I have not heard that many recordings of begging Great Grey Owl chicks. This recording is from 1.54 AM when the male comes with a rodent to the two (at least) young roughly 2 weeks old. You can also hear the lower frequency begging call of the female. The young beg with "calls without vowels".

Uppland. June 8, 2025.
Mixpre 3ii + Wildtronics Stereo Parabole

Great Grey Owl begging calls from young

Field sound recordist and archivist of vanishing sounds in natural Iandscapes. Highly commended in the Sound of the Year Awards 2024 - Best Natural Sound.

Great Grey Owl begging calls from young

Bo Söderström