When I uncovered the birds this morning, Leo the cockatiel was on the bottom of his cage. It took monumental effort on his part to pull himself onto the lower perch, where he had to spread his wings to balance, unsteadily at that.
I called the emergency vets' office up in Huntersville, assured them he'd been perfectly normal until this morning, and found out that the avian vet would be in at 8, which gave me just enough time to get there same time as she did.
I'd decided on the way that it had to be his kidneys; all the evidence--Ezra's chronic kidney disease, Claudius's passing of crystals last month (turned out he didn't have a uti after all), even my son's suspected passing of stones/crystals back in March--everything pointed in that direction.
Blood work showed I was right--Leo's uric acid levels were in the 50s. Because Leo flew into my in-laws' garage several years back, we'd never known how old he was, but the vet thought he was already in his 20s, "a little old man with gnarly, gouty feet." Because of his age, because he'd been too old to tame by the time we got him, because the vet said she'd never had the luck treating cockatiels with kidney disease that she's had with conures, we agreed it would be best not to put him through the effort.
So I brought the cage back empty, with Leo inside a green cardboard box.
We will miss Leo's dancing--an activity his gnarly feet never curtailed. We will notice how much quieter the house is without him.