White-fronted tern egg predation

[Dave Houston]

Can anyone answer Tim's question?

Kia ora

This posting is for those of you can identify the culprits of egg predation based on remaining shell.

Our guess is that these White Fronted tern eggs were munched by gulls.
Does anyone with greater experience support our view or have a different theory?
If it was gulls is it likely to have been the Black Billed gulls also nesting in the area or the ever present Black backed version?

Thanks in advance for any advice you may have.

Tim Shaw | Technical Support Terrestrial Fauna | Kai Mātanga Ahuwhenua | Department of Conservation Te Papa Atawhai | West Coast Tai Poutini Conservancy
Tel: (03) 756 9142 | VPN: 5242| Fax: (03) 756 9195 Mail: Private Bag 701, HOKITIKA 7842 -Sewell Street, HOKITIKA 7810