|Male breeding plumage of Q. q. lathamii|
The red-billed quelea (Quelea quelea), also known as the red-billed weaver or red-billed dioch, is a small, migratory, sparrow-like bird, with a conical bill. The species is restricted to Sub-Saharan Africa and avoids forests, deserts and colder areas such as at high altitude and southern South Africa. It is assigned to the weaver family. It was named by Linaeus in 1758, who considered it a bunting, but Reichenbach assigned it in 1850 to the new genus Quelea. Three subspecies are recognised, Quelea quelea quelea occurring roughly from Senegal to Chad, aethiopica, from Sudan to Somalia and Tanzania, and lathami from Gabon to Mozambique and South-Africa. It feeds primarily on seeds of annual grasses, but also causes extensive damage to cereal crops. Therefore, it is sometimes called "Africa's feathered locust". The usual pest control measures are spraying avicides or detoning fire-bombs in the enormous colonies during the night. Extensive control measures have been largely unsuccessful to limit the quelea population. When food runs out, the species migrates to locations where in recent weeks the rains have started and grass seed is plentiful and so exploits its food source very efficiently. It is considered to be the most abundant bird on earth, with the total post-breeding population sometimes peaking at an estimated 1½ billion individuals. It feeds in huge flocks of millions of animals, with birds that run out of food at the rear flying over the entire group to fresh feeding at the front, creating an image of a "rolling cloud".
Taxonomy and naming
The red-billed quelea was one of the many bird species originally described by Linnaeus in the landmark 1758 10th edition of his Systema Naturae, where it was given the binomial name of Emberiza quelea, without giving a literature reference however. He incorrectly mentioned that it originated in India, probably because ships from the East Indies picked up birds when visiting the African coast on their return to Europe. It is likely he had seen a draft of Ornithologia, sive Synopsis methodica sistens avium divisionem in ordines, sectiones, genera, species, ipsarumque varietates, a book written by Mathurin Jacques Brisson that was to be published in 1760, and which contained a black and white drawing of the species. Linnaeus corrected the type locality to Africa in the 12th edition of his Systema Naturae of 1766 and cited Brisson. Brisson called the bird Moineau a bec rouge du Senegal "red-billed sparrow from Senegal" in French and Passer senegalensis erythrorynchos in Latin. Also in 1766, George Edwards illustrated the species in color, based on a living male in the collection of a Mrs Clayton from Surry. He called it "Brazilian sparrow", being unsure whether it came from Brazil or Angola. In 1850, Ludwig Reichenbach thought the species was not a true bunting, but rather a weaver, and created the genus name Quelea, as well as the new combination Q. quelea. The white-faced morph was also once described as a separate species, Q. russii.
Three subspecies are recognized. In the field, they are distinguished by differences in male breeding plumage.
- The nominate, Quelea quelea quelea, is native to west and central Africa, where it has been recorded from Mauritania, western and northern Senegal, Gambia, central Mali, Burkina Faso, southwestern and southern Niger, northern Nigeria, Cameroon, south-central Chad and northern Central African Republic.
- Q. quelea lathamii was erected by Andrew Smith in 1836. It ranges across central and southern Africa, where it has been recorded from southwestern Gabon, southern Congo, Angola (except the northeast and arid coastal southwest), southern Democratic Republic of Congo and the mouth of the Congo River, Zambia, Malawi and western Mozambique across to Namibia (except the coastal desert) and central, southern and eastern South Africa.
- Q. quelea aethiopica was distinguished by Carl Jakob Sundevall in 1850. It is found in eastern Africa where it occurs in southern Sudan, eastern South Sudan, Ethiopia and Eritrea south to the northeastern parts of the Democratic Republic of Congo, Uganda, Kenya, central and eastern Tanzania and northwestern and southern Somalia.
Over time, two other subspecies have been described. Q. quelea spoliator was described by Phillip Clancey in 1960 on the basis of more greyish nonbreeding plumage of populations of wetter habitats of northeastern South Africa, Swaziland and southern Mozambique. However, further analysis indicated no clear distinction in plumage between it and Q. quelea lathamii, with no evidence of genetic isolation. Hence it is not recognized as distinct. Q. quelea intermedia is regarded a synonym of the nominate.
Etymology and vernacular names
Linnaeus himself did not explain the name quelea. Modern ornithologists have suggested different explanations, such as the fact that the bird comes in very large flocks, reminiscent of the quails that fed the Israelites during the Exodus from Egypt. Another possible explanation would be that the striping of the plumage looks like that of a quail's. Alternatively, quelea could be derived from quell, meaning "suppression", a reference to the destruction of crops the bird is capable of.
"Red-billed quelea" has been designated the official name by the International Ornithological Committee (IOC). Other names in English include black-faced dioch, cardinal, common dioch, Latham's weaver-bird, pink-billed weaver, quelea finch, quelea weaver, red-billed dioch, red-billed weaver, Russ' weaver, South-African dioch, Sudan dioch and Uganda dioch.
Based on recent DNA-analysis, the red-billed quelea is the sister group of a clade that consist of both remaining species of the genus Quelea, namely the cardinal quelea Q. cardinalis and the red-headed quelea Q. erythrops. The genus belongs to the group of true weavers (subfamily Ploceinae), and is most related to the fodies (Foudia), a genus of six or seven species that occur on the islands of the western Indian Ocean. These two genera are in turn the sister clade to the Asian species of the genus Ploceus. The following tree represents current insight of the relationships between the species of Quelea, and their closest relatives.
The red-billed quelea is a small, approximately 12 cm (4.7 in) long and weighing 15–26 g (0.53–0.92 oz), sparrow-like bird with a heavy, cone-shaped bill, which is red (in females outside the breeding season and males) or orange to yellow (females during the breeding season).
Over 75% of males have a black facial 'mask', consisting of a black forehead, cheeks, lores and higher parts of the throat. Occasionally the mask is white. The mask is surrounded by varying amounts of pink, yellow, purple or (in case of a white mask sometimes) black. This coloring may end on the lower throat or extend as far as the belly, with the rest of the underparts light brown or whitish with some dark stripes. The upperparts have light and dark brown longitudinal stripes, particularly at midlength, with those on the rump paler. The tail and upper wing are dark brown. The flight feathers are edged greenish or yellow. The eye has a narrow naked red ring and a brown iris. The legs are orangey in colour. The bill is bright raspberry red. Outside the breeding season, males lack bright colours, with the head being grey-brown with dark streaks, and the chin, throat whitish and a faint light stripe above the eye. At this time, the bill becomes pink or dull red and legs have turned flesh-coloured.
The females resemble the males in non-breeding plumage, but have a yellow or orangey bill and eye-ring during the breeding season. At other times, the female bill is pink or dull red.
Newborns have white bills and are almost naked with some wisps of down on the top of the head and the shoulders. The eyes open during the forth day, at the same time as the first feathers appear. Older nestlings have a horn-coloured bill with a hint of lavender, that turns orange-purple before the post-juvenile moult. Young birds change feathers two to three months after hatching, after which they resemble non-breeding adults, but with a grey head, whitish cheeks and buff margins to flight feathers and wing coverts. At an age of about five months they moult again and their plumage starts to look like that of breeding adults, with a pinkish-purple bill.
Different subspecies are morphologically distinguished by different colour patterns of the male breeding plumage. In the typical subspecies, Q. quelea quelea, breeding males have a buff crown, nape and underparts and the black mask extends high up the forehead. In Q. quelea lathamii the mask also extends high up the forehead, but the underparts are mainly white. In Q. quelea aethiopica the mask does not extend far above the bill, and the underparts may have a pink wash. However, there is much variation between individuals, and some cannot be ascribed to a subspecies based on morphology alone. Intermediate specimens between subspecies may occur where the ranges of the subspecies overlap because of interbreeding, such as at Lake Chad.
The female pin-tailed whydah could be mistaken for the red-billed quelea in non-breeding plumage, since both are sparrow-like birds with conical red-colored bills, but the whydah has a whitish brow between a black stripe through the eye and a black stripe above.
The male sings in short bursts, starting with some chatter, followed by a warbling tweedle-toodle-tweedle.
Distribution and habitat
The distribution area of the red-billed quelea covers most of sub-Saharan Africa, excluding deep portions of rain forest in central Africa. It is also generally absent from western parts of South Africa and arid coastal regions of Namibia and Angola. It was introduced to the island of Réunion in 2000.
Red-billed queleas migrate seasonally over long distances in anticipation of the availability of their main natural food source, seeds of annual grasses. The presence of these grass seeds is the result of the start of the rains weeks earlier, and rainfall varies in a seasonal geographic pattern. The temporarily wet areas do not form a single zone that periodically moves back and forth across the entirety of Sub-Saharan Africa, but rather consist of five or six regions, within which the wet areas "move" or "jump". Red-billed quelea populations thus migrate between the temporarily wet areas within each of these five to six geographical regions. Each of the subspecies, as distinguished by different male breeding plumage, is confined to one or more of these geographical regions. In southern Africa, the total population of the subspecies Q. quelea lathamii in October converges on the Zimbabwean Highveld. In November, part of the population migrates to the North-West to northwestern Angola, while the remainder migrates to the South-East to southern Mozambique and eastern South-Africa, but no proof has been found that these migration cohorts are genetically or morphologically divergent.
The red-billed quelea is mostly found in tropical and subtropical areas with a seasonal semi-arid climate, resulting in dry thornbush grassland, such as the Sahel. It is also present in farmland, where it attacks crops, although it is suggested it prefers seeds of wild annual grasses. It needs to drink daily and can only be found within about 30 km (19 mi) distance of the nearest body of water. It is found in wet habitats, congregating at the shores of waterbodies, such as Lake Ngami, during flooding. It requires bushes, reeds or trees to nest and roost. Occasionally it can be found as high as 3,000 m (9,800 ft) above sea-level, but mostly resides below 1,500 m (4,900 ft) The red-billed quelea avoids forests, including miombo woodlands.
Ecology and behaviour
Red-billed queleas have specialised on feeding on seeds of annual grass species, which may be ripe, or still green, but have not germinated yet. Since the availability of these seeds varies with time and space, occurring in particular weeks after the local off-set of rains, queleas migrate as a strategy to ensure year-round food availability. The consumption of a lot of food with a high energy content is needed for the queleas to gain enough fat to allow migration to new feeding areas. When breeding, areas with thorny or spiny vegetation below 1,000 m (3,300 ft) elevation are selected, such as Acacia, and lowveld. While foraging for food, they may fly 50–65 km (31–40 mi) each day and return to the roosting or nesting site in the evening. Small groups of red-billed queleas often mix with different weaver birds (Ploceus) and bishops (Euplectes), and in western Africa they may join the Sudan golden sparrow and various estrildids. Red-billed quelea may also roosts together with weavers, estrildids and barn swallows. Their life expectancy is two to three years in the wild, but one captive bird lived for eighteen years.
Nest building usually commences four to nine weeks after the onset of the rains and a quantity of about 300 mm has been exceeded. Nests are usually built in stands of thorny trees such as umbrella thorn acacia (Vachellia tortilis), blackthorn (Senegalia mellifera) and Dichrostachys cinerea, but occasionally in reeds or sugar cane. Colonies can consist of millions of nests, in densities of 30,000 per hectare. Over 6000 nests in a single tree have been counted. At Malilangwe in Zimbabwe one colony was 20 km (12 mi) long and 1 km (0.62 mi) wide. In southern Africa, suitable branches are stripped of leaves, a few days in advance of the offset of nest construction. The male starts the nest by creating a ring of gras by twining strips around both branches of a hanging forked twig, and from their bridging the gaps in the circle his beak can reach, having one foot on each of the branchlets, using the same footholds and the same orientation throughout the building process. Two parallel stems of reeds or sugar cane can also be used to attach the nest from. As soon as the ring is finished the male displays, trying to attract a female, after which the nest may be completed in two days. The nest chamber is created in front of the ring. The entrance may be constructed after the egg laying started, while the male works from the outside. A finished nest looks like small oval ball of grass, with its entrance high up one side, sheltered by a shallow awning. About six to seven hundred fresh, green grass strips are used for each nest. This species may nest several times per year when conditions are fit.
In the breeding season, males are diversely colored, but these differences in plumage do not signal condition but probably serve recognition of individual birds. However, the intensity of the red on the bills is regarded an indicator for the animal's quality and social dominance. Red-billed quelea males mate with one female only within one breeding cycle. There are usually three eggs in each clutch (full range one to five) of approximately 18 mm (0.71 in) long and 13 mm (0.51 in) in diameter, light bluish or greenish in color, occasionally with some dark spots. Some clutches contain six eggs, but large clutches may be the result of other females dumping an egg in a stranger's nest. Both sexes share the incubation of the eggs during the day, but the female alone does so during the cool night, and feeds during the day when air temperatures are high enough to sustain the development of the embryo. The breeding cycle of the red-billed quelea is one of the shortest known in any bird. Incubation takes nine or ten days. After the chicks hatch, they are fed for some days with protein-rich insects. Later the nestlings mainly get seeds. The young birds fledge after about two weeks in the nest. They are sexually mature in one year.
Flocks of red-billed queleas usually feed on the ground, with birds in the rear constantly leap-frogging those in the front to exploit the next strip of fallen seeds. This behaviour creates the impression of a rolling cloud, and enables efficient exploitation of the available food. The birds also take seeds from the grass ears directly. They prefer grains of 1–2 mm in size. Red-billed queleas feed mainly on a wide range of grass seeds such as from native annual grasses like species of Echinochloa, Panicum, Setaria, Sorghum, Tetrapogon and Urochloa. One survey at Lake Chad showed that two thirds of the seeds eaten belonged to only three species: Oryza barthii, Sorghum purpureosericeum and Echinochloa colona. However, when the supply of these seeds is insufficient, seeds of cereals such as barley (Hordeum disticum), teff (Eragrostis tef), sorghum (Sorghum bicolor), manna (Setaria italica), millet (Panicum miliaceum), rice (Oryza sativa), wheat (Triticum), oats (Avena aestiva), as well as buckwheat (Phagopyrum esculentum) and sunflower (Helianthus annuus) are eaten on a large scale. They have also been observed feeding on crushed corn from cattle feedlots, but entire maize kernels are too big for them to swallow. A single bird may eat about 15 g in seeds each day. As much as half of the diet of nestlings consists of insects, such as grasshoppers, ants, beetles, bugs, caterpillars, flies and termites, as well as snails and spiders. Breeding females consume snail shell fragments and calcareous grit, presumably to enable egg shell formation. One colony in Namibia of an estimated five million adults and five million chicks, was calculated to consume roughly 13 tonnes of insects and 1000 tonnes of grass seeds during its breeding cycle. At sunrise they form flocks that co-operate to find food. After a successful search, they settle to feed. In the heat of the day, they rest in the shade, preferably near water, and preen. Birds seem to prefer drinking at least twice a day. In the evening, they once again fly off in search of food.
Predators and parasites
Natural enemies of the red-billed quelea include snakes, birds, monkeys, galagos, squirrels, mongooses, foxes, jackals, hyaenas, cats, genets, civets, warthogs, lions and leopards. Bird species preying on queleas included lanner falcons, tawny eagle and marabou stork. In Etosha, African helmeted turtles were seen to grab queleas from below, while these were drinking at a waterhole. Some predators such as snakes, take eggs and nestlings. Nile crocodiles sometimes attack drinking queleas, and an individual in Ethiopia used its tail to hit birds out of the vegetation on the bank into the water, and eat them. The diederik cuckoo is considered to be a brood parasite of queleas. Invertebrates that kill and eat youngsters include the armoured bush cricket and the scorpion Cheloctonus jonesii. Internal parasites found in queleas include Haemoproteus and Plasmodium.
Interactions with humans
The red-billed quelea is caught and eaten in many parts of Africa. Around Lake Chad, three traditional methods are used to catch red-billed queleas. Trappers belonging to the Hadjerai tribe use triangular hand-held nets, which are both selective and efficient. Between 13 June and 21 August 1994 only, 1.2 million queleas were caught around N'Djamena. Birds were taken from roosts in the trees during the moonless period each night. The feathers were plucked and the carcasses fried the following morning, dried in the sun, and transported to the city to be sold on the market. Each team of six trappers process about twenty thousand birds each night. An estimated five to ten million queleas were trapped near N'Djamena each year, representing a market value of approximately US$37.500–75.000. The Sara people use standing fishing nets with a very fine mesh and Masa and Musgum fishermen cast nets over groups of birds. The impact of hunting on the quelea population (about 200 million individuals in the Lake Chad Basin) is deemed insignificant. In the Kondoa District, Tanzania, people make traps woven from star grass (Cynodon nlemfuensis), to catch hundreds of quelea daily. The bird's guano is collected in Nigeria. The large flocks attract tourists, such as in Kruger National Park. The birds themselves eat pest insects such as migratory locusts, and the moth species Helicoverpa armigera and Spodoptera exempta.
The red-billed quelea is sometimes kept and bred in captivity by hobbyists. It needs large and high cages, with lots of space to fly because it is prone to obesity. To mimic the natural occurrence in large flocks, many birds need to be kept together. The birds are very sociable, and can be kept together with other species. This species withstands frosts, but need to be able to shelter from rain and wind. Nesting can be assisted by fixing hanging branches such a hawthorn in the cage. Adults fare well on a diet of tropical seeds enriched with grass seeds. Particularly during breeding season living insects such as mealworms, spiders, or boiled shredded egg should be provided. They need fine stone grit and calcium sources, such as shell grit and cuttlebone, as well. If provided with material like fresh grass or coconut fibre they can be bred.
The red-billed quelea is considered to be the most abundant bird on earth, with the total post-breeding population sometimes peaking at an estimated 1½ billion individuals. Some estimates of the overall population have been as large as 10 billion. The species is considered a serious agricultural pest in Sub-Saharan Africa.
The traditional methods to protect crops are mainly used in subsistence farming. When the crop is vulnerable, people go into the fields, making noise, using anything from yelling to banging tins. Small stones or bits of dry mud are aimed at the birds using catapults. One person can protect about one hectare but it is very labour-intensive because the birds are active from dawn to dusk, and crops may need protection for an entire month. Scarecrows can also help, but need to be moved every two days to avoid the birds getting used to them. On a small scale farm, these methods may be quite effective. In large scale cash crops however, it is more practical to use firecrackers, exploders, or other automated noisemaking devices, firing as often as every five minutes during day light.
At the turn of the last century, the governments of Botswana, Ethiopia, Kenya, South Africa, Sudan, Tanzania, and Zimbabwe regularly managed the quelea populations. The most common method of control was by spraying the organophosphate avicide fenthion on breeding colonies and roosts. At that time in Botswana and Zimbabwe, spraying was also executed from vehicles and manually. Kenya and South Africa regularly used fire-bombs. The attempts to, at least regionally eradicate populations in the 1950s and '60s failed however, so that at present management is directed at removing those congragations that are likely to attack vulnerable fields.
- partial and complete roosting nest
- eggs inside the nest, several predators feeding on quelea chicks, nest building
- male and female at the nest
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