great middle of the road pet for any hunter looking for decent DPS and the ability to take on 2 of it's own level at once.

Can't tank like a boar, but takes the same lvl mob out in half the time.

This is the lowest level pet to come with screech level 2. This makes it very good at holding aggro - even from muliple mobs, although it is a melee aoe effect and you may need to disable if crowd control measures are being used by other party members.
The last post is not really correct, this pet may have armor/stamina a bit less than a boar but it is much better at holding aggro from dps or healers, especially when taking on multiple mobs. Therefore it is extremely good at tanking - if you consider tanking to be mainly about aggro management.

I can't find the bird on the area mentioned, it's not Salt Flats Vulture available there but Salt Flats Scavenger and it have NO screech rank 2

The vulture is somewhat hard to find.  The is usually one flying around the area in the thottbot map.

If you want Screech Rank 2 I recommend getting it from this guy at level 32-34 if you dont you'll have to get it from a Shrink Bat ( In uldaman) at level 37-38 or wait until level 39-40 and get one from a Dread Ripper In Desolace

Info from http://petopia.brashendeavors.net/html/skills/skills_screech.php