You can see her tentatively filling her throat sac with air, but you can tell she doesn't want to be distracted as she prepares to vocalize.
This is where the onboard mics of the GH5 suffer. In situ, you could hear her hoots absolutely filling the forest, but here they sound rather flat. Time to get a good quality shotgun mic or delve into Resolve's sound module.
1:40 first hoot