"Silent" squirrels...?
Very clear recording quality.
I add to it: if a European red squirrel looks relaxed like a cat that has rolled up comfortably, maybe the squirrel even raises one or both front paws to the chest as if resting and being at ease (and looking especially cute that way) ,
it means exactly the opposite. This is the "scanning" posture, all senses, ears and eyes, are at their maximum performance, and the animal frooze, not to be seen easily by possible predators and to alloow its eyes maximum perfokmance (they see sharp on all their retina, not just in one focus point like humans do). It means that something has alarmed it and that it now carefully scans the environment for threats and dangers. So, what in a cat expresses relaxation and comfort, in a European red squirrel means that it is on its guard and is alarmed.
The lamenting sound you hear in the video, the sad howling low whistle, also expresses alarm, reaction to something bad that happened, and warning others, expressing stress, being on guard.
Some of these sounds are created deep in the belly, and not in the jaw, throat and lungs. Squirrels can at the same time eat and produce these sounds. If you listen close enough you can hear that even small squirrels, even babies already make sounds when eating.
Male animals sometimes make sounds that mimic sounds of young animals, thjis is mostly in mating season, they do so in the presence of females to calm them down and relax them by pretending to be "harmless"
kid animals.