"...in Australia where they are now a food source to the aboriginal peoples because they have killed off so many of the small native animals including rabbits and such"
Rabbits weren't native to Australia either.
"Let's just say I have a bucket of some corrosive chemicals left out, for specialized cleaning purposes or whatnot. If a small child were to come onto my property, dip their hands in the bucket, and suffer chemical burns, should I be reponsible for having left the chemicals out or should the parents of the child be reponsible for not keeping an eye on him?"
Well, it does depend on the details of the situation, but it is very likely that you would be found to be at least contributorily negligent, and you could end up on the wrong end of a civil lawsuit, or possibly even charged criminally depending upon how the police viewed the situation. I think part of the question would be the details of 'left out', and just how nasty the stuff in question was.
"If it were kids next door to me who lose their ball or frisbee in my backyard, they should be familiar enough with me to know what I may have going on in my backyard, and know whether or not I would find it acceptable for them to be in my yard. If they don't have that level of familiarity, they should be ringing on my doorbell to ask my permission."
"All I'm saying is one should be allowed to have whatever they want in their backyard. "
This is only true so far as the laws of the land allow. Generally, there are quite a few restriction on what you can actually do in your backyard. Check out your municipal zoning by-laws if you don't believe me. No as for the setting of traps, I believe that is a provincial issue.
"This would include poison/traps for cats. It would be ethically wrong, but it would be within the property owner's freedoms to do so. If something goes wrong because of someone or something trespassing, the trespasser's parent/owner should be the one at fault, not the person exercising their freedom to use their backyard for whatever purposes they see fit."
Not according to the law in Canada. If a child enters your backyard and drowns in your swimming pool because you left the gate unlocked, you're in big trouble. If you set traps and injure or kill the neighbours cat, dog, or child, you would not only be civilly liable but could go to jail for cruelty to animals, negligence causing bodily harm, etc. If a burglar enters your home and your dog/cat/nile monitor/death adder bites him, it is entirely possible that he could sue you successfully.
Here's some details specific to Nova Scotia, but I think that Ontario's Occupier's Liability law is very similar.
Apologies for thread hijacking:-)
"In Nova Scotia, the law with respect to this issue is covered by the Occupiers’ Liability Act, and to a lesser extent by the common law.
The Act basically sets out the duties owed by an occupier to persons entering upon their premises. The term "occupier" includes a person who is in physical possession of the premises or has responsibility over it. An occupier may also be someone who has control over either the condition of the premises, the activities that take place or those persons allowed on the property. The "premises" includes land, equipment and fixed structures, water, ships and vessels. It also includes portable structures (trailers) so long as the structure is designed or used for a residence, business or shelter.
What duty of care do occupiers owe?
Under the Act, the occupier owes a duty to take such care as is reasonable in all the circumstances to see that each person entering on the premises is reasonably safe. The duty is in respect to the condition of the premises, activities on the premises and the conduct of third parties. For example, if you host a party and one of your guests falls down the stairs as the result of a missing step, you may be held financially responsible for their injuries.
What can be done to discharge the duty?
In deciding whether an occupier has fulfilled his/her duty, the courts will consider a number of factors including the age of the person entering the premises or that person’s ability to appreciate the danger (for example, we owe a greater duty to children), the efforts made by the occupier to warn of the danger or to discourage persons from entering the premises (signs or fences), whether the occupier knew or ought to have known that the person was on the premises, and whether the risk was something against which the occupier should reasonably have been expected to provide protection.
What about trespassers and thieves?
The duties discussed above do not apply where the person entering the property willingly accepts the risks of doing so. The Act provides that a person is deemed to have accepted the risk where that person trespasses upon certain types of land including (among others) land primarily used for agricultural or forestry purposes, vacant or undeveloped rural land, recreational facilities that are closed for the season and roads that are marked as private and blocked by a gate or other structure. Persons entering upon the premises with the intent of committing an offence under the Criminal Code are also deemed to have willingly assumed the risk. In these cases, the occupier owes a lesser duty not to create a danger with the deliberate intent of doing harm to the person and not to act with careless inattention as to the presence of the person. Accordingly, we cannot go around setting traps inside our homes with the intent of injuring or harming a would-be burglar, nor can we simply choose to ignore the fact that trespassers are entering our property and fail to take reasonable precautions. "
Excerpted from http://www.daleydemont.ns.ca/pages/occupiers.html