Chimney pot designed with a Jackdaw nest in mind.

Hi,

The house I live in has always had a pair of Jackdaws nesting in one of the unused chimney pots.  I would like to seal all the pots up now as we don't use any of them BUT I don't want to evict my feathered neighbours.  I have spent an exasperating few months trying to find a solution to my problem.  I naively thought someone would be out there making and selling chimney pot toppers with an integrated nest!  Does anyone know of such a thing?  Can anyone suggest a suitable alternative?  Thanks