EPOW - Ecology Picture of the Week

Red-billed Queleas:  Winged Vortex

Red-billed Quelea (Quelea quelea aethiopica), Family Ploceidae
Sinya Wildlife Management Area, Tanzania

Explanation:  This week we are in northern Tanzania, in Sinya Wildlife Management Area, along the border with Kenya ... and viewing a maelstrom of birds at a waterhole.

These are Red-billed Queleas, the most numerous bird on Earth, perhaps numbering on the order of 1.5 billion strong world-wide.  

View this week's video to see just a tiny flock of this species, swirling like a living tornado.

Red-billed Queleas belong to the family of weavers and Old World sparrows, and are found widely in east Africa.  They can form flocks so immense that they can strip entire croplands of cereal grain, and thus are a major agricultural pest species.  Flocks can be so immense that they seem like living smoke clouds, and act like avian locust hoards in near-Biblical proportions.  

Why do they form such huge flocks?  Some theories suggest that flocking can confuse and overwhelm predators and thwart attacks; that massive flocks can easily absorb predation and remain resilient; that large flocks can serve as early warning signals of an approaching predator; and that living in large flocks greatly reduces the odds of being singled out by a predator.

Diminutive and attractive, Red-billed Queleas nontheless can
impose terrible hardships on farmers and local communities
as they deplete and ruin entire agricultural crops.

 

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Important observation:  In August 2004, I observed a small colony of Red-Billed Queleas in a grassland savanna (with grasses 0.5 - 1 m tall) embedded within tropical forest, near the small village of Mobenzeno, along the Ubangi River in western Democratic Republic of Congo.  

The species has not been reported from the central tropical region of Africa. so this is a first sighting in that region.  

Whether the colony I observed consisted of recent invaders, or had escaped previous detection, is unknown.  

This is a very significant observation, particularly if it signals a new invasion of the species where it might eventually become established and spread to depredate crops.  

I urge the wildlife managers of the region to monitor for the species' presence and spread. 

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Information:
     Lararus, J.  1979.  Flock size and behaviour in captive red-billed weaverbirds (Quelea quelea): Implications for social facilitation and the functions of flocking.  Behaviour 71(1-2):127-145.