The last two months we have had spectacular quelea viewing in the Lebombo Concession. We have literally seen flocks of hundreds (maybe even over a thousand birds in some of the flocks). Seeing them flying in their large flocks over the grasslands, looking like wispy trails of smoke in the sky, has been amazing.
The Red-billed quelea (Quelea quelea), also known as the red-billed weaver or red-billed dioch, is said to be the world’s most abundant wild bird species, with an estimated adult population of over 1.5 billion pairs.
These birds are part of the Ploceidae (weaver) family and only occur in Africa, south of the Sahara (although there is a small population of these birds that were introduced to Reunion Island).
They are small birds, with an average weight of between fifteen and twenty grams. During the winter months they are drably coloured, but during the breeding season the males attain a black mask often with a pink-red tinge around it and a bright red beak. The back is mottled khaki in colour and the belly is greyish-white. Some males may have a different breeding colour form, with a cream-white or pinkish-purple mask. During the summer months these birds are sexually dimorphic (males and females have different plumages), but during the winter months the males return to the eclipse plumage which is similar to the females.
In the Lebombo Concession we have quite a few knobthorn thickets (particularly in the low-lying, basalt areas) and these are the trees that are often favored for breeding sites. Breeding tends to occur in summer, after the first rains have fallen and the grass has started to grow. Queleas nest only after good rainfall has produced a flush of new plant growth, resulting in an abundance of insects and grass seeds. They breed in vast colonies that can number over a million pairs. The nests are crammed together in thorn trees, in close proximity to one another and some trees can literally have over a hundred nests in them. The males first weave half-complete ovoid nests from grasses. After the female has examined the construction and mating has occurred, both partners complete the weaving of the nest. The nest then looks like a grass ball stuck in amongst the thorn branches, with an entrance hole at the side. Within each colony breeding is remarkably synchronous, and the eggs are usually laid within a very short period of time, usually within two or three days of each other. Each nest usually contains between two to four light blue eggs, which are incubated for approximately two weeks before the chicks hatch. After the chicks hatch, they are initially fed caterpillars and protein-rich insects. Thereafter the parents then start feeding the youngsters grass seeds. The young birds fledge and become independent enough to leave their parents after approximately two weeks in the nest.
Due to the large numbers of birds in each flock, and particularly in the breeding colonies, the presence of quelea flocks often attract numerous predatory birds and other animals to the area. Since the arrival of the queleas to the concession we have noticed a huge increase in the numbers of birds of prey. In the areas that the queleas have their nesting colonies the dead trees often have at least one or two eagles perched in them. Some of the birds of prey that we have seen in the concession since the queleas arrived include tawny eagles, Wahlbergs eagles, bateleurs, yellow-billed kites, steppe eagles, lesser-spotted eagles, African hawk-eagles, lanner falcons, peregrine falcons, Eurasian hobbies, little-banded goshawks and gabar goshawks. We have also noticed a large number of marabou storks that have gathered in the northern areas of the concession, where the queleas are nesting. It is, however, possible that the storks have gathered to feed on the armoured ground crickets that have also appeared in huge numbers. Once the quelea chicks have hatched the storks will definitely go for some of the fledglings. Other creatures that will feed on the young queleas may include various species of snakes, monitor lizards, jackals, smaller cats (such as caracal and African wild cats), genets, slender mongooses, armoured ground crickets, owls, southern ground hornbills and possibly even leopards.
Red-billed queleas tend to be nomadic in nature, following the rains across Africa, searching for lush grass growth. The adults feed predominantly on grass seeds, but will also take protein-rich insects (particularly before moving from one area to another). Once the grass seeds have matured and dropped to the ground it becomes more difficult for the queleas to access them and then, once the grass seeds have all disappeared, the queleas may then turn to commercially grown crops. Queleas are known to consume millions of kilograms of cereal grains each year in Africa. For thousands of years, subsistence farmers in sub-Saharan Africa have been at the mercy of the Queleas. Massive flocks of the tiny “avian locust” still decimate fields across the continent. Although they prefer the seeds of wild grasses to those of cultivated crops, their huge numbers make them a constant threat to fields of sorghum, wheat, barley, millet and rice. The average quelea bird eats around 10 grams of grain per day – roughly half its body weight – so a flock of a million can devour as much as 10 tons of grain in a single day. A single large flock of queleas can literally destroy and entire year’s worth of crops on a single farm. Farmers therefore, justifiably, see queleas as a danger to their livelihoods and attempt to eradicate them when they are seen near the farms. In the past quelea numbers were controlled by aerial spraying with organophosphate pesticides (usually fenthion – also known as “quelea-tox”). However, it was found that the use of these pesticides had a massive detrimental effect on the ecology of the area. Raptors, which often gather to feed on the queleas and their chicks, are often killed as a result of secondary poisoning. Pesticides that enter aquatic ecosystems often kill various animal and bird species, and can have serious consequences to functioning of these ecosystems. Other methods of controlling the quelea populations and reducing damage to crops include the use of bird-scaring techniques (this is very labor-intensive as it involves using people to actively chase the birds away and to make loud noises around breeding colonies in order to discourage the birds from nesting), the use of explosives (when the birds roost at night dynamite is placed at the base of the trees and then the birds and trees are blown up) and the use of flame-throwers and fire. Since the 1950s it is estimated that between 40–100 million queleas have been killed each year.
Presently it is being looked at to catch queleas and use them as a food resource for poor, rural communities (particularly in drought-stricken areas).
Another interesting thought that is being considered is how queleas affect the habitats where they nest and feed. It is obvious that the presence of queleas in an area affects the area by consuming seeds and insects. Red-billed queleas probably also play major roles in seed distribution and nutrient re-cycling, and as food for other organisms. It is also thought that Red-billed queleas may be influential in the destruction and creation of habitats, as their nitrogen-rich droppings promote grass and Acacia growth but also raise fertility levels above those tolerated by other species of trees.
Although Queleas are considered to be problem “animals” when they are found moving through farming areas they are still protected in nature reserves. In 2010 it was estimated that there were 33 million red-billed queleas in the Kruger National Park alone.
We have, however, been very fortunate to see big flocks of queleas and the associated predatory birds that accompany them in the concession during the last two months. It has been quite spectacular!
Images of other bird species: Wahlberg’s eagle, Peregrine falcon, and Marabou storks with queleas flying past.