For the tiger skull and mammoth you both have to go to the tundra
See picture below

From there it is easier to go find the tiger skull first because for that there are no special requirements besides dragging all the cubs along.

I stumbled upon it accidentally so I cannot tell which way is the fastest , during the search I got a lot of encounters with wolves that killed all of the cubs or there was a shortage of food ( or bad rabbit hunting skills that I dont want to admit) so adviced is to wait till the cubs are older or have left the mother. Go to the spot marked on the picture and you will find the skull inside a cave , best is to stick close to the wall so you wont miss it.

Just like the Tiger skull you have to go the tundra.
The requirements for this collectable is that it has to be winter to get to the mammoth
If you find it before winter you can sit and wait around untill the lake is frozen to get to it..


There are no places nearby to jump on to escape wolf packs , and just like with the tiger skull in that area I had diffuclties finding food for the cubs

The location for the fox skull is close to the mountains near the border

There you will find the fox skull , It can be hard to find but if you stick close to the wall you will get it

The blue feather collectable is close by the den near a near a small rock around this area.

The pink flower can be a little bit tricky because it is on higher ground and you have to jump to get there
That is the place where the pink flower is located
When you go to that area you have to look for a place you can jump , if you stay close to the wall and around the entrance you will find it
This is what you will look for


And at the tree you will find the pink flower

The location to the rose has the same requirement as the mammoth tusk , it has to be winter so the lake will freeze over so you can get to it.

The rose will be around the area with the three trees.
it will be a island in the middle of the lake thus only accecable during winter.

You will find it standing around this place

The pink feather is in the same area as the Rose , but it doesn't have to be winter to get to it , It is easier to move around during winter because it is a area with a lot of water and around winter is will be all frozen so you can move more freely.


The pink feather will be around this area , when you find the tree's looking like a bridge you will find a small path under it leading to a cave , in the cave you will find the Pink feather