By the 1930 there were two separate populations isolated from each other.[6] In 1960, Lee Talbot reported that Arabian oryx appeared to be extinct in its former range along the southern edge of Ar-Rub' al-Khali. He believed that any oryx still existing would be exterminated within the next few years and recommended that a captive breeding program be started to save the species.[7] Michael Crouch, then Assistant Adviser in the Eastern Aden Protectorate, drew attention to the fact that each spring, small groups of oryx still emerged onto the gravel plains in the northeast corner of the Protectorate, where he thought a capture attempt would be possible.