Flying squirrels are mostly nocturnal and usually avoid flying around during the day, to avoid predators. Not only is this yukkuri exerting a lot of energy climbing that tree, it's also making itself a big target to birds of prey. This behavior goes completely against the basics of survival.
The only explanation for this is that yukkuris are helping the birds of prey to take it easy by flying directly into their mouths.
@Sun: Which of course is missing the entire point of the comic which is referencing Reimu's special ability in Touhou which is "the ability to fly through the sky"
Not only of this comic being a random funny "Yukkuri doing some crazy shit to fly" but also what Reimu's power really is.
She has the damned power to FLOAT, which basically the works explains is "To float out of reality" aka something like astral phasing or some shit like that, which makes her be untoucheable if she uses it.
you sounded more like this being more related to the original reimu and mistaken her special ability for something that technically everybody in gensokyo and their mothers do if they aren't from the human village.
Besides you also missed the point of SUN's comment on which he basically was using a serious studies approach for a funny comment pointing out how ridiculous the whole thing is.