This is not so much a don't as I would do it again, but a warning that i wish my vet had given me. . . maybe it will help you all.
I have three cats. Two mellow and tolerant little anomalies that do not mind traveling (and don't complain that much about baths either!) and number three is a little more temperamental. Typically this is the cat that does not shut up for entire car rides.
So since i am a weirdo and like to travel with cats and asked my vet his thoughts on sedating cats and if he would ever prescribe a sedative. He had no problem with sedating a cat for travel and said just use Benadryl (he recommended a dose. . . said twice that would not hurt the cat at all i gave 1/2 his dose. . . so yes i was careful - and the vet did ok it and even recommended it)
Well he did not happen to mention a certain side effect. . . on that luckily i did encounter online so i was prepared. . . had i not read up on it. . . well travel plans would have been canceled so two crying idiots could rush kitty to the vet
Anyway we gave him the dose. And the cat proceeded to grow a 3-4 inch long Santa Clause beard of drool/foam. I had read that they can foam at the month due to their perception of it being bitter - but this was insane! it was an instant Santa Beard, he would then shake it off and grow another within moments. . . he likely grew 4 before it stopped. My guy and i cracked up and really kicked ourself for not getting a picture of this cat sitting perfectly sill and upright glaring at us with a beard. He did not seem in distress at all. . . . just sat there with a beard.
So if you ever give your kitty Benadryl. . . fair warning.
FWIW. . . it worked wonderfully. Within a few minutes kitty was sleeping peacefully, but still wakeable. He fought a little at being leashed and being put in the carrier, but far less than usual. He meowed like 10 times in a 1 hour long drive - took a nice long nap at out destination, and was perfectly happy to snuggle me in bed that night - last time i traveled with him he would not come out of the bed. . . this time he was friendly - even with strangers which is rare for him. . . i think he managed to sleep through most of the stress of the car ride and then just did not care as much about his destination. We did not do it on the way back for a comparison. . . yowled the whole way home. The other cats were good too, but they kinda always are.
Ohh and just because you have had five or six cats that were too dumb to know there was a bird in their house. . . . don't think all cats will continue the tradition. And don't assume that a cat will realize eating a bird bigger than it is likely not going to work so well.