In assessing negligence, what duty of care is owed by landowners to licensees?

In property law, a license is like a permission slip that a landowner gives someone (the "licensee") which allows them to enter onto the land and do something that does not involve the landowner. For example, if you owned a large plot of forested land, you may give your neighbor permission to come hunt on your land, or even just walk around and birdwatch. Whether or not your neighbor actually makes use of their license doesn't really concern you, all that matters is that when and if they do come onto your land, they are not trespassers.

The law appreciates your neighborly gesture enough that it doesn't expect you to go out of the way to roll out a red carpet for your licensee—after all, you are generously allowing someone to enjoy your private property. However, the law does expect you to give a licensee a warning of any non-obvious (concealed or otherwise) dangerous conditions that you know about.

In other words, the law doesn't expect you to walk every inch of your property before a licensee visits and take note of anything that might be dangerous, nor does it ask you to repair anything. All the law requires you to do is see something, say something. So that cave on your property that you noticed now houses a family of hungry bears? Give your licensee a heads up. That section of animal traps you set up and never cleaned up? Let your licensee know to avoid that area.