The animals are doing a cute thing and given the context of the previous panels, that means something bad. The TV narrator gave the viewers some time to marinate in their suspicion before confirming (via disappointed nodding) that they should not find the bird sitting on a frog cute, but sad. The whole comic is a reference to nature documentaries. Where the events depicted in them are usually tragic despite the animals potentially being cute/endearing

The three were left to die, being abandoned by their previous social group. However they banded together and formed a music band. On their way to the big city they found an abandoned house and wanted to shelter for the night. Inside however were thieves and bandits, celebrating their latest heist. So the band of musicians stacked on top of each other, entered the home and each let out their most horrifying scream. Utterly befuddled and scared shitless of such an unknown three-headed creature, the bandits fled.

Now after having rested, the band of musicians is on their merry way towards the big city to earn their claim to fame.

Everything seems fine. However… Unbeknownst to them, they are now on the hitlist of one of the most dangerous mafia organisations of Bremen.

My interpretation is that those animals are engaged in some very kinky inter-species sexy time, and the narrator is shaming them for watching.

Sex is nice, I like it

I like in the HHG2TG Arthur Dent learns to speak bird and it turns out they’re just talking about barometric pressure and dew point.

so, like (a lot of) human music