/ Walking access
Most of the coastal crags near Swanage are going to be closed for birds starting from March. Does that hold for climbing only, or is it about overall presence of humans in the area? If I want to go there for a walk and make pictures of the coast and possibly birds would that be fine?
Bird bans on seacliffs don't normally affect walkers as the birds nest away from the paths (generally at the top of climbs where rock gives way to vegetation).
I've just looked online at the OS maps for the Swanage cliffs and it looks like it's pretty much all CRoW access land. That means you can be there all the time except I think for a maximum of 28 days if the landowner wants to do something (round here that usually means grouse shooting - unlikely at Swanage!). Also, it seems like the South West Coast Path is running along the cliff top and that's a public right of way which you can walk at any time of the year. The bird ban will almost certainly apply only to the cliffs themselves plus any of the high angle soil above which the birds might want to nest on. So long as you don't encroach on the cliffs and disturb the birds then you'll be OK. I would think that RSPB or BTO would probably put warning signs up saying which bits should be avoided.