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
Dark-winged trumpeter species: "P. viridis" between the Madeira and Tapajós rivers, "P. dextralis" between the Tapajós and Tocantins rivers, and "P. obscura" east of the Tocantins. The taxon "dextralis" can potentially be split further, with "interjecta" between Tocantins and Xingu, and "true" "dextralis" for the population between the Tapajós and Xingu. Dark-winged trumpeter The dark-winged trumpeter ("Psophia viridis") is a species of bird in the family Psophiidae. It is found in the Amazon rainforest of Brazil, but only south of the Amazon River and east of the Madeira River. The eastern range of dark-winged trumpeter extends into the lower adjacent Tocantins River