Thursday 15 February
The World's Favourite Unloved Species 2018 - the Galapagos Racer
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Kingdom | Animalia |
Phylum | Chordata |
Class | Aves |
Order | Struthioniformes |
Family | Struthionidae |
Genus | Struthio (1) |
The largest and heaviest of all living birds, the ostrich is instantly recognisable, with its long, bare neck, large body and long, sturdy legs (2) (4) (5). Despite its relatively small head, it is also notable for having the largest eyes of any land animal, measuring an impressive five centimetres in diameter, and protected by long black lashes (2) (4). The adult male ostrich has black plumage, with a white tail and primary feathers, and a bright pinkish or blue neck in the breeding season. The female is smaller and is grey-brown in colour, while immature birds resemble the female, but are slightly darker. Four subspecies are recognised, differing mainly in the colour of the neck and legs of the male, and in the amount of feathering on the head (2) (4) (5) (6).
Not needed for flight, the ostrich’s feathers are unusual in that they lack the tiny hooks that hold the feather together, so leaving the barbs (the ‘branches’ of the feather) loose, and giving a very soft, smooth plumage (2) (4). The ostrich is also the only bird to have just two toes on each rather prehistoric-looking foot. The inner toe is thick and strong, adapted for running, and is armed with a formidable, ten centimetre long claw, which can be used in defence. The ostrich has quite an extensive vocal repertoire, using a variety of whistles, snorts and guttural noises to communicate, as well as other sounds such as bill-snapping. The male also produces a loud “booming” call, which sounds rather like the roar of a lion and is produced during display, or at night when a predator is near (2) (5).
The ostrich’s long, powerful legs allow it to look over the top of tall vegetation when scanning for predators, and also to cover great distances in search of food. The fastest runner of any bird, it can reach up to 70 kilometres per hour in short sprints, with strides of 3 to 5 metres in length, more than compensating for its lack of flight. It is also able to outpace most mammals in terms of stamina, capable of running at up to 50 kilometres per hour for 30 minutes or more (2) (5). The diet of the ostrich includes grasses, seeds and leaves, as well as flowers, fruit and roots. The leaves, flowers and fruits of succulent plants are important in drier areas, and some insects and small vertebrates may also be taken (2) (5) (8). Ostriches typically feed in groups, browsing close to the ground (2), although S. c. molybdophanes is said to be more solitary (4).
The breeding season and strategy of the ostrich vary with location (2). Where food is scarce, breeding pairs tend to be monogamous, but elsewhere breeding groups usually form, consisting of a territorial male together with a main or “major” hen and several secondary, “minor” hens (2) (5). At the start of the breeding season, the male scrapes out a nest, a mere depression in the ground, and then attempts to attract females using an elaborate courtship display (2) (4), which involves dropping to the ground, opening the wings and tail, shaking each wing alternately, and moving the tail up and down, while swaying the head and neck from side to side. The male will then approach the female with the wings open and the brightly coloured neck puffed out, while stamping the feet (2).
After mating, the main female lays up to 11 creamy white eggs, while the other females lay around 2 to 6 eggs each, in the same nest, and may also lay eggs in other nests (2) (4). The egg of the ostrich is the largest in the world, although relatively small in relation to the size of the bird, at around 16 centimetres in length and 1.5 kilograms in weight, with a 2 millimetre thick shell. Incubation is performed only by the male and the main female, and lasts between 42 and 46 days. Any surplus eggs which the pair cannot cover are pushed out of the nest by the female, who is somehow able to recognise and retain her own, leaving about 20 eggs in total (2) (4). The young are buff-coloured with black lines and specks, and leave the nest within the first three days. The pair may sometimes take chicks from other broods, and large crèches often form, escorted by one or more adults. The adult birds may attack potential predators when defending the young, and have even been reported to kill lions with a kick. The young ostriches fledge at 4 to 5 months and are fully grown by about 18 months, reaching sexual maturity after 3 to 4 years and potentially living for up to 30 to 40 years (2).
Although it has now been lost from much of its original range, the ostrich occurs across much of Africa, and has also been introduced to southern Australia (2) (4) (5) (7). The subspecies Struthio camelus camelus (North African ostrich), once found across the whole of North Africa, is now restricted to the western and southern Sahara and the Sahel. S. c. molybdophanes (Somali ostrich) occurs from Somalia to Kenya, where it overlaps with S. c. massaicus (Masai ostrich), which occurs from Kenya, through Tanzania, Zambia and Mozambique, and south to the Zambezi River. S. c. australis (South African ostrich) originally occurred south of the Zambezi and Kunene rivers to the southern tip of South Africa, but is now found mainly in the northwest of its former range, such as in the Kalahari and Namib deserts, with some feral populations elsewhere (2) (4).
Although still relatively abundant, and not considered globally threatened (2) (7), the ostrich has decreased in numbers and range in recent times. The feathers and eggs have long been used by humans, but a fashion for using ostrich feathers for hats in the 19th Century, together with widespread egg-collection and hunting for meat and skin in the 20th Century, almost exterminated the species from northern and southern Africa. Habitat destruction, mostly in the form of overgrazing, has also greatly reduced the species’ range, and is currently considered the main threat (2). The subspecies Struthio camelus syriacus (the Arabian or Syrian ostrich), once found across the Middle East, from the Syrian Desert to the Arabian Peninsula, is now believed extinct (2) (4) (7).
International trade in the ostrich is strictly controlled under its listing on Appendix I of the Convention on International Trade in Endangered Species (CITES) (3), and the species also occurs in a number of protected areas across its range, such as in the Serengeti National Park in Tanzania (9). Attempts have also been made to reintroduce the species to the Middle East, using chicks of S. c. camelus (the most similar subspecies to the extinct S. c. syriacus) (2) (4).
Commercial ostrich farming, for feathers, meat and skins, has long been established in South Africa, and has since spread to many other countries (2) (10) (11). Today, ostrich farming is a growing industry, and considered among the most profitable agricultural projects. Indeed, a number of European and North American beef farmers have recently switched to raising ostriches commercially because of the greater and faster financial returns (11), and ostrich meat is considered a good alternative to other kinds of meat, being high in protein but low in fat and cholesterol (10). In some areas, ostriches are also raced for sport. However, despite its increasing presence in captivity, this impressive and unmistakable bird may need further conservation action in the wild if its populations are to remain secure.
To find out more about the ostrich and its conservation see:
For more information on this and other bird species please see:
This information is awaiting authentication by a species expert, and will be updated as soon as possible. If you are able to help please contact:
arkive@wildscreen.org.uk
Image credit
© Sebastián Henríquez Gárate
Sebastián Henríquez Gárate
Chile, South America
desertmonster@gmail.com
http://www.flickr.com/desertmonster
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Thursday 15 February
The World's Favourite Unloved Species 2018 - the Galapagos Racer
Thursday 01 February
Thursday 01 February