My 13 year old daughter has a 2 year old border collie. I am divorced from her mother and did not live in the house when the dog was adopted as a puppy. The dog always barks excessively when I am in the house or yard. Over time, I’ve managed to get the dog to come to me and I am able to pat it and I’ve brought a dog biscuit with me for it as well when I visit. I can pat the dog for half an hour but when I go outside the dog still is aggressive and barks at me. Why is my dog aggressive? Is it because the dog doesn’t like it when I take the kids away?
More likely than not is that it’s not just you. See if the dog spends time looking out windows or is left alone in the yard. Your noticing the dog’s switch flips indoors vs outdoors makes me think that’s the most likely. The dog is now at the age where a history of confinement combined with visual access to activity outside often leads to territorial aggression. It’s also around this time that many dogs cross over from just barking to snapping or biting. That’s when we hear,”Oh my, he’s never done anything like that before.” which I think is “dog owner “speak” for, “Whoo-wee! We’re usually a little faster than that! Sorry, I’m sure that’ll heal with out leaving a scar. You’re right handed I hope!” If this is a territorial aggression problem left unaddressed, it will get worse. so have a chat with your ex as I’m sure neither of you want your daughter to lose her dog if it bites someone.
Another possibility is that your departure and arrivals are from the dog’s perspective unusual compared to others. If your kids are over the moon in anticipation of their daddy’s imminent arrival and are more physically demonstrative then they are when others visit that might rattle the dog a little. On the flip side there may be a negative vibe created in the house due to past or current tension and/or drama but you’re situation is probably much like that of most of us ex-husbands where our ex-wives look forward to our each and every visit.
If the dog is the way it is because for the window/backyard reasons an investment will be need to be made in some rehabilitation training plus some environmental changes. If it’s because the dog thinks you’re throwing the house’s feng shui out of whack you can try a few things. Giving the dog a biscuit is not a bad idea. Ask your daughter though if there is some other thing the dog enjoys like a ball being thrown and every time you have to cross into the dog’s red zone toss the ball a few times. What would really help is if you could do make more frequent visits as if this is an every other week scenario it can be hard for the dog to connect the dots. Something else is to have your daughter put a leash on the dog before you come over. A really long one if the dog is going to be with her outside when you arrive so you take the handle end smoothly and then head out for a short walk, with your daughter. If it’s feasible you might connect better with the dog if father and daughter were to sign up for some dog training classes together.