Yes, that's bad about him trying to climb the fence. That would worry me, too.
Meanwhile, to keep him sharp, you can have training time once a day. Either teach him something new, or put him through his paces. You can break a biscuit into small pieces, so that his treats don't add up to much.
And, when doing that, maybe reinforce his recall.
Do you use a particular word when you want him to come to you? We literally tell Krypto to come, though we can just say his name and he will come.
You start in the house. Wait until he settles somewhere, and then say his name, and come, or whatever your word is. When he does, tell him how smart he is, and give him the piece of treat. You can then have him sit, lie down, or whatever he already does. Just to keep it from being all about him coming to you.
Do it randomly, whenever you think that he's not expecting it.
Then, when he's 100% consistent, try it outside when he's not that excited about deer, dogs, or people. Call him back to you for no reason at all.
Eventually, his recall should be strong enough that if you see a problem, like the fence, that he should come to you immediately when you call him to you.
I hesitate to use treats, in one way, but it's good to reinforce things for a while, then can be phased out if you like.
Krypto is so praise oriented, that I only use treats for 'official' training sessions. I could get by without them, but it works so well with the method that I use, that I use them just for training sessions. All the rest of the time, he does what we ask with no treats.
In fact, he really doesn't consider the popcorn - air popped, nothing on it - food. When I first started with it, our 4 minute training sessions took forever because he'd lie down with a single piece of popcorn and gently shred it. Oh, brother!
Now, at least he just eats it normally, so that we can move along.
I really pushed his recall. If anyone even called his name, I said that they needed to make a fuss when he came. The guys thought that it was over the top, but I assured them that, if they wanted him to still come when called when he reached the stage of not listening as well - now, then they had to make it super strong, as in every single time.
Now, even though he's in that 'I can't remember what you taught me' stage, things like sit and come are not affected, because we worked on them all the time.
If we tell him to come, he does so at a trot to a run, looking like he just won the lottery, and all he gets are happy words and mega pats.
Also, do you have a thin, not overly long, leash? Could you put it in your back pocket? I was just thinking that it might be more comfortable than walking Charlie by holding his collar? And, better on your shoulder if he yanks the other way for some reason, such as a deer coming out in the open?
Yes, that's sad about the sparrow, but you're right about other critters eating.
Wow, you did have a critter morning! What great bird sightings. The hummers, doves, vultures, etc.!
Toadstools, yes. Now that we've had rain, I'm worried about a certain pup, who currently puts everything in his mouth, getting one of those in his mouth when he pulls a weed or grass.
I hope that the rest of your day is lovely!
Love All Life; Thank You For Posting! :)