Wild bird nest box size guide

Wild Bird	Description	Nestbox	Hole Size
Blue Tit	A bird box with a smaller hole is ideal for blue tits.	Woodcrete nest box	25mm
Great Tit	Similar to blue tits, but with a slightly larger hole in the nestbox.	Woodcrete nest box	32mm
House Martin	House martins are famed for living under the eaves of houses, so ideally you would want a nest cup.		Articial nestbox under the eave
House Sparrow	House sparrows typically use nestboxes with 32mm holes, but since they are a communal species can also use a colony nestbox.	Tom Chambers Snuggler Nest Box	32mm
Nuthatch	Nuthatches use a nestbox with a smaller hole.		28mm
Robin	Robins typically require an open-fronted nestbox that should be hidden behind vegetation.	Johnston & Jeff Robin Nest Box, Teapot nester	Open-fronted nestbox
Starling	As starlings are slightly larger birds, the nestbox hole would ideally be approximately 45mm.		45mm