Trumpeter swan Edward Preble wrote of the decline in the hunt with the number sold annually dropping from 1,312 in 1854 to 122 in 1877. Sir John Richardson wrote in 1831 that the trumpeter "is the most common Swan in the interior of the fur-counties... It is to the trumpeter that the bulk of the Swan-skins imported by the Hudson's Bay Company belong." By the early twentieth century breeding trumpeter swans were nearly extirpated in the United States except for a remnant population of fewer than 70 wild trumpeters in remote hot springs in or near Yellowstone National Park. Surprising news came
Bird vocalization and prevent an energetically costly fight . In birds with song repertoires, individuals may share the same song type and use these song types for more complex communication. Some birds will respond to a shared song type with a song-type match (i.e. with the same song type). This may be an aggressive signal, however results are mixed. Birds may also interact using repertoire-matches, wherein a bird responds with a song type that is in its rival's repertoire but is not the song that it is currently singing. This may be a less aggressive act than song-type matching. Communication through bird