// When Scion of Vitu-Ghazi enters the battlefield, if you cast it from your hand, put a 1/1 white Bird creature token with flying onto the battlefield, then populate.
Ability ability = new EntersBattlefieldTriggeredAbility(
new ConditionalOneShotEffect(new CreateTokenEffect(new BirdToken()), new CastFromHandCondition(),
"if you cast it from your hand, put a 1/1 white Bird creature token with flying onto the battlefield,"));
ability.addEffect(new PopulateEffect("then"));
this.addAbility(ability);
}