In reply to mpickering:
Even without one of the nests being around Jackdaw Grooves I would have guessed that these are jackdaw nests - almost certainly will be if they're "large bird's" nests.
If they are jackdaws then the major risks are:
- Eggs going cold because parent bird not sitting on nest
- Chicks (especially very young) getting cold as above
However this is most likely on wet cold days - which means less climbers so less possible disturbance. On warm sunny days it's less of a risk - they can cope with longer (but not long) absences of the parent birds.
I'm not saying ignore the "restrictions", far from it, just that Jackdaws are pretty hardy birds and will usually tolerate being fairly close to human activity - much closer than Ravens or Peregrines.
So if on a warm day you find yourself climbing past a jackdaw's nest that you weren't aware of, just press on and get past as quickly as possible, and if the route involves deep hand-jams, don't be surprised if you get a peck or two from youngsters thinking the wiggly things are food 😁 (Venery (HVS 4c) in Dovedale)