These are just outstanding! Is it rude to ask what kind of coal and paper you use (and what format?) The birds have details that I haven't been able to make with charcoal myself.
Not rude at all, Oivind . . . we're all here to try and learn from each other.
I use heavy gauge lining paper (wall paper) and various thicknesses of charcoal - from 2cm diameter to 3mm. Very sharp edges are easy to make (if required) by scribbling on card with the charcoal. I use a Mahl-stick a lot when working on big charcoals.
Most of my charcoal paintings are 33"x22", so what may look like very detailed areas of work may actually be quite sketchily drawn - but the reduction in scale for the computer screen will obviously tighten the work up somewhat.
I've been asked by a couple of people about my charcoal painting techniques, so I thought it may be best illustrated by showing a step-by-step process of a piece of work. There are occasional detailed images which show bits of technique such as lifting off drawn areas with a putty rubber, or blending some patches with bluetac.
If there's anything unclear, or you want to ask anything about the process, please don't hesitate to ask.