Wildlife

Wild Bird: Crossbill Irruption Welfare

Crossbills periodically irrupt into the UK in large numbers from continental Europe when conifer cone crops fail, with welfare depending on finding adequate food resources.

Key Facts

Common crossbills breed in Scandinavia and irrupt into the UK when Norwegian spruce cone crops fail
Irruptions can bring tens of thousands of crossbills to UK conifer forests in good years
Crossbills have uniquely crossed mandibles that allow extraction of seeds from closed conifer cones
Without adequate cone crops, irrupting crossbills face starvation if they cannot locate alternative sites
Scottish crossbills are resident specialists on Scots pine that do not irrupt

Welfare Considerations

Irrupting crossbills face significant welfare challenges when they arrive in the UK - having made a potentially long flight, they must quickly locate adequate cone-bearing conifers. Birds that exhaust their fat reserves during travel face starvation risk if suitable habitat is not found. Maintaining diverse conifer plantations and protecting mature cone-bearing trees improves the welfare prospects for arriving irruptants.

What You Can Do

Report crossbill irruptions to BTO and local wildlife recorders
Submit crossbill flock size data to help track irruption extent
Maintain or advocate for diverse age-class conifer forests that provide crossbill food across years
Learn to identify crossbill species and their vocalisations
Visit conifer forests during irruption years to observe this spectacular wildlife event