Morepork they conceded the two were easily distinguishable in appearance, so maintained the three as subspecies; the Tasmanian boobook only diverged by 2.7% from the other two, while the powerful and rufous owls diverged by 4.4% from each other. Leading from this, the southern boobook was split from the Tasmanian boobook and morepork in volume 5 of the "", however several authors, including Les Christidis and Walter Boles, contested that the data had been misinterpreted from the Norman study, which had not sampled any Australian mainland boobooks at all. They treated the three taxa (southern, Tasmanian boobooks, and moreporks) as a
1977 Australasian Individual Speedway Championship England. Ivan Mauger would go on to win his record equalling 5th World Championship later in the year at the Ullevi stadium in Göteborg, Sweden. 1977 Australasian Individual Speedway Championship The 1977 Australasian Individual Speedway Championship was the second annual Australasian Final for Motorcycle speedway riders from Australia and New Zealand as part of the qualification for the 1977 Speedway World Championship. The Final took place at the Sydney Showground. Four time World Champion Ivan Mauger was the winner after defeating Phil Crump and defending Australasian Champion John Boulger in a runoff after all three riders finished on 14 points.