I wonder if falconry can fill that detection gap. Trained birds are already used to manage wild bird populations at airports. Now time to stop fake birds.
I read somewhere that the French government was training golden eagles to attack drones. I've been out fishing and when I had a bite on my line a couple of eagles flew half a KM from a nearby bluff to come check out if I had snacks for them, birds are all about the snacks!
I'm assuming the real birds would be way more expensive and at high risk of enemy actions against them. A bird bomb smaller than a shotgun shell would be enough to take the bird down if you're suiciding the drone.