The Story Of A Vanishing Crow - The Flores Crow

By Benjamin Elisha Sawe on December 2 2019 in Environment

Closeup of Flores crow, Corvus florensis, sitting on a tree branch.
Closeup of Flores crow, Corvus florensis, sitting on a tree branch.

Crows refer to the blackbirds popularly known for their adaptability and intelligence. The birds are also famous for their loud and harsh “caw.” Crows have been accused of destroying crops, although their impact is significantly lower than previously thought. Crows, rooks, and ravens belong to the same genus of Corvus and the family of Corvidae. According to Nature, there are about 40 different species of crows that have been identified so far, and they vary significantly in size and weight. According to LiveScience, crows are highly intelligent birds and have fantastic problem-solving skills and exceptional communication skills. For instance, it has been found that a crow encountering a mean human can teach others how to identify the human. Studies have shown that crows hardly forget a face. The majority of crow species are solitary birds, but they occasionally forage in groups. A large group of crows is known as a murder. Some of the crow species include Corvus brachyrhynchos, Corvus corone, Corvus cryptoleucus, Corvus caurinus, Corvus corax, Corvus coronoides, and Corvus florensis among others.

The Vanishing Flores Crow

Flores crow is one of the crow species endemic to the Indonesian islands of Flores, Rina, and Nusa Tenggara. They are found mainly in the lowlands in the western part of Flores Island. The scientific name of the Flores crow is Corvus florensis, and according to IUCN, they have been comparatively uncommon and were found in undisturbed habitats. Generally, they are found in low densities, and they are mostly solitary birds. Over the years, their population has declined significantly.

Population Estimates Of The Flores Crow

The population of Flores crow is estimated to be between 667 to 1,666 birds that have been rounded off to 600 to 1700 birds. These estimates are based on assessments of records and descriptions of range size and distribution. According to IUCN, the estimates are consistent with recorded populations and densities for congeners or other closely related birds with similar characteristics such as body size. The estimates in 2004 stood at about 1,000 and 2,499 birds. The IUCN contends that the population of Flores crow is declining steadily. The decline is a result of the loss of forests as well as brood parasitism. Flores crow is listed as an endangered species on the IUCN red list of endangered species.

Where Does It Live?

Flores crow is found in the semi-evergreen forests and degraded deciduous, moist monsoon forests, particularly along the watercourses with elevations ranging from sea level to about 3,117 feet above sea level. The species prefer regions where they frequent the canopy and sub-canopy of the forests. According to the surveys carried out in 2011, they were found mostly in mature forests. They were also observed to feed within the edges of the forest and in areas adjacent to cultivated vegetation. In areas with fragmented forest patches, they were absent indicating that they might not adapt well to fragmented habitats

Threats Facing Flores Crow

The main threats facing Flores crow is the loss and fragmentation of their habitats as a result of agricultural farming practices, particularly the small scale farming. The practice has encroached upon their habitats leading to a substantial decline in the population of the species. It has also resulted in the contraction of their habitat range. Although the species has exhibited tolerance to forest degradation, and drier conditions, they rely mainly on forests. One of the two main sites where the Flores crow frequent is the lowland moist deciduous forests in Golo Bilas, which has been cleared for construction materials and firewood.

Cuckoo Parasitism

Another threat facing the species, though not so significant, is the cuckoo parasitism. Flores cow species typically become the host for Channel-billed Cuckoos (Scythrops novaehollandiae) and other species such as Asian Koels (Eudynamys scolopacea). The birds in the Cuckoo family have a unique way of parental care. In the Cuckoo family of birds, 53 are regarded as brood parasites. These brood parasites lay their eggs in nests of other birds of different species. Another 83 species of the cuckoo family take the responsibility of raising their young, and some try to lay eggs in nests of their own species. As a result of this unique parasitism, the offspring of the host (Flores crow will inevitably die), and the cuckoo chick is raised instead. There are numerous benefits for the parasite birds (Cuckoo bird), which include enhanced fecundity because resources could be allocated towards producing more eggs as opposed to defending the nest, feeding the young, and incubating the eggs. Such responsibilities are transferred to the host bird (Flores crow). The cost of parasitism on the host birds are numerous ranging from diminished growth rate of nestling as a result of the competition from the parasitic chicks, to total loss of breeding by abandoning the parasitized broods, the eviction of all the eggs of the host by the early hatching parasite chicks, or the killing of host chicks by parasites chicks. According to Nature, there is a natural reciprocal relationship between the host and parasite, which is a natural selection to ensure the survival of both species. In some cases, the host can discriminate and reject the eggs or hatchlings of the parasite bird using acoustic, visual, or sensory cues. On the other hand, the parasite brood lays eggs that mimic the eggs of the host and therefore confusing the host to accept them. Such eggs have a harder shell to counter rejection through puncturing, and they have a shorter incubation period compared to the eggs of the host. Such is the evolutionary trajectories that have enabled the interdependence of brood parasitism.

Conservation Of Flores Crows

Flores crow (Corvus florensis)is listed as endangered on the IUCN red list of endangered species according to the 2016 assessment report. It has been listed as endangered since the year 2000. Between 1994 and 1996, it was listed as vulnerable, while in 1998, it was listed as threatened species. This trend indicates that the population of the species has been declining over the years. The trend could eventually lead to the vanishing of the species in the future unless the trend is reversed. Efforts have been made and the species is part of the Wae Wuul Nature Reserve and Wolo Tadho Strict nature reserve. It has also been proposed to establish conservation areas in the eastern and central parts of Flores Island. Of particular interest is the northern Ende that has extensive deciduous moist monsoon forests. It has also been proposed to expand the Wolo Tadho to support a newly established protected area in the western part of Flores Island. The areas to be included in the protected area include Tanjung Kerita Mese, Nanga Rawa, and Golo Bilas. The newly established protected areas are anticipated to be used in research to establish Flores crow’s current distribution and their population size. It will also serve as an ecological research area to assess the impact of Cuckoo parasitism.

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