Abyssinian Ground Hornbill(Bucorvus abyssinicus)
They are also known as the Northern Ground Hornbill. They are a large, terrestrial hornbill with black body feathers and white primary feathers which are visible in flight. The adult male has a patch of bare blue skin around the eye and an inflatable patch of bare skin on the neck and throat which is red, apart from the upper throat which is blue. The bill is long and black except for a reddish patch at the base of the mandible. On top of the bill there is a short open-ended black casque. The female is similar but smaller with any bare skin being wholly dark blue.
Juvenile birds are dark sooty-brown with a smaller bill, with an incipient casque. As the juvenile matures, which usually takes 3 years, it gradually develops the plumage, bare skin colour and casque of the adults. The total length is 90-110 cm. They also have long feathers that look like eyelashes that surround its eyes. These protect the eyes from injury.
Habitat
The Abyssinian ground hornbill is found in Northern sub-Saharan Africa from southern Mauritania, Senegal and Guinea east to Eritrea, Ethiopia, north western Somalia, north western Kenya and Uganda. It is found in open habitats such as savanna, sub-desert scrub, and rocky areas, preferring short vegetation which enables its visual foraging technique. The areas inhabited by this species are usually drier areas than the preferred habitat of the Southern ground hornbill.
It will tolerate disturbed areas but does require large trees to be used as nest sites. The Abyssinian ground hornbill has escaped or been deliberately released in to Florida, USA, but there is no evidence that the population is breeding and may only persist due to continuing releases or escapes
Diet
Diet in the wild consists of a wide variety of small vertebrates and invertebrates, including tortoises, lizards, snakes, birds, spiders, beetles, and caterpillars; they also take carrion, some fruits, seeds, and groundnuts.
Breeding
The breeding season of the Abyssinian ground hornbill varies across its range: the West African populations breed in June through to August, Nigerian and Ugandan populations breed in January, and Kenyan birds breed as late as November. They prefer to nest in large trees, with baobabs and palm stumps being preferred; the nest is constructed in a cavity. They have also been recorded nesting in other types of cavities including holes in rocks and man-made cavities such as bee-hive logs or baskets. In the ground hornbills the females are partially sealed in using a mixture of mud and vegetation. In other hornbills the nesting female moult their all flight feathers at once but this is not the case in the ground hornbills. The male prepares the nest by lining the cavity with dry leaves before the female enters and lays a clutch of one or two eggs over around five days. She starts to incubate as soon as the first egg is laid so that the chick which hatches first has a head start in development over its sibling. Incubation of each egg takes between 37-41 days, during which time there is no effort to keep the cavity clean and the male is responsible for providing food to the incubating female. The weight of the newly hatched chick is around 70 g and the first-hatched grows rapidly at the expense of the second, which will normally die of starvation before it is four days old by which time its sibling can weigh as much as 350 g. When the surviving chick is 21 to 33 days old the mother leaves the nest and starts to help in food provision, then after 80 to 90 days the chick leaves the nest. Abyssinian ground hornbills invest a lot in their offspring and the fledged juveniles will remain with their parents for up to three years. They have a slow breeding rate and an average of one chick is raised to adulthood every 9 years so the adults' investment in each young bird raised is exceptionally high.
Population
According to the IUCN Red List, they are classed as Vulnerable(VU). The global population size has not been quantified, but the species is reported to be widespread and common but sparse. Accurate quantification of the rate of decline in this species is very difficult due to the lack of research in the region. In many range states the species has disappeared from areas outside of protected areas, and habitat degradation continues even within some protected areas. Hunting may also impact the species in some places, though in other areas it could be protected as a totem bird.
Threats
Habitat loss may be having a significant impact on this species, with the species now potentially being mainly restricted to protected areas. In Togo it may also have disappeared from most faunal reserves as a result of illegal habitat clearance for farming, logging etc., and may only persist in Fazao-Malfakassa National Park - although this site is now also under threat from a planned road development. Forest reserves in Benin are also being invaded by farmers, which could threaten populations of the species in this country too. Urban development may also be impacting this species, e.g. in Gambia. It is not only threatened by habitat conversion, as in certain areas hunters may kill individuals and use their stuffed heads as disguises while stalking game, although it is treated as a totem species in some areas and so may be relatively protected in such places as a result of this.
Conservation
Conservation Actions Underway
No targeted actions are known for this species, but it is becoming increasingly restricted to protected areas.
Conservation Actions Proposed
Research is urgently needed to better understand the species's biology, as well to collate a better idea of the overall population size and trends. Where possible, protect further areas of suitable habitat, as the species is becoming increasingly reliant on such areas. Raise awareness of this species to try to reduce the impact of hunting.