Fish Gotta Swim, Birds Gotta Eat

In Skettis Ruins (where the garrison daily takes place), single Darting Swift Feathers kaliri that fly in circles around coordinates 54, 10.4 occasionally perform an idle animation if not aggro-ed or killed for several minutes. The Kaliri would swoop down on a body of water and grab a fish, gaining a buff then flying up.

In order to get the achievement, you must tag and kill the Kaliri before it goes out of range or finishes the fish, becoming Energized Swift Feather. After killing the bird, the fish is dropped and becomes an lootable object. I got Spiced Barbed Trout from looting the fish, eat it to get the achievement. You also gain a buff lasting for 30mins that increases versatility by 60% (Increasing damage/healing by 60% and reducing damage taken by 30%)!

It is best to do this achievement during wee hours of the day or when skettis is not featured as the daily where you'll find less people around who are likely to aggro the birds.

EDIT: corrected wrong info. Thanks Nekyr for pointing it out!

The achievement is earned by eating food that can be looted from a clickable fish object that is dropped by [npc=84013] on death while buffed with [spell=168364] during Assault on Skettis daily. Killing buffed [npc=84013] during non-daily day does not allow the player to loot the fish; but the fish is visible and glowing.

There are 4 [npc=84013] around the small river-bed at 54:10 which is one level above of the Assault on Skettis area. The 4 [npc=84013] circulate around a small area and does a "Fish Check" every 1-2 minutes. If the bird finds a fish, the animation sequence begins for the bird to dive in the river and fly off with a buff. The two 5-m cell groups of birds do not dive for fish; so they are not needed to be tracked. The bird has to be tagged before it flies off. Bird can be tanked for a long time without allowing it to de-spawn meaning there is no need to rush kill it once tagged.

Each of the birds have a re-spawn time of 30 seconds to 90 seconds.If any of the birds turn into [npc=84231] for not being tagged and killed, there won't spawn any new [npc=84013] unless [npc=84231] is killed.

The small-medium sized rock in river-bed at 53.9:10.4 is a good place to stay still without agroo-ing any NPCs in area. As of being in middle it allows easier track of [npc=84013]. Please note that there is not only one exact spot for every [npc=84013] to dive in; however, almost all of them dive in right in front of the small-medium sized rock. Keeping a range attack skill ready is advised.

If you are lucky, a new spawned bird can go for fish hunt asap. On other hand; it can take up-to 20 minutes for one of the birds to catch fish alone.

If you are very unlucky, some friendly player might loot the fish dropped by a buffed [npc=84013] that you have tagged and killed. This would cause that player to get the achievement instead of you. The dropped fish cannot be looted by multiple players. The dropped fish does not disappear even after 45 minutes if not looted.

Alternate place is also available if camping spot is over-crowded. The area right below the small but tall waterfall, houses 3 [npc=84013] that can dive along the river. Exact or common diving spots in that area are currently not determined.

The fish isn't lootable if it isn't the daily area, so you have to do this while it is the area for the day.