Double-banded Sandgrouse as water indicator
The Double-banded Sandgrouse (Pterocles bicinctus) is commonly and colloquially called by its abbreviation ‘DBSG’ in Southern Africa. Its main distribution area is the savanna biome and especially Mopani Bushveld. There are three more species of sandgrouses in Southern Africa, all of them got distinctive different plumages but – important for us – different drinking times of water.
Specific behaviors of Double-banded Sandgrouses
DBSG’s prefer to stay in areas of short, seeding grasses speckled with bushes or other relatively open areas. They try to hide from their main predator, the Peregrine Falcon (Falco peregrinus), by camouflaging against his eyesight. This means, their color, shape and movements are adapted for optimal hiding. Plumage color in both sexes is inconspicuously speckled, streaked and barred. They are hiding their shape by a body, which looks rather flat from above and they avoid shadows by crouching and walking low to the ground. And their movement is unique for birds. They are shuffling v e r y slowly forward with very small and slow steps. See also the picture above, where first we can see this shuffling and thereafter the bird taking off. That kind of slow, linear movement (without nicking head or body) in combination with its colors and shape lets it avoid many birds of prey. But walking that slow is not an advantage if moving across a road.
How Sandgrouse chicks are drinking
And there is another wonder of nature, DBSG’s fly once a day to water for drinking. And males have got specially adapted feathers at their breast, which are able to store water. They are flying back to their chicks somewhere in the torched landscape with a speed of about 60 km/h and this stored water is not evaporating significantly. When back to the chicks, these are squeezing out the transported water with their beaks from the breast feathers. Experiments in a zoo have shown, that chicks are only able to drink water from cotton swaps, but not from open water sources or through regurgitation.
How Sandgrouses in flight can help to find water
In order to save energy and avoid birds of prey, DBSG’s are flying always in a straight line from their point of roosting to the water source. Research has shown that the peak of arriving at the water site is 16 minutes after sunset. Mostly between two and four Double-banded Sandgrouses are arriving at the same time. And average remaining time at the water source is 28 minutes.
That means, a person in the bush who is looking for water in a bushveld or scrubland savanna biome, should look for either one or two pairs of medium sized birds, which are low and fast flying a straight line around sunset or shortly afterwards. These will be DBSG’s on their way to a good-sized, permanent, and open water source.
Water drinking times of all four Sandgrouse species in Southern Africa
The various sandgrouse species fly at different times to water, but only Double-banded sandgrouses and Yellow-throated sandgrouses can normally be seen, as the other two species are flying during nighttime.
- Double-banded Sandgrouse (Pterocles bicinctus): 15′ after sunset
- Namaqua Sandgrouse (Pterocles Namaqua): 1 – 4 hours after sunset
- Burchell’s Sandgrouse (Pterocles burchelli): 3 – 5 hours after sunset
- Yellow-throated Sandgrouse (Pterocles gutturalis): early morning, always flies in flocks
Lessons learned for finding water with Double-banded Sandgrouses
- DBSG’s are flying either in pairs or two pairs very fast and low to the ground
- They fly in a straight line from roosting point to water
- They prefer permanent water sources, which are clean and where they can stand at the bottom in such a way that the water reaches up to mid-breast.