It's a bit of an age thing but I'm surprised it hasn't happened before now
. It's likely he's learnt this fantastic new sport from his holiday mates and can't get enough of it at the moment - kid in a candy shop.
It's no bad thing because to be honest, sooner or later he would have discovered his nose but you are going to have to work really hard on his recall now and also put that nose to work so he starts to use it in a controlled way (controlled by you)!
For recall don't call him when he's on a scent at the moment it's a waste of time, but practice where you know he's likely to come to start off with.. If you haven't got a whistle, you'd do well to get one as dogs hear them a lot more than voice when they're hunting and start to teach him to recall to the whistle (I use 3 pips for recall but decide what you want to do and then stick to it) and reward like mad with very high value treats (roast chicken is the ultimate here but he might be more motivated by a ball - work out what he really loves) every time he does a good, quick recall - this will get him into the habit and will help when there are more distractions. To get his nose focused on tasks for you rather than hunting for himself, you could get a gun dog dummy or even a tennis ball would do and start hiding it for him to find - do this at home and on walks...
There are loads of threads on recall and ways you can work on it, if he gets really bad you might consider a longline and harness for a while for example, so if you do some searches on here you'll get loads of info and probably quite a few happy ending stories to help keep you sane
Good luck!
