Little Grebe: Artwork of Evolution

Ali Hussain, BNHS’s topmost bird trapper and a great naturalist, told me to keep the little grebe on my palm, fully confident it would not fly away. I was reluctant, but he insisted. The confused bird, tagged with a BNHS ring, sat on my palm, looking at me bewildered as I admired its beautiful facial markings. The year was 1981, and I was part of the BNHS team of scientists ringing birds in Keoladeo National Park to study bird migration. After ringing and taking measurements, we released the birds. Most of the birds would fly from our hand, and few would escape even before ringing, but grebes are different. Their large, lobed feet are positioned too far back on their body to facilitate swimming, and they cannot walk on land (at the most, they can wobble a short distance) and nor can they take off from hard surfaces, which is why the bird continued to sit on my palm. After this ornithology test, we released the little grebe in the water. It swam away quickly and then took off to join its companions in the vast jheel. I accepted that bookish knowledge should be supplemented with field knowledge, which Ali Hussain had and I did not at the time.   

Species and distribution

Evolutionarily, grebes are considered ancient, along with loons (not found in India) and divers (black-throated and red-throated divers are found in India). As they are good fliers, most grebes are widespread in the world. For example, little grebes are found in Asia, Europe and Africa and occur in six or seven subspecies. Similarly, the great crested grebe is one of the most widely distributed waterbirds in the world.

We have five species of grebes in India, and the little grebe is the most widespread resident. It is a bird of small unpolluted wetlands, village ponds, and gravel pits. When disturbed, instead of flying, it dives into the water, reappearing away from the intruder. This behaviour gives it the moniker pandubbi in Hindi. Its scientific name Tachybaptus ruficollis, from Ancient Greek and Modern Latin, also speaks of its behaviour of disappearing in the water. (Takhus means fast, and bapto means to sink under; ruficollis is from Latin rufus, red, and Modern Latin collis, or neck.)

Feeding patterns

Little grebes, like all grebes, feed on aquatic insects, larvae, small fish, and frogs. Some food is caught on the water’s surface, but most of its prey is obtained underwater. The little grebe can stay underwater for 20-40 seconds. It dives into the water with a slight jump, head and neck first, followed by the stubby body. Its heavily webbed toes act like a rudder and help propel it as it pursues its equally agile prey. In shallow water, it foot-paddles and stirs up muck and hidden insects to eat.

Grebes are also known to eat feathers, generally plucked from their flanks, to help in digestion. Even chicks are fed adult feathers. The role of feathers is similar to the grit that helps many granivorous birds digest hard seeds. It has been established that the little grebe’s gizzard is insufficient to crush fish bones. Once the flesh is digested, bones remain in the stomach. The feather balls help protect the stomach walls by padding it from sharp fish bones and slow down digestion so that the bones dissolve and nutrients are absorbed by the alimentary canal.

Breeding behaviour

Where unharmed, little grebes live close to human beings. They make a nest of leaves, submerged vegetation, and floating plants. These nests are loosely anchored to the ground (in shallow areas) but, more often, float. Mating generally takes place on the nest, but sometimes it occurs on a nest platform, which is later transformed into a true nest.

The egg cup of the nest is just above the water’s surface, where the female lays 3-5 (sometimes six) white or cream-coloured eggs. Both sexes incubate, though the female probably plays a greater role. When disturbed, the little grebe leaves the nest unobtrusively and vanishes, but not before dexterously covering the eggs.

The little grebe’s main predators are crows, monitor lizards, and harriers. In some areas, carnivorous fish are the major predator, particularly to young ones. A few years ago, when invasive African catfish (Clarias gariepinus) were inadvertently introduced in Keoladeo, it played havoc with waterfowl, and many grebes left the famous jheels to nest elsewhere. A hungry fish can grab a grebe from the water below. 

As little grebes cannot walk, climbing the nest is an arduous task which it attempts by jumping on the nest, sometimes landing on its breast. The grebe will then shuffle itself to sit on the nest/eggs. Throughout the incubation period (18-20 days), both parents regularly repair the nests. It also helps keep the conjugal bond.

During the breeding period, the paired birds utter a shrill trilling twitter (though sometimes, a single, unpaired individual may also trill). Once pairing has taken place, the pair becomes quite territorial and will not allow other pairs to come near them. In a large, moderately deep wetland, each pair will have a 50-60 m radius territory around the nest where other grebes are not allowed. Fights are frequent, so in the breeding season, we can witness chases, brief fights, mock drills, and shrill calling.

Nesting strategies

In an interesting study at Wular Lake, Kashmir, published in Indian Birds (2008), Mustahson F Fazili and others found that the little grebe has two types of nesting strategies: colonial and solitary. Colonial nesting is chosen in areas with sparse growth of emergent and floating vegetation — for better visibility. Non-colonial or solitary nests were located in areas where floating vegetation was dense with occasional emergent reeds. Strangely, the hatching success of colonial breeding little grebes was lower than in non-colonial breeders, as the effect of predation was higher in the former than the latter. The main predators were humans, black-crowned night herons (Nycticorax nycticorax) and house crows (Corvus splendens). I cannot understand why birds choose to nest in groups when predation pressure is higher in colonies. Perhaps more research or better analysis of the data will reveal this secret. 

Threats

Like all waterbirds, the little grebe faces threats of habitat destruction, pollution, over-extraction of water, sudden release of water from dams, fisheries development, expansion of water hyacinth and Ipomea, trapping, and introduction of invasive carnivorous fish. Water hyacinth destroys its habitat as the little grebe nests in open waters. The little grebe is not targeted for trapping, as this little bird cannot provide much meat, but it is accidentally trapped in fishing nets. For instance, in the Bhagalpur area in 2022, I saw huge wetlands but practically no birds, as most had been trapped.

There is currently no immediate threat to this artwork of evolution, but like all other waterbirds of India, its habitat needs special protection from development activities. This ancient bird has survived for millions of years unchanged; let us hope it will continue to survive the current Anthropocene epoch.