Naughty aliens. Naughty little bird children, the spacemen are going to give you such a spanking.

The description:

One thing’s certain about the exploration of outer space — there’s not going to be two worlds alike! In this new collection of interstellar explorers, the fertile and original mind of Eric Frank Russell presents a half-dozen of the more extraordinary possibilities.

There’s the world where everything moves at a pace so different from ours that it would take a couple of lifetimes to establish communication. There’s the planet of immortals, with all that that really signifies. There’s the puzzling problem of keeping important messages secret when surrounded by truculent aliens. And there’s more…

I'll bet those are the truculent ones. The spaceman looks so tired of dealing with these little bastards.