Liberian greenbul, the rarest songbird not a separate species, study suggests

Liberian Greenbul, the world’s rarest songbird, was last sighted in 1984 in Cavalla Forest in Liberia. Since that time, researchers have tried hard to find this elusive bird in the wilds of this African country, but all their efforts have failed so far. Now, new research carried out by researchers from the University of Aberdeen suggests that Liberian Greenbul (Phyllastrephus leucolepis) was not spotted in the past 32 years probably because this bird never existed as a separate species, and the specimen found in 1984 was just a variant of commonly seen Icterine Greenbul.

The Liberian Greenbul is a poorly known bird species

The Liberian Greenbul is one of the most poorly known bird species in the world. There were only nine reported sightings of this bird between 1981 and 1984 in south-eastern Liberia. Later, this bird was listed as a Critically Endangered species.

In 2010 and 2013, researchers made targeted attempts to search for the bird in two specific sites in Liberia but could not find any signs of the bird. The 2013 search expedition was financed by the African Bird Club and RSPB.

According to researchers, the specimen of the elusive bird that was found in 1984 had white marks on its feathers. Such marks are not found in Icterine Greenbul’s feathers.

DNA analysis of different species of greenbul birds

In the new study, researchers carried out DNA analysis of the different species of greenbul birds. These DNA studies were performed independently by two teams of scientists in Dresden and Aberdeen to ensure that there were no errors in the final results.

The analysis revealed that there were no big genetic differences between Liberian and Icterine Greenbuls.

However, significant genetic differences were observed among other species of greenbuls. These results suggest that the Liberian and Icterine Greenbuls are most likely the same bird. The Liberian Greenbul specimen that was found in 1984 was probably an odd plumage variant of the Icterine Greenbul. This variant could have developed due to a nutritional deficiency in the bird while its feathers were still growing.

Enough evidence to suggest the possibility

Professor Martin Collinson, a researcher at the Institute of Medical Sciences at the University of Aberdeen, says they can’t say definitely that Liberian and the Icterine Greenbul are same birds, but they have provided enough evidence to suggest the possibility.

The detailed findings of the study were published in the Journal of Ornithology.