Well, just to be sure, there are NO capture quests in MHF2, most are hunteing quests (kill or capture) so you never need to capture anything.
If you must there are some things i like to do.
First bring the 8 tranqs, but also bring 8 bomb materials and 8 tranqualizers to make more bombs. Then bring a shock trap, 2 genprey fangs and two trap tools.
Steps:
1. find the wyvern
2. beat up the wyvern
3. continue step 2 untill it is weak enough (read on for signs of weakness)
4. get it into a trap (i prefer shock traps for two reasons. One, they work anywhere, cept in your base camp, and two, they work on more wyverns than pitfalls do.)
5. Throw the tranqs (only 2 are enough, if it doesnt sleep, its not weak.)
To capture a wyvern (we'll use rathalos for example) you need to recognize when its weak, limping, behavioral changes (possibly), tactical changes, and locations are all giveaways at its strength.
Limping - Self explanitory, the wyvern will limp. (a limping akantor is the most satisfying sites in the world)
Behavioral changes - Any change or alterations in the wyverns attitude, diablos for example, will enter rage mode very, very often when it is at about one-third health, then stop, then it is very weak. Sleeping is also a behavioral sign of weakness.
Tactical changes - im still trying to find diffinitive proof of this, but one idea i have is when fighting certain wyverns, they seem to have a tendancy of useing more ranged attacks the weaker they are. NOT CERTAIN, STILL TRYING TO PROVE.
Location - Even if a wyvern does not sleep, some wyverns have a "home location" that they flee to when at low health (rathalos will head to area 5 in the forest and hills).
It is good to know what all the wyverns home locations are for every zone, cuz if they do go to sleep they regenerate health at an alarming rate, about 3 hp per second. (3 hp/s doesnt sound like much, but realize that a triple pound with a hammer does only about 150 damage, and most wyverns have around 5000-9000 hp)
*PLEASE NOTE* These signs are what to look for, BUT there are two exceptions to these signs, which may provide a false reading of their damage.
False sign - Lets say you see the rathalos heading off to area 4 in the F&H (this is waht i call a marker [a hint or indication of the wyverns next action} The rathalos usually goes to area 4 before he heads to area 5) You think you'll get ahead of it and run to area 5 to set up a trap to capture it. So you go to area 5 while it is still in area 4 and set up or a capture, but 10 min later you go out and find that it is in area 9 doing the wyvern things it does.
Fakies - These are harder to detect, but you will get good at knowing them.
EX. You beat up the rathalos and see it limping, BUT it still may have too much HP to capture.
Usually, the best thing to do is wait untill the rathalos starts to flee back to its base area to sleep.
Another useful skill to acquire (in life, not in the game) is the abillity to guesstimate the amount of damage you've already dealt. For example, It takes you 15 mins to kill a rathalos and you are already on the 20 min mark, its probably weak (this is estimating) If you kill a diablos in 20 min, and you are on the ten minute mark, its very likly that it is not weak enough.
Finally, when you THINK they are weak its never harmful to test it out. What i do is throw 2 tranqs at the wyverns while it is NOT in a trap, and if it doesnt go to sleep, its not weak enuff. If it does sleep, then place a trap under it and throw 2 more tranqs.
If you run out of tranqs or traps, just kill it and try to capture it next time.
Also, a quiick fyi, in my opinion, its not worth captureing. The amount of items you get is slightly higher, and your chance of getting rarer items is only slightly inreased. If you dont have any problem with slaying, just do that. Btw, WELCOME TO SUPER CHEATS.