The Eurasian Wryneck never excavates a nest hole of its own, nor can it enlarge an existing hole — it is therefore entirely dependent on finding a cavity or nest box of the right dimensions ready to move into. This makes the choice and placement of a nest box unusually crucial for this particular species.
| Dimension | Value | |---|---| | Entrance hole | 45–50 mm | | Internal floor | approx. 13×13–15×15 cm | | Box depth | 25–30 cm | | Mounting height | 2–4 m |
Hole size: since the Eurasian Wryneck cannot widen a hole that is too small, it needs a considerably larger entrance hole than tits and flycatchers — on a par with a starling box. This means the wryneck often competes with the Common Starling for exactly the same cavities, and the starling, which arrives earlier in spring, often manages to take over before the wryneck is in place in May.