1.   The areas, all below the low water mark, contain unusual plants and animals, including seaweeds, sponges, bryozoans, invertebrate animals and bird breeding colonies.

2.   But some bird colonies are coming back.

3.   Consequently, bones of their ancestors can be excavated from below the living bird colonies.

4.   The spill occurred at the mouth of the Tamar River, where the fuel oil is threatening certain estuary bird colonies, including breeding grounds of penguins.