The Charles Darwin Foundation is in charge of providing information on the population status of the species, in order to compare and anticipate the reduction of its population. The populations that have decreased the most are: the swallow (Progne modesta), the witch bird (Pyrocephalus nanus), and the Galápagos pigeon (Zenaida galapagoensis).
The plan proposed by the CDF is focused on 29 species of small terrestrial birds such as mockingbirds, finches, pigeons and flycatchers. Some were studied by the English Charles Darwin in the nineteenth century and were key pieces for his theory of evolution.
The vermillion robin (Pyrocephalus dubius) or also known as the witch bird is the only endemic bird in Ecuador that is considered extinct for the International Union for the Conservation of Nature. These species of birds inhabited in San Cristóbal, one of the four populated islands of Galápagos.
In the 80´s, there were the last sightings of this species, but there is still a hope of finding them again, informed by the scientist David Anchundia who has been part of the Galapagos Landbird Monitoring Plan for the Charles Darwin Foundation (CDF) since 2014.
The disappearance of the witch bird, which is endemic to the Galapagos, has quickly occurred from the populated islands. In recent years, it was determined by several investigations, that both in the islands of San Cristóbal and Floreana, there are no track of the specimen.
This bird is insectivorous, which has generated an impact on the parasitic fly Philornis downsi, given that in its larval stage, it feeds on the blood of the young of the nest, producing weaknesses and in some cases death, Anchundia mentions.
This insect affects more than 20 species of land birds in Galapagos. “Several experiments to avoid damage to the colony of the witch bird, consists of injecting at the base of the nests, a minimum amount of insecticide. This method is having a positive effect for birds, since they have a higher percentage of reproductive success, “says Anchundia.
The complications of studying these species of small birds, usually occur when nests are in high territories with inaccessible sites. The Galápagos swallow is one of the most difficult specimens to observe, and its nests are mostly found on cliffs facing the sea. “In 2018 two accessible nests could be found, but when we checked them we found that the larva of the fly also affects this species,” he adds.
Another case is the Galapagos pigeon, which has had very little sighting on the islands of San Cristóbal and Floreana, but on Santa Cruz Island, they are still seen in the upper part. It was determined that this bird is commonly found on islands not inhabited by cats. “Since it is a docile bird, which makes it easy prey for wild cats on inhabited islands.”
Several threats haunt these species. Diseases, Rats, cats, change in food sources and reduction of forests for agriculture. “The most affected birds are the insectivores in the Galapagos Islands. Due to a research in recent years, the decrease in prey (insects) was determined, “he says.
The population is counted at the beginning of the breeding season (January and February) when the first rains are sighted and the birds begin with their songs. “In these times they are when they look for a couple to nest. Therefore, it is the best time to analyze the population, since our methodology focuses on capturing each of its songs. This procedure is carried out by moving to the field, listening and recording all the birds that sing at a specific point during five minutes “.
This procedure is repeated every 200 meters, but for this, it requires a sharp ear to differentiate the songs of each of the species. After carrying out the field work, we proceed with the tabulation of the information and through a computer program, we estimate the number of birds of each species for each sector.
Casa Natura Galapagos Lodge is actively engaged in the conservation of bird species such as those found throughout the Galapagos Islands. If you want to enjoy bird watching on the islands, you can ask about our Galapagos tours in Santa Cruz, San Cristobal and Isabela Islands.
Do not hesitate to contact us at: (593) -998906400 / (593) – 44506016 or write to [email protected]. We will be happy to plan your vacation in the Galapagos Islands.