Birds have legs and feet, they stand. When birds fold their legs and put their breast against a surface, we can say that they sit, as in "a bird sitting on a branch". However, ducks lie on the grass. Spanish has the verb "posar", which means to rest softly over a surface. Maybe Spanish approximates Swedish more closely.
Would it be completely wrong if I were to accidently come out with "det är en fågel på taket" in a conversation? or is it definitely more natural to use "sitter"?
Is it also acceptable to use "finns" and "står" here?
Also, if it was say a cat on the roof, and it was moving around, would you still use "sitter"?