It is always a good idea to brush up on your dog’s recall skills, and work on training your dog to enthusiastically come when called. Having a reliable recall is not only imperative for safety reasons, but will allow your dog to enjoy more freedom if you can trust him to return when called.
From your dog’s perspective, there are many enjoyable things to do outdoors instead of returning to you when called: sniff around, eat things found on the ground, chase squirrels and birds, go play with other dogs… Unfortunately, we seem to call our dog back only when he is engaging in these activities! No wonder he is reluctant to come when called, if it means losing the opportunity to have doggie fun.
As well, we often inadvertently “train” our dog to not come when called. When we repeatedly let our dog have the opportunity to be off leash and continue to do his own thing when we call him, he is able to access his own rewards from the environment, and is being rewarded for not coming when called. The dog quickly learns that we are unable to control these situations, and that he does not need to return to us to be rewarded. This is another case of practice makes perfect—the dog learns that it is more beneficial for him to ignore you, and this strengthens the behavior of not coming when called.
Remember, when the dog is off leash, his actions are 100% of his choosing. We always want him to be motivated to come when called because there has been a strong history of the recall being generously rewarded. If he has learned, historically, that the end result will not benefit him, he simply will not come when called. This explains why many dogs do not want to return when called if they will then be leashed up and taken out of the park, crated indoors after returning from outside, or roughly handled or restrained. As well, it helps us understand why correction-based approaches do not work well for recall. Why would the dog want to be close to you if he is treated in an intimidating manner or punished when he returns?
If we expect the dog to be able to be successfully called away from difficult distractions, we need to put in the work/practice required. In the meantime, we need to make sure the dog is not put into situations where he will get to practice ignoring our recall, even if that requires us to keep him on leash. Most importantly, we need to build a solid history with multiple repetitions of the dog being generously rewarded for recalls, working at progressive levels of difficulty. We need to practice and set up situations to work on recall, rather than just hope for success in naturally occurring, distracting situations. A dog training class specifically designed to work on recall skills can be a fun way to practice with your dog, especially if offered outdoors, where you can work with real life distractions.