2015-02-25 : The creature you put onto the battlefield will be returned to your hand only if it’s still on the battlefield as the delayed triggered ability resolves during the next end step. If it leaves the battlefield before then, it will remain wherever it is.

2015-02-25 : The delayed triggered ability that returns the creature to your hand will trigger even if Swift Warkite leaves the battlefield before the next end step.

2015-02-25 : You can’t put creatures onto the battlefield face down this way.