Cade 1958 Phalacrocorax fulicarius 18-20 June Barrow- Commonest shorebird by far on the tundra this year - but mostly un- paired females exceeding paired birds by a factor of 10. There are consequently, many intrusions into the affairs of the pairs, and females are often seen fighting over the males. The paired female always reacts the same way when an intruder & approaches. At first the pair is quietly foraging or swimming about say from 1 to 3 feet apart. Then another female flies in and lands nearby. The paired female immediately crowds up against her- mate, places herself between him and the intruder and sideleaves to shield him away. This usually works. Only if the intruder & comes close - say within about 1 foot, does the mated female then turn and attack her. She may also pick her mate on the head if he tries to slip around her. While herding the male, the mated & often pecks out her feathers and quills. We have seen this performance enacted many times in the past two days.