Well, my pond does have a sloped edge, and i even put ramps and little floating houses so in case the birds went in they could get out easily. But, the birds didnt even try. It was one of the most pathetic things i have ever seen, the birds would all be flying or running from one side of the aviary to the other, and when they hit the water they would just kinda flop on their side and slowly sink, never even making an attempt to save themselves. It was the weirdest thing. The three that survived the pond where the only three that would even try to get out of the water. I would think the garden border might work, but the birds kept flying into the pond as well, so it wouldn't solve that problem... I have ducks and pigeons in the aviary now, no quail. But, quail would be a nice addition to the aviary. But i just dont want another mass drowning. Lol.