Exactly how hard would it be to place a “cork in the hole” to render the cavity unusable? If (big if) overpopulation becomes a problem, it’s pretty easy - these days - to develop and maintain a database of most of these swift cavities, survey them from a distance to see if they are corked or not, and adjust the number of corks as appropriate to address current population trends.
I get that you don’t like the approach - but it’s a solid one, which is what works best for swifts’ nests: solid structures.
There’s kind of need for them everywhere and this is a pretty practical way to ensure they end up everywhere and will stay there.
And in 20 years, in the case of overpopulation, they would force people to search for those tiny holes in the walls.
I don’t like the approach. Reminds me of the story about China and sparrows.
Exactly how hard would it be to place a “cork in the hole” to render the cavity unusable? If (big if) overpopulation becomes a problem, it’s pretty easy - these days - to develop and maintain a database of most of these swift cavities, survey them from a distance to see if they are corked or not, and adjust the number of corks as appropriate to address current population trends.
I get that you don’t like the approach - but it’s a solid one, which is what works best for swifts’ nests: solid structures.