Netting but must be done right.
If you have any doubts pass, check out recent lawsuit in CA where netting was installed and caught a few swallows.
Lawsuit and fines for the contractor and the d.o.t.
Netting is the most common method used many dot's do it themselves with their own crews.
No other deterrent is proven for these situations, audio and other visual deterrents won't stop colonies with affinity for the structure.
This is something we have experience with and have explored at great length with various state/fed entities.
Just beware of pitfalls.
Justin
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Swallows are already building here though we are south of you, I expect yours must be arriving soon. Is the contractor they mention the bridge builder? If it is they can't allow nesting either as any eggs/adults/chicks killed result in that federal action. I know of others who have been paid to keep nests scraped while maintenance or replacement of these structures was going on to prevent "take" and fines.
Would be an expensive net job for 15 days worth of action. Someone was likely asleep at the wheel on this one or failed to get the ducks in a row. Often if they can't block a biological species of concern they have to delay.
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Last edited by HD_Wildlife; 04/30/14 01:52 AM.