NAM Verbeek 1966 [illegible] 10 June A Red Back was feeding along the edge of a bare patch when a Peetral landed within a meter of him. The Red back flew up and chased the Peetral away and this chase continued in the air for some 60-100 m., after which the Red back returned to feed in the general area from where the chase began. In the afternoon I saw a Red Back chase a Peetral at Elson Lagoon. 11 June. Observed the copulatory behavior of Red backs to day. The female stood on the edge of a snow patch when the male approached her by flying to her from some distance. He stood diagonally behind her and kept his wings outstretched horizontally. This tail was kept horizontally, not cocked thus. This lasted about 8 seconds after which he approached her with his wings held vertically above him. Still diagonally behind her on the right side and with his wings up he made a small step forward and then backward, rocking back and forth in this manner for ±5 seconds. He then stretched his left leg and touched her back. When she seemed responsive to this he mounted beating his wings all the time in a 45° angle. He remained in this position, calling excitedly for a full minute. After this period the female responded by tipping her body forward and the male made an attempt to make cloacal contact, in which he failed I think. The female then walked from under out of hair and ruffled her feathers.