Hunters Surprise - Advanced Rogue Talent

[Crexis]

http://www.d20pfsrd.com/classes/core-classes/rogue/rogue-talents/paizo-rogu e-advanced-talents/hunter-s-surprise-ex

1/day Designate single enemy that is adjacent as prey. Until end of next turn, you can add sneak damage to all attacks made against your prey, even if she not flanking or not flat footed.

My question is, when I designate the single enemy the 1 time of day, is it a free action or a standard action?

[Zarius]

Unless specified, all actions are considered Standard Actions. Though, I'm hard on that one, "designating as pray" seems a little... easy. If I were the GM, I could be convinced to lighten it to a Swift, but... without specifying, it's technically a standard.

[Gallant Armor]

Combat wrote:

Using an extraordinary ability is usually not an action because most extraordinary abilities automatically happen in a reactive fashion. Those extraordinary abilities that are actions are usually standard actions that cannot be disrupted, do not require concentration, and do not provoke attacks of opportunity.

EX are free by default.