Red-billed quelea far above the bill, and the underparts may have a pink wash. There is much variability within subspecies, and some birds cannot be ascribed to a subspecies based on outward appearance alone. Because of interbreeding, specimens intermediate between subspecies may occur where the ranges of the subspecies overlap, 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-coloured bills, but the whydah has a whitish brow between a black stripe through the eye and a black stripe above. Flying flocks make a distinct
Red-billed quelea during daylight hours. The governments of Botswana, Ethiopia, Kenya, South Africa, Sudan, Tanzania, and Zimbabwe have regularly made attempts to lessen quelea populations. The most common method to kill members of problematic flocks was by spraying the organophosphate avicide fenthion from the air on breeding colonies and roosts. In Botswana and Zimbabwe, spraying was also executed from ground vehicles and manually. Kenya and South Africa regularly used fire-bombs. Attempts during the 1950s and '60s to eradicate populations, at least regionally, failed. Consequently, management is at present directed at removing those congregations that are likely to attack vulnerable fields. Red-billed quelea