Inside the crater of a volcano on Graciosa Island in the Azores archipelago in the Atlantic, an international team of researchers has discovered the bones of an unknown species of extinct songbird, a bullfinch they have named Pyrrhula crassa. The remains were found in a small cavity through which lava flowed long ago. This bird disappeared a few hundreds of years ago due to human colonization of the islands and the introduction of invasive species, as was the case with numerous bird species on other islands, such as the Canaries and Madeira.
Now, an international team of scientists has discovered the bones of this bullfinch in a cave located in a 12,000-year-old volcano in the southeast of the island. "It is the first extinct passerine bird described in the archipelago, and it won't be the last," said Josep Antoni Alcover Alcover, co-author of the study published in Zootaxa, which focused on the analysis of beak morphology in order to determine the new species.
There are few known remains of this bird, but they are sufficiently distinctive for the scientists to have succeeded in establishing that they belong to a new extinct species of bullfinch. The largest of its genus according to the size of the skull remains, it is reminiscent of a bullfinch from São Miguel, which is vulnerable to extinction because of the expansion of agriculture and the disappearance of laurel forests.
"Its short, wide beak was not just considerably bigger, but also relatively higher than that of the common bullfinch or that from São Miguel, with a very robust configuration reminiscent to an extent of the beak of a small parrot," said the researcher.
These islands were colonized during the 13th century by the Portuguese, although they could have been visited by Vikings over 1000 years ago. Just as has happened on many other islands such as the Canaries or Madeira, many bird species have disappeared throughout the last millennium due to the arrival of humans and invasive species.
Human colonization led to the destruction and burning of the island habitats in which humans settled, and they impacted the indigenous fauna. P. crassa was no exception, finding itself driven to extinction. The introduction of invasive plant species has depleted and reduced the area of the laurel forests in which this species lived by up to 3 percent. According to the scientists, although remains of P. crassa have only been identified in Graciosa so far, it could have inhabited other islands of the Azores archipelago.
Explore further: The five bird species that Darwin couldn't discover in Madeira and the Azores
Rando, J.C et al. "A new extinct species of large bullfinch (Aves: Fringillidae: Pyrrhula) from Graciosa Island (Azores, North Atlantic Ocean)" Zootaxa july 2017