yes bruno, the carrion crow will only have one nest in a tree, a family of them will keep to an area but during nesting time will fight like mad, if u disturb them in nest on eggs they will leave, (u cannot do this by the way it is ilegal so I would never think of it) I remember as a lad (going back a bit) watching the firemen shifting the nests with there hoses, this was an annual thing, it was the rooks of course which had dozens of nests in each tree, not like the carrions, a lot of people think u can shoot crows but u cant u must have a licence to do so, u can frighten them with one of those lazer levels u get put the red lazer up to there nest in the dark it gives them a fright, or so they tell me as i have never done that, i read it some place!!!!