Aw, darn. What a shame. I'm sorry to hear that.
For future reference....
Often, you can start by putting a bit of honey on the side of the beak, where the upper and lower mandibles meet. Do this a few times and you'll see them sort of smacking their lips and licking it up a bit.
Sometimes, the extra blood sugar is enough to get them to start eating again.
You can do the same with some electrolyte solution to help combat dehydration. But personally, I prefer do to subcutaneous injections with Ringer's solution (plain saline can work too). I use a tiny insulin syringe.
If you couldn't get him eating/drinking on his own with those tricks, you could have crop tubed him. It's hard if you've never done it on a baby. The babies basically do all the work for you. You just aim the tube toward the bird's right side. You do the same with adults. Once it hits the back of their mouth, they'll swallow it. Then you just inject the handfeeding formula into the crop. If you didn't have handfeeding formula, you could use honey and electrolyte solution for the first feeding and baby food for the subsequent feedings.
When done right, there's no risk of aspiration since you're essentially bypassing the swallowing phase and putting it straight into the crop (assuming you don't over-stuff the crop, of course. That can cause regurgitation.)
But if you'd never done it before, it would be tough to know if you're doing it right on an adult. (Babies are easy since there's no feathers, the skin is translucent, and all they do is beg, so it's much easier to learn on a little one.)
Hope that helps for the future. I'm sorry this guy didn't make it.
I always get so nervous netting them, but sometimes, you don't have a choice.
Steve - reptile heating pads come in a few styles. I have one that sticks to the underside of a plastic cage bottom (or in the case of a reptile, the bottom of a glass tank). I used it for my hedgehog. You would just line the plastic cage bottom with a paper towel or similar and it would warm the plastic.
You could also theoretically place it inside the cage with the bird, but it would have an exposed wire that you'd need to cover somehow. And it would need a few layers of covering as they get very hot.
They also come as little faux stones that you could leave as-is or cover with something.
Most of the adhesive ones get very hot (hot enough to melt through the thinner plastic cage bottoms) so you'd definitely want to cover them with some paper towels or even some tight-weave fabric of some sort.
