Doesn't list native species of song birds, sea birds or anything other than "birds of prey" & what in my bird book come under gamebirds, so if someone has one of them that can't be released (think I remember a story of someone having a puffin that couldn't be released so they kept it as a pet, might have been blind in one eye but I can't remember the reason) would they need to register? Or if they were rehabilitate & release centres do they have to register? With the speed of turn around in fledgling season they'd be filling out so much paperwork they wouldn't have time to care for the birds. Surely rehabs, due to taking birds in from the wild, are more exposed to (but also probably protected from due to initial vet trips) avian diseases been found in their "stock".
Finches (zebra, canary, etc) look to be the only unaffected (commonly kept) pet birds, so long as they're indoors not kept in an aviary.
I'm still wondering if I need to register my girls, or just keep them as indoor birds all their lives - mum's a bit unsure of having our patio caged in to an aviary type enclosure so we haven't looked into that yet. But if in order to have the girls sit out in the summer evening with us I have to register with someone who - in even the narrowest chance - could order me to have them destroyed, I have to weigh up whether I can stand even the narrowest risk of loosing them in order to give them that form of enrichment (granted one that's highly recommended) or if I'm going to stick with artificial UV light & other enrichment in the house instead.
Or another way around it, book lots of vet check ups, and take them for days out that always pass through a vet check up, then whenever you're out with the bird you're always on the way to / from the vet, no matter how round about the route is. (Just I expect vet check ups aren't "cost effective" for that.)