Tawny owls depend entirely on existing tree cavities for nesting, as they cannot excavate their own holes. Loss of veteran trees from modern forestry and urban development reduces available nest sites, limiting population recovery.
Tawny owl pairs that cannot find nest cavities have no alternative nesting strategy and fail to breed. The loss of veteran trees in both urban and rural landscapes eliminates nest sites that may have been used by successive owl pairs for decades or centuries. Young owls that disperse from natal territories face difficulty finding suitable territories with adequate nesting opportunities, leading to increased mortality in their first year.