Reputation: Vultures are bald, ugly, squabbling and filthy scavengers. They have no sense of smell. The world would be better off without them.

Reality: Not all vultures are bald. Some are even beautiful, especially in flight. Irrespective of appearance, they play a hugely important role as biological waste controllers. The world is better off with vultures, for sure.

With their archetypal ugliness and scavenging antics, vultures are easy to malign.

The lappet-faced vulture has an undeniably shifty appearance. When asked to picture a vulture, it is this species – with its hunched stance, naked neck and featherless scalp – that comes to mind.

But the contempt for vultures based on their alien looks and scavenging habits is quite obviously silly. There is a lot to admire about vultures.

Wildlife documentaries do not help.

The dominant motif is on the African savannah, a wake of vultures lurching, lunging and bickering over the remains of some poor mammal. One bird pulls its head out of the carcass and turns its face to camera, covered in blood and guts.

"I understand why people don't like them," says Mark Habben, curator of birds at London Zoo in the UK.

But in flight the vulture comes into its own, he says. "It's an absolutely stunning animal."

The large wings are not for flapping but for gliding.

Back in the 1960s, zoologist Colin Pennycuick climbed into a Schleicher ASK-14 powered sailplane and took to Tanzanian airspace, mostly above the Serengeti, to study the gliding flight of the white-backed vulture Gyps africanus.

As he motored along in search of targets to photograph, tawny eagles and martial eagles were occasionally attracted to his airplane "within 2-3 m of the cockpit in a somewhat menacing fashion".

Pennycuick found that the vultures could bank in impressively tight circles without falling from the sky. The size and shape of their wings allowed them to exploit "tiny (and often transient) patches of lift as early as 08.30h".

By 9.30 in the morning, the vultures were flying successfully at heights of 300m or more above the ground.

All 23 species of vulture use this thermal soaring to gain an aerial vantage. "They are looking out for a recent kill and looking out for the descent of other vultures," says Habben.

Vultures have legendary long-distance vision, but they may not be able to see in front of them at all. Whilst some birds have a field of view approaching 360°, the visual field of vultures is severely limited at around 60°.

That may sound silly, but vultures' insensitivity to anything above the horizontal effectively eliminates the blinding glare from the Sun, helping them to focus on what's going on beneath them.

This may also explain why vultures have prominent supra-orbital ridges (brows) and long lashes.

Vultures excel in other senses as well. In particular, anyone who believes that vultures can't smell should go and meet a turkey vulture.

In 1938, some bright spark at Union Oil in California noticed that turkey vultures seemed to be homing in on a known leak in a gas pipeline. That suggested that the species might be used to pinpoint other sites of wastage.

In the 1960s, ornithologist Kenneth Stager of the Los Angeles County Museum of Natural History in California confirmed that turkey vultures were responding to ethanethiol. This chemical is a pungent byproduct of decaying organic matter, and energy companies use it to give odourless gas an easily identifiable smell.

At a kill, things do admittedly get a little ugly. The competition can be fierce and fights are inevitable.

Feeding itself is not particularly well-mannered. Vultures often dine out on the dead animal's eyes and anus before moving on to less penetrable tissues.

The blood from the carcasses helps explain why most vultures come close to baldness. "It would destroy the feathers," says Habben, whereas blood on skin will just dry and flake off.

The bearded vulture, which prefers bones to flesh, has kept its feathered head.

Perhaps you're still not convinced about vultures. If they disappeared, would anyone really miss them?

The unequivocal answer to this question comes from India, where cattle have been widely treated with an anti-inflammatory drug called diclofenac. This drug has effectively poisoned vultures that dined out on the cattle's remains.

Between 1992 and 2007, the population of oriental white-rumped vultures is estimated to have declined by 99.9%. Long-billed vultures and slender-billed vultures suffered a similar fate.

In the absence of vultures, there was a build-up of carcasses. These posed a significant risk to human health, as they both harboured deadly diseases like anthrax and contaminated water sources.

The decaying cattle remains also resulted in an explosion of the feral dog population, rising from around 20 million to 30 million in the course of a decade. It's been estimated that the ensuing increase in rabies cases cost over $30 billion.

Vultures are biological waste controllers. "Without them the consequences are significant," says Habben. "We need them more than we recognise."