The tailor in Eldfell - City Center needs five firebird feathers to make a garment. Get them for him and you will be rewarded.
On the iPod/iPhone version of this game this quest is called "Find Five King Firebird Feathers."
This is a fairly simple quest. You should find enough firebirds around the River of Lava and Lava Lake areas. You also get one from Auntie Rilla in the Fallen Cemetery if you complete her quest. Failing that, try the Caves of Fire. Every firebird drops one feather when killed. They cast spells from a distance so the Paralyze spell can help you get close enough to kill them. Buff up your magic resistance before closing with them and you will sustain less damage.
Once you have five feathers, return to the tailor and get your reward (a nifty belt).
Strategy[]
The best decision is not to take this quest before you have feathers as timer does not start and you can make other way. If time runs out you have 750 EXP penalty. In addition you need also to visit at least at 3 way plus there is easy to divert any other line, you do not need go bridge.
Birds are smarter than evil eyes and dragons so they will not shoot if you stay to another one or friendly unit.
SPOILER[]
The Lavabird feather that you get from the Caves of Fire can be sold to the tailor for a large amount of cash.