かき鳴らし鳥

飛行
かき鳴らし鳥がプレイヤー１人に戦闘ダメージを与えるたび、増殖を行う。（あなたはカウンターの置かれているパーマネントやプレイヤーを望む数だけ選び、その後それらのそれぞれに、その上に置かれているうち１種類のカウンターを１個置く。）

敲击鸟

飞行
每当敲击鸟对任一牌手造成战斗伤害时，增殖。（你选择任意数量其上有指示物的永久物和／或牌手，然后在其上放置一个它已有之类别的指示物。）

Thrummingbird

Flying
Whenever Thrummingbird deals combat damage to a player, proliferate. (Choose any number of permanents and/or players, then give each another counter of each kind already there.)

Commander Masters

Phyrexia: All Will Be One

Flying
Whenever Thrummingbird deals combat damage to a player, proliferate.

New Capenna Commander

An ability that triggers "Whenever you proliferate" triggers even if you chose no permanents or players while doing so.

If a permanent ever has both +1/+1 counters and -1/-1 counters on it at the same time, they're removed in pairs as a state-based action so that the permanent has only one of those kinds of counters on it.

If a player or permanent has more than one kind of counter on it, and you choose for it to get additional counters, it must get one of each kind of counter it already has. You can't have it get just one kind of counter it already has and not the others.

Players can respond to a spell or ability whose effect includes proliferating. Once that spell or ability starts to resolve, however, and its controller chooses which permanents and players will get new counters, it's too late for anyone to respond.

To proliferate, you can choose any permanent that has a counter, including ones controlled by opponents. You can choose any player who has a counter, including opponents. You can't choose cards in any zone other than the battlefield, even if they have counters on them.

You don't have to choose every permanent or player that has a counter, only the ones you want to add another counter to. Since "any number" includes zero, you don't have to choose any permanents at all, and you don't have to choose any players at all.