Birds that play ‘chicken’ on roads, are attracted by fire and have long, trailing feathers? Abré J Steyn introduces the intriguing nightjars.
A fire was raging through the woodland, some distance from the pot-holed road which we were trying to slowly negotiate in the night. We were in northeastern Zambia, not far from the equator, making our laborious way to Lake Tanganyika. Then, through the smoke ahead, a bright red eye suddenly reflected back at us. We saw another and then some more, until the whole bush was alive with them. My first thought was that it was a herd of antelope, fleeing from the fire.
But when one of them shot straight up into the sky I realised it was a nightjar, attracted to the fire. We got closer, an unforgettable thing happened – in the bright, wide spotlights of my Land Cruiser four male pennant-winged nightjars performed the most beautiful aerial ballet in a visual melody of movement. The males of these dove-sized birds have unbelievably long and flexible, pennant-like feathers in the middle of their wings, which undulate rhythmically behind them in flight. It was only the second time I’d ever seen pennant-wings. Although they were attracted by the fire, we’d probably encountered a migrating flock, because those nightjars were only a few of the more than 50 we saw that night.
Flying slowly ahead of us, some stayed in the beam of our headlights for up to 10km at a time, swooping onto insects that we flushed, while we enjoyed one of the most spectacular displays in the natural world.
Unfortunately nightjars often sit on open spaces like roads, depending solely on their amazing camouflage until the last possible moment, before flying up. With fast-moving vehicles, this is usually fatal – the remains of 13 nightjars were once removed from an overheated truck at Kariba, blocking the airflow to the radiator.
Unlike other birds, nightjars have totally disappeared from areas with major roads or heavy traffic and there’s widespread concern among ornithologists about their general decline. Like the ever-decreasing bat population, they play a vital role in controlling nocturnal insects. Up to 500 mosquitoes have been found in a single nightjar’s stomach.
To equip them for this role, nightjars are marvellously adapted. Like swifts, they’re designed to catch flying insects on the wing, but unlike swifts, they must do it in the dark. Just imagine how acute their eyesight must be to see insects as small as mosquitoes in the dark. Their big eyes also have exceptional light-gathering ability.
A nightjar feeds exclusively on insects. Despite its very small bill, its enormous gape, together with the stiff bristles around its mouth, turns it into a highly effective insect trap. This enables the nightjar to consume the tiniest of midges and catch the largest beetles and moths.
To clear moth scales out of the nightjar’s mouth bristles, its middle toenail is a comb – it has peculiar saw-like notches on the underside. The nightjars’ typical moth-like flight is highly manoeuvrable and totally silent, due to their extremely soft plumage. While they have long wings, they’re capable of considerable speed and many species undertake extremely long nocturnal flights.
Nightjars and their relatives belong to the Caprimulgiformes, or “goatsuckers”, as these nocturnal birds were called by the Romans, who believed they suckled at night from goats. Without a doubt, they have the most effective camouflage of all birds.
Nightjars nest and generally rest during the day on the ground, usually among leaf-litter or on rocks, where their camouflage makes them virtually invisible as long as they keep their enormous eyes reduced to tiny slits, through which they quietly watch everything around them.
The very similar and closely related frogmouths of Australia and potoos of South America spend the day sitting motionless against a near vertical branch or trunk and with their necks stiff and held at an angle, looking exactly like broken-off stumps.
The most remarkable member in this group however, is the oilbird. Although it’s a fruit-eater, it’s the only bird in the world which, like bats, uses echolocation to navigate in the total darkness of caves up to 1,5km deep into the South American Andes, where it roosts and breeds communally.
In former times, their numbers were heavily depleted when their fat chicks were harvested by the thousand and boiled into cooking oil or to fuel oil lamps.
Although protected now, they’re still at risk due to the destruction of their forest habitat. Of the more than 70 nightjar species occurring almost worldwide, 24 live in Africa, but unfortunately only seven are found in South Africa and of these, the Natal nightjar is the most rare. Africa’s pennant-winged nightjar, together with the Central African standard-winged nightjar, must undoubtedly rank as the most spectacular nightjars in the world.
Vocal and melodious
Unlike the well-behaved children of past generations, nightjars are more often heard than seen. Some can be very vocal during clear nights in the breeding season, like the Mozambique and rufous-cheeked nightjars with their somewhat monotonous frog-like calls, and the fiery-necked nightjars. When it’s overcast, they’re usually silent.
To me, the melodious “good-Lord-deliver-us” call of the fiery-necked nightjar is one of the most beautiful night sounds of the bushveld. Whenever I hear it, it soothes my soul and carries my spirit on silent wings to a little campfire under a moonlit sky somewhere in the African bush, where voices that speak to me are just whispers from among the stars. Contact Abré J Steyn on 083 235 4822 or e-mail [email protected] |fw