Think in layers: no single barrier stops all three
Cats, rats, and sparrowhawks attack an aviary in completely different ways, so security has to be layered. A cat works at ground level with paws and patience, a rat gnaws and digs and squeezes through gaps that look impossibly small, and a sparrowhawk strikes from above at speed. Doves make the stakes higher because they panic-flush rather than fight or hide, and a dove battering itself against mesh fleeing a hawk it can see can be injured even when the predator never gets in. Each layer below answers one of those threats.
Mesh: gauge, doubling, and the gaps that matter
Use small-gauge welded mesh, around half-inch square, rather than chicken wire, which rats chew and cats tear and which flexes enough for a paw to work through. Half-inch mesh excludes rats and mice, stops a cat's paw reaching a perched dove, and denies a sparrowhawk any purchase. Double-mesh the walls where cats patrol, with the second skin set a few centimetres outside the first, so even a reaching paw meets air instead of bird. Check corners, door frames, and the junction with the roof for gaps, and fix mesh with proper fixings rather than loose staples a determined animal can worry out. Any rusted or damaged panel gets replaced, not patched with cable ties.
Roof and the sparrowhawk problem
A solid roof over at least part of the aviary, ideally the shelter end, gives doves a zone where they are invisible from above, and full mesh roofing elsewhere must be the same small gauge, taut, with no sagging sections a hawk's impact can bow inward. Sparrowhawks also hunt by flying at an aviary sideways to flush birds against the mesh, which is another argument for double walls and for planting or screening that breaks the hawk's line of sight and the doves' view of it. Perches placed away from the outer walls give flushed doves somewhere central to land instead of clinging to the mesh within paw and talon reach.
Ground level: rats, digging, and feed discipline
Set the aviary on a solid slab or concrete base, or bury mesh vertically and outward in an apron below ground level, so rats cannot tunnel up inside. Store feed in sealed metal containers, feed measured amounts, and sweep spilled seed daily, because an aviary that feeds rats nightly will always have rats testing its defences. Keep the perimeter clear of dense cover that lets cats and rats approach unseen, and check the base line weekly for fresh digging or gnawed timber, which tells you pressure is building before a breach does. Timber frames should be protected where rats can reach them, since a gnawed corner post hole is an entry point in waiting.
Doors, latches, and the dusk lock-up
Fit a double-door porch so no dove slips out and no cat slips in while you enter, and use latches that need two actions or a clip to open, because cats learn simple bolts and raccoons of the bird world aside, even a determined cat can lift a basic catch. The strongest daily security habit is shutting the doves into their solid night house at dusk, when rats and cats are most active, and letting them into the flight in the morning. That routine only works if it never gets forgotten, so KinsLe Care Teams can carry your doves' dusk lock-up, morning release, and weekly perimeter check as assigned duties, each marked with a timestamp when done.