The Quelea, a small passerine native to sub-Saharan Africa, is widely recognized for its vast populations and highly social nature. These birds often gather in immense flocks, numbering millions, which contributes to their reputation as a significant agricultural concern.
Defining the Quelea: Characteristics and Behavior
The Red-billed Quelea ( _Quelea quelea_ ) is a sparrow-like bird, measuring around 12 cm (4.7 in) in length and weighing between 15 and 26 grams (0.53-0.92 oz). Its most distinguishing feature is its cone-shaped, bright red bill, which is well-suited for crushing seeds. Outside of the breeding season, both sexes have a generally brownish-yellow plumage with striped brown upper parts and lighter underparts.
During the breeding season, male Queleas undergo a change in appearance, developing a black or sometimes white facial “mask” that covers the forehead, cheeks, and throat. This mask is often surrounded by a wash of yellow, purplish, pinkish, or rusty hues on the head and breast. Females typically have a yellow or orange bill and a distinct orange eye ring. Their collective behavior is evident in their feeding, roosting, and breeding activities, creating the visual impression of a rolling cloud as birds at the rear fly over the front to access new feeding areas.
Habitat, Diet, and Life Cycle
Queleas are widely distributed across sub-Saharan Africa, thriving in a variety of semi-arid habitats including grasslands, savannas, and cultivated areas. Their nomadic behavior allows them to move considerable distances, sometimes over 3,000 km annually, in search of food and suitable breeding grounds. They roost in large aggregations in reeds or thorny trees near water sources.
The primary diet of the Red-billed Quelea consists of seeds from wild grasses, which they consume both from the plants and from the ground. While wild seeds are their preferred food source, they will readily turn to cultivated grains like sorghum, millet, wheat, and rice when wild seeds become scarce. During the breeding season, their diet also includes insects such as grasshopper nymphs, termites, and caterpillars, which provide protein for their developing young.
Queleas have one of the shortest breeding cycles among birds, which contributes significantly to their rapid population growth. Breeding is often triggered by environmental signals like rainfall and the emergence of green vegetation, occurring in large colonies that can span hundreds of hectares. Females typically lay around three pale blue eggs, which are incubated for about 10 to 12 days. The chicks fledge and become independent within approximately two to three weeks after hatching, with the entire breeding cycle from egg-laying to independent young taking about six weeks.
The Quelea’s Agricultural Impact
The Quelea bird is widely regarded as the most significant avian pest in Africa due to the extensive damage it inflicts on cereal crops. They form colonies that can reach up to 30 million individuals, enabling them to decimate vast agricultural fields within hours. This large-scale consumption directly impacts food security and causes substantial economic losses for farmers across sub-Saharan Africa.
A single Quelea can consume up to 10 grams of grain daily, meaning a flock of just two million birds can consume around 20 tonnes of grain in a single day. Crops vulnerable to Quelea attacks include wheat, sorghum, millet, and rice, especially during the milk-dough grain growth stage. The annual economic impact of Quelea damage is estimated to be as high as US$88.6 million across semi-arid zones. This extensive crop destruction has earned the Quelea the moniker “Africa’s feathered locust”.