Rule 377.2.b
If an Activated Ability has a condition on “using” or “playing” it, that condition must be true in order to activate the ability in question. Example: Ultrasoft Poro reads “[E]: Play two 1 [M] Bird unit tokens with [Deflect]. Use this ability only while I'm at a battlefield.” In order to activate the ability, Ultrasoft Poro must be located at a battlefield.