8 species of birds have possibly gone extinct over past few decades

Top photo: A Spix’s Macaw. Image © Al Wabra Wildlife Preservation.

Author: Shreya Dasgupta 

Eight species of birds may have completely disappeared over the past couple of decades, a new study has found. Among these is the Spix’s macaw (Cyanopsitta spixii), a bird that inspired the character of Blu in the 2011 animated film Rio. Found only in Brazil, the bird has not seen in the wild since 2000.

Like the Spix’s macaw, several other bird species are believed to have become extinct in recent years. To pinpoint the ones that may already be gone, researchers from BirdLife International, a global partnership of conservation organizations focusing on bird conservation, looked at 51 species of birds with a “reasonable possibility of being extinct.” These are species that have either not been seen in the wild for more than 10 years despite exhaustive surveys, or species that have been seen within the last 10 years, but whose tiny population has suffered well-documented decline.

Stuart Butchart, BirdLife’s chief scientist, and his colleagues used a new statistical approach to arrive at the probability of extinction for the 51 species by combining information on the intensity of threats to the bird species, timing and reliability of records for the species, as well as timing and quality of efforts made to survey the species.

Based on their results, the researchers recommend that three species currently listed as critically endangered on the IUCN Red List be reclassified as extinct. These include the cryptic treehunter (Cichlocolaptes mazarbarnetti), last seen in the wild in 2007; the Alagoas foliage-gleaner (Philydor novaesi), not seen in the wild since 2011; and the poʻo-uli (Melamprosops phaeosoma), not seen since 2004. The Spix’s macaw, which has some individuals surviving in captivity, should be reclassified as extinct in the wild, the researchers say in the study published in Biological Conservation.

A poʻo-uli, or black-faced honeycreeper. Image © ciro_albano.

Four more bird species are dangerously close to extinction, if not already there, the team found. These species — the New Caledonian lorikeet (Charmosyna diadema), the Javan lapwing (Vanellus macropterus), the Pernambuco pygmy owl (Glaucidium mooreorum) and the glaucous macaw (Anodorhynchus glaucus) — should be treated as critically endangered (possibly extinct), the researchers say. The “possibly extinct” tag applies to a subset of critically endangered species that are, based on available evidence, likely to be extinct. However, there could be local reports of the species that need verification, or there could be a small chance that future surveys might confirm the species’ presence.

While most bird extinctions have previously occurred on islands, the rate of extinctions on continents is now increasing, the study found, driven mainly by deforestation and habitat loss, invasive species, and hunting and trapping. Five of the eight confirmed or suspected extinctions took place in South America. Of these, four occurred in Brazil, demonstrating how rampant deforestation is driving species extinctions, the researchers say.

“Ninety per cent of bird extinctions in recent centuries have been of species on islands,” Butchart said in a statement. “However, our results confirm that there is a growing wave of extinctions sweeping across the continents, driven mainly by habitat loss and degradation from unsustainable agriculture and logging.”

Citation:

Butchart, S. H., Lowe, S., Martin, R. W., Symes, A., Westrip, J. R., & Wheatley, H. (2018). Which bird species have gone extinct? A novel quantitative classification approach. Biological Conservation, 227, 9-18.