[santraginean]

Same. And it's much more descriptive than "a flock of owls" (the author's preference), given that owls don't flock.

[smt88]

Owls do flock[1].

I can't find anything defining "flock" as having more than a certain number of animals in it, so I would assume 2 owls would be a pair and 3+ owls would be a flock.

1. https://www.owlpages.com/owls/articles.php?a=2

[elygre]

And of course, two crows are neither a murder, nor a pair. They are a an attempted homicide.