[EBB Sightings] Pac Slope Flycatcher vocalization

Just before noon at William Cann Memorial Park on Marsh Hawk Rd. in Union City I heard a LOUD sustained, burry/raspy "weeee" (I couldn't discern any initial strike that would be denoted by a consonant like "teeee") being given repeatedly in the oaks near me. I located 2 adult Pac-slope Flycatchers (2 very whitish wing bars each), one of which was leaning forward almost parallel to the branches it was on loudly giving this call as the 2 worked their way thru the tree. The call was a loud, single pitched (I didn't note any rise or fall in pitch), very raspy "weeee" with a duration of about 3/4 second every time. I couldn't quite locate any reference to this call on BNA Online unless it is similar to the call described of chicks -
"Chicks give sip similar to adult tsip or song?s seet ! (but of less amplitude) and very soft rasp similar to ti-ti-ti vocalizations (Ainsley 1992)."
However, this long, raspy call was anything but soft! The bird's posture did remind me of a begging fledling, the bird was definitely an adult, very often giving the call w/ the other bird well behind it & was foraging on its own. Can anyone help w/ info on this call/behavior? Thanks.

Joe Devine
Modesto, Ca