The answer of course depends on many factors, but there's no doubt at all that they can be extremely effective. For the past several seasons the Environment Department in Guernsey has enabled ropes to be erected on Lihou island off Guernsey's West Coast, which has public access. These ropes are only in place for the nesting season (April-early August), but it is staggering how secure the birds feel provided people stay behind the ropes - as the photo below demonstrates!
Our thanks to Sure who have sponsored the provision of these ropes.
|Rope Protection for Nesting Seabirds on Lihou (c) PKV|