Africa’s Red-billed Quelea (with the complicated scientific name of Quelea quelea), is probably the most abundant terrestrial bird species in the world. With an estimated breeding population of 1.5 billion, these little seed-devourers can cause havoc on the continent’s crop production. The sight of a flock of a million-plus queleas descending on your crops in a smoky cloud must be terrifying to any crop farmer. Depending on rainfall, some 190 millions queleas may reside in South Africa. Some acrobatic avian maths suggest that a flock of 400,000 queleas can consume 1.6 tons of grain per day, amounting to a loss of nearly a million Rand per day. Scary stuff.
So much so, that quelea numbers are controlled in some areas with crops such as wheat, sorghum, millet, manna, sunflowers, peas, buckwheat, rice and oats. [Sensitive readers beware] the two main culling methods are explosions/fires in roosting colonies, and aerial spraying of avicide poisons. Such extreme measures obviously have a lot of accidental mortality (collateral damage), so more environmentally friendly control methods are employed in sensitive areas. Alternative methods of controlling quelea number sinclude harvesting of quelea chicks, trapping birds with nets, chasing, creating roosts in other areas, altering foraging and roosting habitats, repellent chemicals, planting resistant cultivars and varying timing of planting.
Even so, the annual mortality of queleas resulting from control actions is somewhere around 100 million birds. Nevertheless, despite these high rates the overall quelea population seems remarkably resilient, and there is little long-term effect on their populations. This is in part due to their rapid breeding cycle and their ability to undertake nomadic wanderings in search of food.
Everybody is quick to point the finger at aliens such as mynas, parakeets and pigeons, but queleas can also be seen as ‘alien invaders’ in some sense. With the intensification of agriculture (crop planting, irrigation etc.) throughout South Africa, queleas have ‘invaded’ areas where they previously didn’t occur. In recent years their range has expanded in areas such as the Karoo, Eastern Cape, KZN Midlands and Western Cape.