AAAAHHHH calls that this person had experienced.
Third, there are the guest recordings on Stan Courtney's website which include cries that, while not identical, are somewhat in the ball park of these higher pitched, possibly juvenile, vocalizations.
Fourth, through my growing contacts within the BF research community, I've been privileged to receive access to unpublished recordings for the purpose of examining the audio contained therein. The credibility of these recordings are underwritten by the character of the researchers who generously provide them. And in at least one instance I've heard repeated calls that are similar in nature to the MRP AAAAHHHH vocal.
And finally, I have come across a credible recording of some calls that sound rather similar to the MRP AAAAHHHH vocals, although far more energetic. These are more of a rapid escalating scream with a rapid drop off than the extended calls in the MRP recording. But they possess a very human characteristic to them which further opens the door to some sasquatch sounds being easily mistaken for human vocalizations.
These vocalizations were recorded by John Andrews and Darrold Smith in Washington State. The spectrogram of the calls can be seen here:
and the recording can be heard at the 1:51 point in the 6th recording on this website: