Monaghan is Barnell, not Beak in Wolverine film.

This was an easy mistake to make I guess, I am assuming the source just got a little confused.

The reason for this is that Barnell was once a mutant called Beak.

Turns out (for the film) Barnell is a character from Wolverine's past who has the power to manipulate energy and electricity.

Barnell in the current comics is going around under the name of Blackwing with the New Warriors team and can also fly due to a powered suit he wares.

So, easy mistake to make, though it seems like they have utterly changed the back story and character for the film.