The most numerous wild bird on earth, estimated at 1.5 billion individuals, is the red-billed quelea (Quelea quelea) of sub-Saharan Africa. This very social weaver finch migrates and nests in flocks that number in millions.

When the flocks get going they resemble swarms of locusts.

Red-billed queleas eat mostly grain and seeds. As they feed on the ground the flock leapfrogs from back to front like a rolling cloud.

In Africa they are so well known as flocks that it’s hard to think of them as individuals. Two males are pictured above. Here’s a female.

Unfortunately their numbers and flocking behavior get them into trouble. When their natural food sources run dry they change their focus to cultivated fields. A flock of two million can eat 20 tons of grain in a day, thus …

This species is a major pest of cereal crops, and huge efforts have been expended by national and international agencies on lethal control and attempts to reduce population numbers by use of explosives, petrol bombs and aerial spraying of [organophosphate] avicides; in South Africa up to 21 million reported killed in a single month, with annual kill estimates of up to 180 million.

Control operations, however, probably do no more than replace naturally occurring mortality, and there is a significant adverse impact on other species, which are poisoned directly or die after eating dead queleas.

— Birds of the World, Red-billed quelea

A much more successful control measure than killing them, though very labor intensive, is to actively make noise in the fields and scare the birds away.

After more than 70 years of control measures that kill hundreds of millions of birds per year, the red-billed quelea population has grown.

(photos from Wikimedia Commons; click on the captions to see the originals)

p.s. A video at this link shows all aspects of the red-billed queleas lives but is grisly at the end.

On Labor Day let’s honor working birds. This year … domestic geese.

A couple of domestic geese are often kept with chickens to guard them from predators. Geese are always alert and will naturally honk and shout when they see danger. The chickens run for cover while the large and aggressive geese may attack the threat. Some geese are so aggressive that they’ve injured people. (By the way, Canada geese will attack if you approach their young.)

A farmer who used geese and guineafowl to guard his chickens says domestic geese are the best. Geese alarm only when they see a threat; the farmer knows there’s a good reason to check on the flock. Guineafowl are noisy but they alarm for almost anything.

When you see geese with chickens you can be sure those geese are at work.

p.s. When seen in Pennsylvania, geese like those pictured above are barnyard escapees. Here are some tips on their background: Chinese geese have long necks and knobs on their heads (top photo) and were domesticated from swan geese (Anser cygnoides). Domestic geese in white or gray with faces like snow geese (the attacking goose above) are descended from greylag geese (Anser anser).

p.p.s. Sometimes the geese are fooled. In Medieval manuscripts, stained glass windows and carvings a fox dressed up as a monk or priest preaches to geese and chickens, then ultimately eats one of them. “When the fox preaches, look to your geese.“

Did you know that, when threatened, this Eurasian woodpecker uses the same distraction display as a South American flycatcher? Though the birds aren’t related their similar behavior looks like convergent evolution.

Convergent evolution is when similar traits evolve in unrelated species because they’ve had to adapt to similar environments.

A classic example is the body shape of sharks and porpoises. Both have long streamlined bodies, dorsal fins and flippers because both must swim fast to catch underwater prey.

But sharks are fish and porpoises are mammals. They aren’t related.

Here’s another example of convergent appearance.

The eastern meadowlark of North America (a member of the blackbird family Icterid) and the yellow-throated longclaw of Africa (a member of the wagtail/pipit family Motacillidae) live in similar habitats on separate continents. Though strikingly similar they are not related.

So what do you think? Is the neck-turning behavior of the Eurasian wryneck (Jynx torquilla) …

… like the distraction display of the royal flycatcher (Onychorhynchus coronatus) of Central and South America?

(Video courtesy of Cameron Rutt via Flickr; see more about this bird here).

While they’re unable to escape both birds twist their necks. Perhaps the goal is to mesmerize the predator. It looks like convergent behavior to me.

p.s. See more examples of convergent evolution at this Univ of Texas link.

(photos from Wikimedia Commons. Videos by Anders Nielsen on YouTube and courtesy of Cameron Rutt on Flickr)