who sighted it?
The indigenous people
Choiseul pigeon
The indigenous people interviewed by this expedition largely believed that the pigeon was extinct in 1929. 
please describe to me the choiseul pigeon It is an extinct species of bird in the pigeon and dove family, Columbidae. when was it last sighted? 1904 where was this? Island of Choiseul in the Solomon Islands
wiki:9253320
Choiseul pigeon [SEP] Last sightings
The indigenous people interviewed by this expedition largely believed that the pigeon was extinct in 1929. The last reported indigenous sighting was sometime in the early 1940s near Sasamungga by the Kolombangara River, although this sighting was never confirmed. Searches of the small, cat-free islands of Rob Roy Island and Wagina off Choiseul's southeast coast and Choiseul's forested coastal swampland in the 1960s by British ornithologist Shane A. Parker did not discover any signs of the pigeon. American scientist Jared Diamond searched for the bird in 1974 without success.