UKC

There are jackdaws nesting in Forked Lightning Crack (E2 5c), at least two in the crack itself and one in the exit chimney.

Is the message here "avoid climbing this route" or "watch your fingers, the young ones will try and eat anything that moves" 😁

Jackdaws should be fairly tolerant of disturbance, the risk is that on a cool day the eggs or more likely now chicks get chilled by the parents being away from the nest for too long.

Given it’s a criminal offence to intentionally disturb a nest, having read this post as you will have the message is quite clearly ‘avoid climbing this route’. Doesn’t matter if they’re tolerant or not, you have been forewarned.

I've always felt terrible when I've accidentally disturbed a nest, even when it's pigeons who clearly don't give a fudge.

Yes I know, was just being flippant from previous experience of being halfway up a crack and discovering youthful jackdaws.

Forewarned (as in the OP)  is obviously a different matter.

No, intentional disturbance is only an offence for Schedule 1 species, of which Jackdaws are not. Disturbing a Jackdaw is not an offence.

The relevant legislation reads: 

All birds, their nests and eggs are protected by law and it is thus an offence, with certain exceptions (see Exceptions), to: 

• Intentionally kill, injure or take any wild bird.
• Intentionally take, damage or destroy the nest of any wild bird while it is in use or being built.
• Intentionally take or destroy the egg of any wild bird. 

For Schedule 1 (for climbers, most likely crag nesting species are Peregrines, Eagles, Chough, Barn Owls) this is elevated to:

• Intentionally or recklessly disturb any wild bird listed on Schedule 1 while it is nest building, or at a nest containing eggs or young, or disturb the dependent young of such a bird.

https://www.rspb.org.uk/birds-and-wildlife/advice/wildlife-and-the-law/wild...

Jackdaws commonly nest at Trowbarrow and it's not unusual to have them flying in and out of the Main Wall classics while they're being climbed. I have heard of them 'trundling' the odd stone. They do have a mischievous look about them.

They are probably highly intelligent like most corvids, I wouldn't put it past them to "creatively" defend a nest.

Legalities aside, I wouldn't feel particularly good about disturbing any nest whilst climbing. Even fulmars...

Since I endured a thorough spanking on Thin Red Line (E1 5b), I'm quite happy to leave FLC until later in the year.

As commented in the other thread, you can damage a nest by disturbing the adults enough that they do not return. The nest would fail and therefore result in being damaged. If you’re confident enough that they will return then by all means, go for it. On your conscious be it.

Translation ; I'm wrong so am resorting to moral arguments rather than legal ones. 

Not really. Pointing out the law does not differentiate in the type of damage, a failed nest due to disturbance is a damaged nest. Even if the passing climber didn’t touch it physically. Therefore if it’s known there’s a nest there and you carry on anyway, good luck. Which was the moral bit.

I refer the thread to…

https://www.mountaineering.scot/assets/contentfiles/pdf/nesting-birds-Guide...

...in particular…

“It is not an offence to disturb most birds, although it is an offence to interfere with the actual nest or obstruct or prevent any wild bird from using its nest.”

Knowingly disturbing a jackdaw at its nest is obstructing it using its nest and changing its natural behaviour. It’s an offence. 
What might not be an offence is climbing a route further along, and not denying the bird access to it’s nest. Still a shit thing to do though. Sorry for the morals.

BMC source, if it’s even required..

https://www.thebmc.co.uk/nesting-birds-advice-for-climbers

”All wild birds, their nests and eggs are protected by law (the Wildlife and Countryside Act 1981 and the Countryside Rights of Way Act 2000). Damaging, destroying or disturbing the nests, birds or eggs is an offence.”

Eh? So climbing a route without a nest on is also morally wrong? Deluded nonsense

If by doing so you're disturbing birds on neighbouring routes, then yes.

The only deluded nonsense in here is the thinking that your ‘right’ to fun overrides the right to rear offspring in peace. It’s really not difficult to avoid known nesting sites, there’s thousands more routes on hundreds of other crags to keep you busy. But if you’re insistent on knowingly barrelling through a nest because you don’t think you’re on shaky ground legally speaking then like I said, you go for it. I noticed you haven’t called out Mountaineering Scotland and the BMC for being wrong on the matter? 

yes, maybe an extreme example but there was a cat that got up to the wood pigeon nest in my garden and disturbed the next and broke an egg. i replaced remaining egg and after briefly returning, the nest was abandoned;(