Trumpeter swan Michigan turned this line northwards, placing a hypothetical eastern boundary up through Ontario to western Quebec and the eastern shore of James Bay. In 1984, Harry G. Lumsden posited that trumpeter swans may have been extirpated from eastern Canada by native people armed with firearms prior to the arrival of European explorers and noted archaeological remains of trumpeter swans as far east as Port au Choix, Newfoundland dating to 2,000 BCE. He cited historical observer records of what must have been breeding trumpeters, such as Father Hennepin's August report of swans on the Detroit River from Lake St. Clair to
What Bird is That? according to their usual habitat. The accompanying text included brief notes on distribution, breeding and behaviour. While initial sales were poor, history tells us that Cayley had accurately discerned a market need and successfully responded to it. During WWII sales accelerated and Cayley’s first collection, reprinted time and time again, eventually became a household name among birdwatchers and the book was recognised as an Australian classic. The original sponsorship of "What Bird is That?" proved a great investment for the Gould League, who benefited from the sale of its numerous reprints and revised editions. By 1960, it was rated the