Cameroon indigobird  The Cameroon indigobird ("Vidua camerunensis") is a species of bird in the family Viduidae. It is considered by some authors to be a subspecies of the variable indigobird ("Vidua funerea"). They range from Sierra Leone to east Cameroon, north east Zaire and South Sudan. There are less than 10,000 Vidua camerunensis in total, which range over 20,000 km2 in the savannah and grasslands of South Africa. The birds have a distinct blue color with underlying brown feathers and a small white beak to crack nuts and seeds. There are many indigobird species in the world, and they are mainly known for their song mimicry. The different species of indigobirds are not morphologically different, but they do differ in the songs they choose to mimic. Cameroon indigobirds are known for song determination and mimicking the songs of other bird species. The males pick which songs to mimic; however, when one male chooses a song from a host bird, the other males mimic other songs from a different host species. This is an effective way to differentiate males when mimicking the songs. There are several distinct host species that the indigobirds mimic from; the most common are the black-bellied firefinch ("Lagonosticta rara") and African firefinch ("L. rubricata"). The variation in how indigobirds mimic different songs is based on the host species. Researchers have thought that because different indigobird species sing different songs, they must be reproductively isolated. However, when a paternity test was done between the differentspecies, it was found that the birds were not reproductively isolated. They concluded that indigobirds switch songs among several different hosts, but that this switching does not mean that the species are biologically different. In fact, they are very much related to one another in which they are not isolated from other species. Reproductive isolation cannot be determined just by the shifts of song mimicry from different hosts. The indigobirds also use song mimicry for sexual and natural selection. Male indigobirds are most territorial and aggressive when they hear their own song or the host song that they mimic. These birds know and recognize which song is the one they mimic, compared to what other species mimic. For natural selection, it is in the bird's favor to mimic another song compared to other species.