Choices

[sexobon]

If entertainment is your priority, you could choose the weed, rifle, mirror and hand saw. Then get stoned and do some over the shoulder trick shooting using the mirror trying to hit the saw blade to make it sing.

[glatt]

Giving this serious thought, water is the biggest issue on all the small islands I have been on. Fresh water either doesn't exist or is so nasty that a purifier or boiling would do nothing. The tarp would let you collect rain water and you need a pot to put it in. Matches to get a fire going to try to distill salt water out of the pot, onto the tarp and maybe drip into your mouth. The only realistic chance at survival is getting rescued and a mirror is best for that because it will work for years and over great distances and a flare gun will only work if somebody is looking already.

[sexobon]

The tent material can be used much like the tarp for obtaining water and makes for better shelter at night. Sink part of the tent floor into a depression in the ground and it will hold water away from contaminants.

[sexobon]

The OP doesn't say the island is in saltwater. I'm working from the premise that fresh water is available either around; or, on the island otherwise the water purifier wouldn't have been offered as a choice. If there's no fresh water, you have only 3 to 5 days of useful function; so, you may as well opt for all the potential signaling devices. That is unless you're really good at rain dances.

[glatt]

I don't want to be on a deserted island with only four of these items.

[glatt]

I would die.

[limey]

Tent, pot, mirror, knife.
I was going to go for tarp as roof and water collector, but UT is right, tent will also collect water and has handy guy ropes ....
Pot for water purifying/cooking
Knife - because I'm more like to find/trap small mammals/fish/birds so knife to kill/prepare.
And mirror because I'm vain. No, because of signalling and starting fires ....

[sexobon]

I saw that.

[xoxoxoBruce]

How do you start a fire with a mirror?

[limey]

Originally Posted by xoxoxoBruce

How do you start a fire with a mirror?

Pile up some kindling and use the mirror to focus sunlight on the pile.

[xoxoxoBruce]

Yes, but that's a special type of mirror, a normal mirror won't do that.

[Carruthers]

Originally Posted by limey

Pile up some kindling and use the mirror to focus sunlight on the pile.

And another one...

Link

Late in the year as well.

[sexobon]

Makeup/shaving mirrors are magnifying mirrors with a concave reflecting surface that can focus the sunlight. Flat mirrors, like the one depicted in the choices, don't do that.

The optics in the rifle scope can be used to focus sunlight though (some disassembly may be required).

[sexobon]

Originally Posted by glatt

I don't want to be on a deserted island with only four of these items.

Originally Posted by glatt

I would die.

If you were one of the choices, a survivor wouldn't go hungry.

[glatt]

I took a catamaran out to Lady Musgrave Island as part of a snorkeling trip. If you look at photos of the place, it looks like a tropical paradise. But when you are there in person, it's a hot, dry, bird shit infested hell hole. There are plenty of fish and lots of birds. There are small trees to provide some shade. The ground is covered in sharp broken coral and shells. I spent most of my time there snorkeling on the beautiful reef, but the hour on the island was more than enough. So hot. The birds seemed like they would be easy to catch but I didn't try. They might have flown away if I tried to grab one. Is there enough moisture in a bird to keep you going? I read Unbreakable, and that guy survived without water for quite a while.