Trumpeter swan Hoopers; are the least." Early efforts to reintroduce this bird into other parts of its original range, and to introduce it elsewhere, have had modest success, as suitable habitats have dwindled and the released birds do not undertake migrations. More recently, the population in all three major population regions have shown sustained growth over the past thirty-year period. Data from the US Fish and Wildlife Service show 400% growth in that period, with signs of increasing growth rates over time. One impediment to the growth of the trumpeter swan population around the Great Lakes is the presence of a growing
Trumpeter (bird) bronze iridescence, particularly on the wing coverts and the lower neck. In the best-known taxa the secondary and tertial flight feathers are white, grey, or greenish to black, and hairlike, falling over the lower back, which is the same colour. These colours give the three generally accepted species their names. Traditionally only three species of trumpeters have been recognised. In 2008 a review of the morphology of the dark-winged trumpeter resulted in the recommendation of splitting it into three species. In 2010 a review of the phylogeny and biogeography of all members of the family resulted in a total of