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Red-billed quelea

The red-billed quelea (Quelea quelea) is a small, sparrow-sized weaver bird in the family Ploceidae, native to sub-Saharan Africa, where it is one of the world's most abundant undomesticated avian species with an estimated population of 1.5–10 billion individuals, often forming flocks numbering in the millions.^[1] Measuring about 12 cm in length and weighing 15–26 g, it features a distinctive cone-shaped bill that is bright red in breeding males, accompanied by a black facial mask in over 75% of males (rarely white), while breeding females have yellowish bills and non-breeding birds of both sexes have red bills, with overall grey-brown plumage and streaked underparts in females and non-breeding males.^[2]^[3] Highly nomadic and migratory, the species follows seasonal rainfall patterns to exploit ephemeral grass seed resources, confining its range to semi-arid and arid savannas, grasslands, and thornveld habitats south of the Sahara, typically within 30 km of water sources, and increasingly invading agricultural areas.^[3] Primarily granivorous, the red-billed quelea feeds on seeds from wild grasses such as Sorghum species and cultivated cereals including millet, rice, sorghum, and wheat, consuming up to 15 g of seeds per day per adult bird, with nestlings supplemented by insects; this diet drives its opportunistic movements and contributes to its reputation as a significant pest, capable of devastating crops where flocks converge, with estimated losses exceeding US$50 million annually in affected regions.^[2]^[4] Ecologically, it breeds colonially in massive aggregations—sometimes exceeding 10 million pairs—constructing compact, cup-shaped nests from grass in shrubs, reeds, or thorny trees like Acacia, with socially monogamous pairs laying 1–5 pale blue eggs per clutch (typically 3) up to three times per year in response to favorable wet conditions, achieving sexual maturity at 9–12 months.^[3]^[2] Diurnally active and intensely social, these birds roost communally at night in reedbeds or trees and exhibit synchronized flocking behaviors that create dramatic aerial displays, aiding predator avoidance and foraging efficiency across their vast distribution from Senegal to South Africa.^[2] Despite its pest status prompting control efforts such as aerial spraying with avicides like fenthion and habitat manipulation in countries including Kenya and South Africa, the red-billed quelea's global population remains stable and is classified as Least Concern by the IUCN as of 2018 due to its extremely large range (25,800,000 km²) and adaptability, though ongoing agricultural expansion poses localized threats.^[5]^[1]

Taxonomy

Etymology and names

The binomial name Quelea quelea originates from the species' initial description by Carl Linnaeus in 1758 as Emberiza quelea, where the specific epithet "quelea" derives from Medieval Latin qualea, referring to a quail, possibly evoking the bird's swarming flocks akin to biblical quail plagues (Numbers 11:31).^[6] Linnaeus provided no explicit etymology, and the name's type locality was erroneously listed as India, later corrected to Senegal.^[6] In 1850, Ludwig Reichenbach established the monotypic genus Quelea for this species, adopting the epithet as the generic name, a practice that highlights its distinctiveness within the weaver family.^[6] The common English name "red-billed quelea" directly describes the prominent red bill coloration in breeding adult males, a key identifying feature that contrasts with the paler bills of females and non-breeding males.^[7] Vernacular names vary regionally, reflecting local languages and perceptions of the bird as a weaver or pest. In German, it is known as Blutschnabelweber (blood-billed weaver); in French, as Quéléa à bec rouge (red-billed quelea) or Travailleur à bec rouge (red-billed worker); and in Swahili, as kwelea domo-jekundu (red-billed quelea).^[7] Other historical English synonyms include "red-billed weaver," "red-billed dioch," and "quelea finch," with "dioch" likely derived from West African indigenous nomenclature.^[7] No major nomenclatural changes have occurred since Reichenbach's classification, though early misplacements in genera like Loxia (crossbills) were quickly rectified.^[6]

Classification and phylogeny

The red-billed quelea (Quelea quelea) belongs to the family Ploceidae, commonly known as the weaverbirds, within the order Passeriformes. It is one of three species in the genus Quelea, which is classified in the subfamily Ploceinae. Three subspecies are currently recognized, differentiated primarily by geographic distribution and subtle morphological variations: the nominate Q. q. quelea in northern sub-Saharan Africa from Mauritania and Senegal to Chad and the Central African Republic; Q. q. aethiopica in eastern regions from Sudan and Eritrea to Somalia and northern Tanzania; and Q. q. lathami in southern areas from Angola and the Democratic Republic of the Congo to Zimbabwe, Mozambique, and South Africa.^[8] Phylogenetic analyses based on multilocus molecular data, including mitochondrial (ND2, ND3, ATP6) and nuclear (Myo2, TGFb2, Fib7, MUSK) markers, have confirmed the monophyly of the genus Quelea with strong support (posterior probability = 1, bootstrap > 80). These studies, sampling all three Quelea species, place the genus in a well-supported clade (Clade D) sister to the fodies (Foudia) and certain Asian Ploceus species within Ploceinae, highlighting its close evolutionary ties to other African and Indian Ocean weavers. The evolutionary adaptations of Quelea species, including the red-billed quelea, are closely linked to their granivorous diet and nomadic flocking behavior, which facilitate exploitation of ephemeral seed resources in arid and semi-arid savannas. Large-scale flocking has evolved as an efficient foraging strategy in unpredictable environments, allowing synchronized exploitation of patchy grass seeds while minimizing predation risk through collective vigilance. No significant taxonomic revisions or debates regarding the genus have emerged from genetic analyses since 2020.^[8]

Description

Morphology

The Red-billed quelea (Quelea quelea) is a small passerine bird measuring approximately 11–12 cm in total length and weighing 15–26 g, with males typically slightly heavier at around 19 g and females averaging 18 g. ^[9]^[10] The species exhibits a compact build with a short tail and relatively broad wings suited to its flocking lifestyle, though specific wingspan measurements are not well-documented and estimated at 18–20 cm based on body proportions. ^[11] Plumage is dull and streaked brown overall in both sexes during the non-breeding season, providing camouflage in grassy habitats, with finer barring on the underparts and a pale supercilium. ^[12] In the breeding season, males undergo a striking transformation via pre-nuptial moult, developing a variable black mask extending from the face to the throat—ranging from partial white-faced morphs to full dark masks—and often a pinkish wash on the breast, while retaining the brown back and wings. ^[11]^[12] Females and non-breeding males lack this ornamentation, appearing uniformly drab with no significant plumage dimorphism outside breeding. Juveniles resemble adult females but feature buffier, less streaked plumage, a paler gape, and softer feathering that transitions during their first post-juvenile moult. ^[11] Sexual dimorphism is pronounced in coloration during breeding, with males' black mask and brighter bare parts serving as key identifiers, while females remain monomorphic year-round. ^[12] Males are also marginally larger, with wings averaging 68 mm in length (67.6 mm in breeding males vs. 67.2 mm in breeding females) and stouter bills, reflecting subtle size differences that may relate to competitive roles. ^[11] The bill is short, thick, and conical, measuring around 12 mm in length and up to 10 mm in depth at the base, ideally adapted for husking and cracking small grass seeds with its robust structure. ^[11] Bill color shows seasonal and sex-specific variation: red in non-breeding adults of both sexes due to carotenoid pigments, with males retaining red bills in breeding season while females shift to yellow via hormonal influences like estrogen; transitional mottling may occur. ^[12] Eye-rings and legs are red in non-breeding adults of both sexes; in breeding season, males retain red while females shift to yellow. ^[12]

Vocalizations and displays

The red-billed quelea employs a range of vocalizations for social coordination, particularly in large flocks, and for breeding-related communication. The primary contact call is a sharp, repetitive "chirt chirt," which individuals use to maintain group cohesion during foraging or flight.^[3] In flight, birds produce a high-pitched "tseep" to signal position within the flock.^[3] Softer, twittering calls, often described as "zee-zee," facilitate pair interactions and are more subdued compared to flock calls.^[13] Males possess a simple song repertoire during the breeding season, delivered from perches near nest sites to advertise territories and attract females. These songs consist of short bursts beginning with preliminary chatter, followed by a warbling section of repetitive phrases, typically lasting a few seconds each.^[3] The song derives from modified contact calls and is hormonally influenced, increasing in frequency and intensity as breeding progresses.^[14] Acoustic studies indicate these vocalizations play a key role in territory defense within dense colonies, where ambient noise from thousands of birds necessitates clear, repetitive signals for effective communication.^[15] Visual displays complement vocalizations, especially in courtship and agonistic contexts. During courtship, breeding males raise and flutter their wings while perched at the nest, combining this with bill raising to showcase their plumage and facial mask to prospective mates.^[15] Wing vibration, a component homologous to precopulatory behaviors in related species, often accompanies these displays.^[14] In aggressive encounters, such as territory disputes, males spread their tails and bob their heads, escalating to physical chases if vocal threats like the "chak" call fail to deter intruders.^[3] Paired birds greet each other with quivering, half-spread wings upon returning to the nest, reinforcing bonds amid the colony's chaos.^[15] These displays are essential in the noisy breeding environment, where visual cues enhance pair recognition and defense.^[15]

Distribution and habitat

Geographic range

The red-billed quelea (Quelea quelea) is native to sub-Saharan Africa, with its distribution extending from Senegal in the west to Ethiopia and Somalia in the east, and southward to South Africa, encompassing countries such as Angola, Botswana, Cameroon, Kenya, Malawi, Namibia, Tanzania, Uganda, Zambia, and Zimbabwe. This broad range covers an extent of occurrence of approximately 25.8 million km², primarily in semi-arid and grassland regions outside dense tropical forests.^[1] Three subspecies are recognized based on geographic variation. Q. q. quelea occupies western and central areas from southern Mauritania and Senegal through Mali, Burkina Faso, Niger, Nigeria, Cameroon, Chad, and northern Central African Republic. Q. q. aethiopica is found in eastern and northeastern regions, including southern Sudan, Ethiopia, Eritrea, northeastern Democratic Republic of the Congo, Uganda, Kenya, central and eastern Tanzania, and northwestern and southern Somalia. Q. q. lathamii inhabits southern extents from southwestern Gabon and southern Congo through Angola, southern Democratic Republic of the Congo, Zambia, Malawi, western Mozambique, Namibia (excluding arid coastal areas), and central, southern, and eastern South Africa.^[3] The species supports an estimated post-breeding population of 1.5 billion individuals, rendering it the world's most abundant wild bird.^[16] Recent studies from 2024 and 2025 document range shifts driven by land use changes, including expansion into agricultural fringes; for example, increased cropland and settlements in Tanzania's Chemba District have altered local distributions, while opportunistic movements into southern Africa's cereal-growing areas, such as the Western Cape of South Africa, have been linked to irrigation and feedlot developments. Its nomadic movements further influence the effective occupancy within this range.^[17]^[18]^[19]

Habitat requirements

The red-billed quelea primarily inhabits semi-arid savannas, dry grasslands, and thornveld regions south of the Sahara, often mixed with scattered woodlands that provide roosting opportunities. These environments typically feature subtropical or tropical dry conditions, including dry savannas, shrublands, and grasslands. The species is also commonly found in human-modified landscapes such as arable lands and pasturelands, demonstrating adaptability to altered ecosystems. Key habitat requirements include access to abundant grass seeds for sustenance, proximity to water sources like rivers or stagnant pools within about 30 km, and suitable nesting sites in reedbeds, thorny shrubs, or Acacia trees. Annual rainfall between 300 and 800 mm supports breeding cycles by promoting grass seed availability, though the bird persists in drier areas with reliable water access. While tolerant of farmlands and irrigated agricultural schemes, the red-billed quelea avoids dense forests such as miombo woodlands and rainforests, as well as true deserts and high-altitude zones above 3,000 m. This overlap with agricultural areas frequently results in conflicts with human activities due to crop foraging. Studies from the 2020s highlight the impacts of habitat fragmentation driven by land use changes, including agricultural expansion and settlement growth, which reduce suitable roosting and breeding sites. For example, in Tanzania's Chemba district, forested lands declined by 17.64% and water coverage by 5.6% between 2002 and 2022, while agricultural land increased by 16.89%, contributing to localized population declines and diminished habitat suitability.

Behavior and ecology

The red-billed quelea (Quelea quelea) is highly gregarious, forming enormous flocks that can number in the millions for roosting, foraging, and migration, with roost sizes occasionally reaching tens of millions of individuals.^[20] These massive aggregations facilitate information transfer about food sources, as birds observe and follow successful foragers from communal roosts, enhancing group efficiency in locating resources.^[21] Flock formation is synchronized, with birds departing roosts in dense streams, often covering daily distances of up to 30 km to foraging sites and water sources.^[22] Within these flocks, a hierarchical social structure emerges, particularly evident in breeding colonies where males establish dominance through aggressive interactions and displays, often correlated with the intensity of red coloration on their bills as an indicator of condition and status.^[23]^[5] Allopreening, or mutual grooming between individuals, serves both affiliative and agonistic functions, occurring frequently in non-breeding flocks and helping maintain social bonds while sometimes reinforcing dominance hierarchies.^[24] Mobbing behavior is also observed, with groups collectively harassing potential threats, such as predators near colonies, to deter attacks.^[25] The species exhibits nomadic movements driven by rainfall patterns and the availability of grass seeds, with populations shifting across sub-Saharan Africa to exploit seasonal resources following the onset of rains.^[26] Ringing recoveries from the SAFRING database reveal regional fidelity, with many birds recaptured near ringing sites (e.g., within 4 km at Barberspan, South Africa), yet capable of long-distance displacements exceeding 1,000 km, including movements up to 2,545 km between southern Africa and the Democratic Republic of Congo.^[27] Daily flights typically span tens of kilometers, but nomadic patterns allow for broader seasonal migrations in response to resource pulses.^[15] Recent analyses (2023–2025) of climatic variability, including rainfall and temperature fluctuations, indicate shifts in distribution and movement intensity within key wetlands like Hadejia-Nguru in northern Nigeria, where altered precipitation patterns influence flock concentrations and regional fidelity.^[28] These responses underscore the species' adaptability to environmental changes, with nomadic strategies buffering against unpredictable seed availability amid climate variability.^[29]

Breeding biology

The red-billed quelea exhibits opportunistic breeding strongly linked to the onset of rainy seasons across its range in sub-Saharan Africa, typically initiating nest-building 4–6 weeks after sufficient precipitation (300–800 mm annually) stimulates grass seeding for food availability.^[30] This timing allows for 1–3 clutches per year, facilitated by itinerant breeding where pairs or groups relocate hundreds of kilometers to exploit successive rainfall events, as documented in marked individuals moving from southwestern Ethiopia to the Awash Valley.^[31] Breeding commences at 9–12 months of age, with pair bonds forming for the season and males using vocal and display behaviors to attract mates near colony sites.^[30] Breeding occurs in massive, synchronous colonies spanning 1–100+ hectares, often containing 10,000–100,000 nests or more, with densities reaching 1,000–1,500 nests per tree in thorny acacias, reeds, or shrubs.^[30]^[32] Males construct oval, roofed nests woven from strips of green grass, featuring a side entrance and compact structure for camouflage.^[33]^[32] Each female lays a clutch of 1–5 whitish-blue eggs, typically averaging 3, with the full reproductive cycle from egg-laying to fledgling independence spanning about 42 days.^[34]^[30] Incubation lasts 10–12 days, primarily performed by the female, who covers the eggs at night and during midday heat, while the male guards the territory and supplies food; daytime warming from solar radiation (34–37°C) supplements this in hotter regions.^[3]^[32]^[35] Both parents feed the hatchlings, initially regurgitating protein-rich insects and soft seeds to support rapid growth, transitioning to harder seeds as nestlings develop; females typically provide more frequent feeds (about 6 per day) than males (4–5 per day) in observed colonies.^[3]^[35] Chicks fledge at 12–14 days, though early departure (around 11–12 days) occurs in overheated nests, with full independence shortly after; the complete nestling period thus enables quick colony turnover to align with ephemeral resources.^[3]^[32] Chick mortality is high, often exceeding 80% in some colonies due to predation by birds of prey, weather extremes, starvation from density-dependent food shortages, and nest abandonment if one parent is lost during incubation.^[32]^[35] Overall breeding success varies, with up to 95% hatching but only 80–90% fledging rates when both parents survive, dropping sharply if the female is removed early.^[32]^[35] Across subspecies—Q. q. aethiopica in eastern Africa, Q. q. lathami in southern regions, and nominate Q. q. quelea in the west and Sahel—breeding patterns are broadly similar, though colony sizes and timing shift with local rainfall variability.^[30]^[3] Recent studies post-2020 indicate stable or increasing breeding success in some areas despite habitat fragmentation from agriculture and land-use changes, as queleas adapt by exploiting irrigated crops and shifting to denser, human-modified vegetation for nesting.^[36]^[30]

Foraging and diet

The red-billed quelea (Quelea quelea) is predominantly granivorous, with its diet consisting primarily of seeds from annual grasses such as sorghum (Sorghum spp.) and millet (Pennisetum spp.), which form the bulk of its intake outside the breeding period.^[5] Insects, including beetles, grasshoppers, and termites, supplement this granivorous base, particularly during the breeding season when protein demands increase for egg production and nestling provisioning; in one study from Ethiopia's Awash River Basin, insects comprised about 10.8% of the diet during breeding.^[37] This shift supports higher nutritional needs, as females build protein reserves in flight muscles prior to laying.^[21] Foraging typically occurs in large, dense flocks on the ground or in low vegetation, where birds employ a "roller feeding" strategy, moving collectively to quickly reduce seed density in a localized area.^[38] The species' stout, conical bill is adapted for handling small seeds (1-2 mm in diameter), enabling efficient husking by perching on grass stems or cereal heads to extract and process them, though it cannot manage larger grains like whole maize kernels exceeding 4.8 mm.^[11] Males possess slightly larger bills than females, potentially aiding in seed manipulation and contributing to subtle sexual dimorphism in foraging efficiency.^[11] This flocking behavior enhances social coordination but also amplifies the scale of resource depletion.^[38] An individual red-billed quelea consumes approximately 2-3 grams of unhusked seeds per day, a modest intake that scales dramatically in swarms to enable rapid exploitation of available resources.^[39] Seasonal variations in diet and foraging reflect environmental cues and seed availability: during the early dry season, birds target small, fallen grass seeds collected from the ground, shifting to larger seeds as supplies dwindle later in the season.^[38] In the rainy season, foraging focuses on ripening grass seeds, with migrations tracking these patches, while insects become more prominent.^[5] Nutritional ecology studies highlight preferences for ripe seeds, which offer optimal energy content (around 18.4 kJ/g for grass seeds), allowing birds to build fat reserves before lean periods and sustain high reproductive output.^[11]

Predators, parasites, and mortality

The red-billed quelea (Quelea quelea) is preyed upon by a diverse array of predators, including raptors such as the lanner falcon (Falco biarmicus) and tawny eagle (Aquila rapax), as well as snakes and various mammals that target nests and roosts.^[40]^[41] Over 80 species of avian predators have been documented exploiting quelea colonies, particularly during breeding seasons when flocks aggregate in large numbers.^[5] Humans also contribute to predation through traditional hunting practices in some regions, though this has limited impact on overall population levels. The formation of massive flocks provides a dilution effect, where the risk to any individual bird decreases as group size increases, thereby reducing per capita predation rates despite the species' abundance.^[42] Parasites of the red-billed quelea include both ectoparasites and endoparasites. Ectoparasites such as chewing lice (Phthiraptera) are commonly found on queleas, with species like Machirinius quelea and Columbicola reported in West African populations.^[43] Ticks and other external parasites have also been observed feeding on birds during roosting. Endoparasites encompass nematodes, including Ascaris species, which are prevalent in gastrointestinal tracts, alongside protozoans like Giardia.^[44] Haematozoan parasites, such as Haemoproteus and Plasmodium, show variable infection rates, often low in queleas compared to other birds. Disease outbreaks include avian pox (avipoxvirus), with seroprevalence reaching 80% in some sampled populations, leading to nodular lesions and potential mortality in affected individuals.^[45]^[5] Mortality in red-billed queleas arises from multiple natural factors, including weather extremes like high winds that can cause mass deaths by dashing birds against structures, and starvation during prolonged dry seasons when seed availability declines.^[46]^[38] Annual adult mortality is estimated at around 50%, corresponding to survival rates of approximately 50%, based on ringing recoveries during periods of natural population dynamics. Recent research in 2024 has highlighted increasing parasite loads, particularly gastrointestinal nematodes and haemosporidians, in queleas inhabiting altered habitats due to environmental changes, potentially exacerbating mortality in fragmented ecosystems. Additionally, queleas serve as key prey in African food webs, supporting predator populations across savanna regions.^[47]^[48]^[49]

Human interactions

Agricultural impacts

The red-billed quelea (Quelea quelea) is a major pest of small-grain crops such as rice, sorghum, and millet across sub-Saharan Africa, where its granivorous diet enables it to target ripening seeds during breeding seasons.^[5] Swarms of these birds, often numbering in the millions, can descend on fields and cause destruction ranging from 20% to complete crop loss in affected areas, particularly in hotspots like the Sahel region and East Africa.^[50] Annual economic losses from this damage are estimated at $50–100 million USD, threatening food security and farmer livelihoods in cereal-dependent economies.^[51] Historical outbreaks intensified in the 1950s and 1960s, with peak colony formations and crop raids reported across southern and eastern Africa, leading to widespread agricultural devastation during periods of favorable rainfall and grass seed availability.^[52] In recent years, particularly in the 2020s, impacts have escalated due to expanding farmlands and increased cereal production, which have boosted quelea populations by providing more breeding and foraging opportunities; for instance, a 2022 invasion in Tanzania affected eight regions, ravaging rice and sorghum fields with flocks estimated at 21 million birds.^[4]^[53] Similar events in Kenya in 2023 destroyed up to 40% of wheat harvests in drought-stressed areas.^[54] Despite these negative effects, red-billed queleas play a positive role in natural grasslands by consuming large quantities of weed seeds, thereby providing incidental biological control of invasive grasses and aiding ecosystem balance outside cultivated areas.^[30] This seed predation on wild species like Echinochloa and Panicum helps maintain open habitats but becomes problematic when croplands encroach on their native foraging grounds.^[11]

Management and control

The management and control of red-billed quelea populations are primarily driven by their substantial impacts on small grain crops such as sorghum, millet, and rice across sub-Saharan Africa, where swarms can cause losses equivalent to millions of dollars annually.^[55] Control strategies emphasize targeting breeding colonies and roosting sites to disrupt population growth, with a shift in recent decades toward integrated approaches that minimize environmental harm.^[56] Chemical controls have historically relied on aerial or ground spraying of organophosphate avicides, particularly fenthion (Queletox®), which was effective against large swarms but highly toxic to non-target organisms, including birds of prey and mammals, leading to secondary poisoning and ecosystem disruption.^[57] Efforts to phase out fenthion have been ongoing since the early 2020s due to its toxicity, with international bodies like the FAO and Rotterdam Convention promoting alternatives, though it remains in use in several countries as of 2025.^[58]^[59] These alternatives achieve variable mortality rates, often with delayed effects that reduce immediate swarm reduction to 50-70%, though they pose lower risks to biodiversity.^[56] Physical methods include netting at breeding colonies, which can capture thousands of birds daily—such as over 19,000 in trials at Iyoli, Tanzania—and chick harvesting using poles or hooks, yielding up to 3.78 kg of birds per person per hour.^[60] Frightening devices, including explosions and fire-bombs, have been deployed in countries like Botswana and Zimbabwe, while emerging technologies such as laser scarecrows and AI-powered drones for monitoring and repellent application were tested in the 2020s, with drones covering up to 40 hectares in 30 minutes.^[56]^[61]^[62] These methods limit damage to 0-4% in protected fields compared to 2.7-18.8% without intervention, though they are labor-intensive and less scalable for massive swarms. Biological approaches focus on promoting natural predators through initiatives like trained falcons in Botswana, Zambia, and Zimbabwe, which deter quelea without chemicals, and integrated pest management (IPM) programs led by the FAO since the 1990s, incorporating cultural practices such as early planting and resistant cultivars alongside trapping.^[58] IPM has demonstrated reductions in crop damage from 85% to 30% using repellents like mesurol in Sudan trials.^[56] In 2024-2025, environmental concerns over pesticide residues—such as fenthion's persistence up to 188 days—have accelerated the adoption of eco-friendly technologies, with efficacy studies in Tanzania reporting 70-90% swarm reductions through combined drone surveillance and nest destruction, saving up to 500,000 tonnes of crops. For example, in Tanzania from December 2024 to March 2025, aerial operations destroyed over 50 million birds, saving approximately 500,000 tonnes of crops using avicides like Bathion 60% ULV and Quelea Tox.^[63]^[64] Challenges persist, including high costs and adaptation by quelea, necessitating ongoing monitoring and international collaboration.^[22]

Cultural and ecological roles

In various African communities, particularly in Tanzania's Chemba and Kondoa districts, the red-billed quelea serves as a vital food source, with local people harvesting adults and chicks using nets and traps to provide affordable protein during seasonal scarcities. These birds are consumed roasted or fresh, often sold at markets or bus stops for low prices such as TZS 100–300 (approximately USD 0.06–0.18) per portion, and are valued for their nutritional benefits, including high energy content that supports livelihoods and even perceived enhancements to physical vitality. Harvesting yields significant income, with households earning up to USD 18 weekly from live birds or USD 15 daily from roasted ones, fostering positive cultural attitudes toward the species despite its pest reputation.^[65]^[66] The red-billed quelea also holds minor roles in aviculture, where it is occasionally kept and bred in captivity by enthusiasts in large aviaries to mimic its flocking behavior, though such practices remain limited due to the bird's nomadic nature. Ecologically, it contributes to grassland regeneration through seed dispersal, as undigested grass seeds pass through its digestive system and are deposited across landscapes, promoting plant diversity in semi-arid habitats. As a primary prey item, it supports a wide array of predators, including over a dozen raptor species such as the lanner falcon (Falco biarmicus), tawny eagle (Aquila rapax), and pallid harrier (Circus macrourus), along with owls and storks, thereby bolstering food webs in sub-Saharan ecosystems. Its massive, responsive populations further serve as an indicator of environmental health, reflecting rainfall patterns and grassland productivity.^[5]^[67]^[5]^[68]^[54] The species' conservation status is classified as Least Concern by the IUCN, with a stable global population estimated in the billions across its vast 25.8 million km² range, showing no evidence of significant declines. However, recent 2025 studies highlight the need for ongoing monitoring of climate impacts, such as shifting rainfall and temperature variability altering breeding distributions in regions like northern Nigeria's Hadejia-Nguru Wetlands and Tanzania's Chemba District, potentially affecting long-term habitat suitability.^[1]^[28]^[17]

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[19]
Bird atlas in action: using citizen science data to generate ... - Frontiers
Jan 18, 2024 · Range expansion of the red-billed quelea, Quelea quelea, into the Western Cape, South Africa: Research in action. South Afr. J. Sci. 102 (1) ...
[20]
Near‐Term Forecasting of Terrestrial Mobile Species Distributions ...
Nov 15, 2024 · For this, we generate near-term distribution forecasts for the red-billed quelea (hereafter referred to as quelea) up to 7 months ahead, which ...
[21]
Communal Roosting
Quelea roosts may number tens of millions of individuals; poisons, explosives, and even flame-throwers have been used in attempts to control local outbreaks.
[22]
https://kilimo.go.ke/wp-content/uploads/2025/03/Quelea-quelea.pdf
[23]
Aggression and dominance in the weaver bird, Quelea quelea
In the present series of experiments, a number of behavioural correlates of aggression and dominance are examined in male and bisexual groups.Missing: structure | Show results with:structure
[24]
Allopreening as Agonistic Behaviour - jstor
of this type in the young of Quelea quelea when clumped together, but it ... In Fulica allopreening was recorded in winter flocks where indiscriminate ...
[25]
https://brill.com/downloadpdf/journals/beh/16/1-2/article-p1_1.pdf
[26]
Forecasting suitable breeding conditions for the red‐billed quelea ...
Mar 15, 2007 · Red-billed queleas Quelea quelea are major pests of small-grain crops throughout sub-Saharan Africa. When conditions permit, birds breed in ...
[27]
[PDF] 14 Red-billed Quelea Movements in Southern Africa shown by ...
One long distance movement of 778 km, within 6 months of ringing. • May (Figure 2e). All the recoveries in May occurred more than 6 months after ringing,.Missing: flights | Show results with:flights
[28]
(PDF) Influence of climatic variability on the distribution of Red-billed ...
Jul 19, 2025 · This paper reviews the migration and distribution of quelea based on rainfall and temperature pattern.
[29]
The migration patterns of Quelea quelea in Africa - ResearchGate
Aug 9, 2025 · Red-billed Queleas migrate, at the beginning of the wet season, away from their dry-season concentration areas and towards areas where rain started several ...
[30]
[PDF] The Quelea Birds Biology, Behavior, and Impact on Agriculture and ...
Apr 17, 2025 · As the dry season advances, food becomes scarce and flocks tend to increase in size. • A feeding flock flies in spiral and wave formations over ...
[31]
Evidence of itinerant breeding of the Red-billed Quelea Quelea ...
This paper provides evidence for itinerant breeding by Red-billed Quelea Que/ea quelea in the Ethiopian. Rift Valley. Queleas were mass-marked with aerially ...
[32]
The breeding biology of the Black-faced Dioch Quelea quelea in ...
Within any individual colony the majority of breeding is highly synchronous, with up to 90% of eggs laid and hatched within a few days of each other (Crook ...Missing: hierarchy | Show results with:hierarchy
[33]
[PDF] NESTING SUCCESS OF Quelea quelea WITH ONE PARENT ...
New information on Quelea behavior presented herein indicates that proper timing of avicidal spraying is very important and can increase the efficiency of ...Missing: mobbing | Show results with:mobbing
[34]
Land use changes and the distribution of the red-billed Quelea ...
This study offers valuable insights into the evolving land use patterns and their implications for the distribution and habitat of the quelea bird. Limitations ...Missing: range shifts 2024
[35]
https://digitalcommons.unl.edu/cgi/viewcontent.cgi?article=1022&context=vpc6
[36]
Feeding ecology of the Black-faced Dioch Quelea quelea in Nigeria
Aug 9, 2025 · Queleas are known to occur locally in the millions (Crook & Ward 1968) and have evolved efficient foraging techniques in large groups, ...
[37]
Granivorous Birds in the Sahel: Is Seed Supply Limiting ... - BioOne
Jul 5, 2023 · Queleas are known to occur locally in the millions (Crook & Ward 1968) and have evolved efficient foraging techniques in large groups, ...
[38]
Exemple de prédation naturelle sur une population nicheuse de ...
Aug 5, 2025 · Similarly, red-billed queleas (Quelea quelea) in grainproducing regions of Africa are commonly preyed on by a range of sedentary and migratory ...
[39]
Quelea - an overview | ScienceDirect Topics
Quelea refers to the red-billed quelea (Quelea quelea), which is the most significant avian pest affecting small grain crops in semi-arid regions of Africa. AI ...<|separator|>
[40]
Birds of a feather flock together: Insights into starling murmuration ...
Jun 19, 2017 · The presence of predators including harrier Circus, peregrine Falco peregrinus, and sparrowhawk Accipiter nisus was positively correlated with ...<|separator|>
[41]
[PDF] The Chewing Lice (Phthiraptera) of Red-Billed Quelea (Quelea ...
It occurs at very high populations, up to 1500 million birds in sub-. Saharan Africa (Elliott 1989; Craig 2004). There are two valid species of chewing lice ...
[42]
[PDF] BERKELEY PUBLICATION
Dec 31, 2022 · The prevalence of gastrointestinal parasites of Red-billed quelea (Q. quelea) in Gyawana ecosystem are in this order Ascaris species> Girdia ...
[43]
Seroprevalence of avian pox virus antibodies of some wild and...
All the 10 (100 %) sera obtained from Senegal parrots were positive, while only 8 (80 %) were positive out of the 10 sera obtained from Red-billed quelea (Fig.
[44]
[PDF] Powerful wind kills hundreds of birds - Semantic Scholar
Dec 18, 2023 · A powerful wind, estimated at Force 10, flung birds from trees, smashing them against a farmhouse, killing hundreds, with Red-billed Queleas ...Missing: starvation | Show results with:starvation
[45]
(PDF) Traditional capture of Red-billed Quelea ... - ResearchGate
Aug 6, 2025 · ... of about 200 million quelea birds in the Chad basin, which, in any case, has a natural annual mortality of about 50% ( Mullié 2000 ).Missing: rate | Show results with:rate
[46]
Diversity and Host Specificity of Avian Haemosporidians in an ... - NIH
Oct 9, 2024 · Whereas the lowest infection prevalence for any parasite was in the Red-billed Quelea (Quelea quelea) and Southern yellow-billed Hornbill ...
[47]
[PDF] Exploring Endoparasites and Physiological Stress: Insights from a ...
Feb 26, 2024 · Parasite loads, which are partially associated with environmental changes, can also trigger a ... Quelea quelea, Sylvia borin,. Sylvietta virens, ...<|control11|><|separator|>
[48]
Occasional Occurrences and Distributions of Red Billed Quelea ...
Oct 2, 2024 · The damage level caused by birds was varied from 0% to 100%. On average, it was determined that approximately 32.37% of the cultivated crops ...Missing: 2020s sub- Saharan
[49]
[PDF] About Us - Innovate UK Business Connect
Apr 25, 2023 · Described by the FAO as the most important granivorous bird pests in. Africa, quelea population is recorded to have increased from 10 to 100.
[50]
[PDF] CROP PROTECTION PROGRAMME - GOV.UK
Thus, Thiollay (1989) has recorded 80 species of predatory birds at ... Quelea quelea Africa‟s bird pest. Oxford University. Press, Oxford. 402 pp ...
[51]
Quelea - Africa's most hated bird - The New Humanitarian
Aug 19, 2009 · The birds are long-distance migrants with a range covering well over 10 million sq km of Africa's semi-arid, bush, grassland and savannah ...Missing: km2 | Show results with:km2
[52]
FAO in emergency response to the outbreak of Quelea quelea birds ...
Jul 18, 2022 · An estimated 21 million red-billed (Quelea quelea) birds are currently ravaging rice, sorghum, millet and wheat fields in eight regions in the southern ...
[53]
Kenya declares war on millions of birds after they raid crops
Jan 17, 2023 · In 2021, the FAO estimated crop losses attributable to the birds amounted to $50m (£40m) annually. A red-billed quelea in a rice field. The ...Missing: percentage Sahel
[54]
Red-Billed Quelea - an overview | ScienceDirect Topics
The red-billed quelea (Quelea quelea Linnaeus) is the most important avian pest of small grain crops in Africa, causing damage up to the equivalent of US ...Missing: etymology name
[55]
[PDF] A review of alternatives to fenthion for quelea bird control
Apr 4, 2017 · Fenthion, an organophosphate, is the main avicide used for controlling the pest but it is highly toxic to non-target organisms.
[56]
A review of the impacts of control operations against the red-billed ...
Aug 7, 2025 · A review of known effects of fenthion and other control measures used against Q. quelea on non-target organisms, provides a basis for comparisons with any ...
[57]
[PDF] FAO and RC Secretariat's Initiatives for Effective Quelea Control
Apr 17, 2025 · the control of red-billed workers. Workshop Objectives: Examine the report on alternatives to fenthion for the control of red-billed workers.
[58]
[PDF] NON-CHEMICAL CONTROL OF THE RED-BILLED QUELEA
The natural habitat of quelea is semi-arid Acacia country where the species relies on wild grass seeds (Setaria spp., Echinochloa spp., Sorghum spp ...
[59]
The Quelea Quandary: Zimbabwe's Persisting Agricultural Nightmare
For decades, these small, voracious birds have descended upon the country's farmlands in swarming masses, devouring crops with alarming speed and efficiency.
[60]
(PDF) Laser Scarecrows: An Innovative Technology to Control Crop ...
Jul 21, 2025 · Laser bird deterrents; originally developed for scaring away birds from airports and industrial sites; are the latest high-tech solution which ...
[61]
One pest, many risks: Quelea birds and the case for safer control
Though each bird is small, together they can wipe out entire fields of sorghum, millet, rice and wheat within hours. A single bird can eat up to 10 grams of ...Missing: agricultural | Show results with:agricultural
[62]
Tanzania destroys 50m quelea birds, saves 500,000 tonnes of crops
May 3, 2025 · In December 2024, quelea control operations continued in the Mwanga and Moshi districts of the Kilimanjaro Region. Twelve 12 sites were ...Missing: drones | Show results with:drones<|control11|><|separator|>
[63]
“Wild birds are our gold”: What livelihood implications does it hold ...
Nov 20, 2023 · Prominently, Red-billed Quelea quelea, Cardinal Quelea quelea, and Red-headed Quelea quelea (all 100 %) were significantly harvested.
[64]
(PDF) Factors affecting attitudes of local people toward the red-billed ...
Aug 6, 2025 · These birds are considered as serious pest because they consume small grain cereal crops. The red-billed Queleas are caught and consumed as food ...
[65]
https://pmc.ncbi.nlm.nih.gov/articles/PMC10687040/
[66]
Distribution and Relative Density of Raptors in the Sub-Sahara ...
Jul 5, 2023 · Numbers of Red-billed Quelea Quelea quelea, for example, an important prey of Pallid Harriers in northern Cameroon (Buij 2013), have crashed ...