Early Bird

Pokémon with this ability will only sleep for 50% (rounded down) of the normal length. This affects sleep from moves like Spore and Hypnosis, and also from Rest.

The implementation for this is that sleeping Pokemon have a hidden counter between 2 and 5 (which is always set to 3 for Rest). When the sleeping Pokemon attempts to do anything, the counter is first reduced by 1, and if the number becomes 0, the Pokemon wakes up and takes its normal action. If the counter is not 0, the "fast asleep" message is displayed. Early Bird causes this counter to be reduced by 2 instead of 1, meaning Pokemon sleep for 1 turn under Rest, or 0-2 turns from normal sleep.

Pokémon	Type	Tier	Abilities	HP	Atk	Def	SpA	SpD	Spe	BST
Dodrio	Normal / Flying	NU	Early Bird / Run Away	60	110	70	60	60	100	460
Doduo	Normal / Flying	LC	Early Bird / Run Away	35	85	45	35	35	75	310
Girafarig	Normal / Psychic	NU	Inner Focus / Early Bird	70	80	65	90	65	85	455
Houndoom	Dark / Fire	UU	Flash Fire / Early Bird	75	90	50	110	80	95	500
Houndour	Dark / Fire	LC	Flash Fire / Early Bird	45	60	30	80	50	65	330
Kangaskhan	Normal	UU	Early Bird / Scrappy	105	95	80	40	80	90	490
Ledian	Bug / Flying	NU	Early Bird / Swarm	55	35	50	55	110	85	390
Ledyba	Bug / Flying	LC	Early Bird / Swarm	40	20	30	40	80	55	265
Natu	Psychic / Flying	LC	Synchronize / Early Bird	40	50	45	70	45	70	320
Seedot	Grass	LC	Chlorophyll / Early Bird	40	40	50	30	30	30	220
Shiftry	Grass / Dark	NU	Chlorophyll / Early Bird	90	100	60	90	60	80	480
Xatu	Psychic / Flying	NU	Synchronize / Early Bird	65	75	70	95	70	95	470