How one bird improves public health

We love penguins.  We make blockbuster movies about them–Happy Feet, March of the Penguins, Madagascar Penguins, Mr Popper’s Penguins.  And the penguin related merchandise…wow.   But vultures?    Not so much. When a vulture makes an appearance in a movie, they add a sense of foreboding…something bad’s looming about.

Grant it, vultures might not have the cutest face among the birds of the world–put a turkey vulture up beside a barn owl and it’s not a fair match—but I suggest that like so many things in life, you can’t judge a book by its cover.   Today is International Vulture Awareness Day (oh yes, there IS such a thing!)  So indulge me and let me hit you with a few tidbits about these often misunderstood creatures who are an essential part of our ecosystem.

Vultures prevent the spread of disease.

King Vulture..how can you not love this face?

Vultures eat dead stuff.   It’s one reason they get a bad reputation–people find disgusting the notion of eating rotten flesh.  Yet, this act provides a valuable service.  Nature is full of dead animals who succumb to sickness, diseases, accidents, cars, starvation or are the leftover remains of predators.  Vultures are great at sniffing out these dead animals.  And, they get rid of these health hazards for us!

I will not get into a stomach-turning detail of how carcasses rot and attract nasty bacteria and how that makes it way to human populations–just trust me that if you leave enough dead flesh outside long enough, it becomes a catalyst for disease spread.

Vultures excel at gobbling up putrid flesh that would kill any other creature.  Their stomach acid is incredibly corrosive which allows them to safely consume some truly deadly disease-causing organisms like botulism, anthrax, and cholera.

Endangered and essential:  a lesson in what happens without them

Consider a real-life example of what happens when vultures disappear from an ecosystem.  Among the Hindu culture of India, cattle are considered sacred. Of an estimated 500 million cows in India, only 4% are consumed by people.(Ref 1) That means there’s a whole lot of cow carcasses to deal with, around 12 million tons annually.  When cow dies,  it is not consumed by people, but rather by the vultures. They are the waste-disposal system.

The problem for vultures began in the 1990’s when cattle in India began to be widely treated with an anti-inflammatory drug called diclofenac. (This drug is an NSAID and is also used in humans to treat inflammation such as with arthritis) The drug effectively poisoned the vultures who ate the cow’s flesh, causing them to die of kidney failure within hours (Ref 2).  Between 1992 and 2007, the population of one vulture species–the oriental white-rumped vulture–is estimated to have declined by 99.9%. (Ref 3).  Where there were once over 80 million of these vultures, the numbers are now only several thousand–the fastest population collapse of any wild bird in history, including the Dodo.(Ref 4)

What happened when the vultures disappeared and were no longer consuming dead cattle?

  • There was a build-up of carcasses which both contaminated water supplies and harbored diseases like anthrax (3)
  • The disappearance of vultures allowed other scavenger animals to take their place–namely rats and feral dogs. which carried pathogens and therefore spread diseases throughout human populations such as rabies, anthrax and plague.(1)
    • Today in India, there are an estimated 18 million feral dogs, the largest population in the world.  30,000 people die from rabies each year, more than half the world’s total.(1) 70% are children under age 15.

In response to the ‘vulture crisis’, India officially removed the drug diclofenac from market in 2006, but it continues to be available illegally in some areas.  Unfortunately, the damage has been done and it will take some time for the vulture population to rebound, if at all, to levels which will improve public health.

Note that diclofenac continues to be available in the EU and US, however it has not been linked to significant declines in vulture populations in these areas.

Take-away:  we are interconnected

While the lessons of what happened in India with the vulture population has many implications for other countries, the biggest is that it illustrates just how interconnected our ecosystems truly are. What on first glance appears to be an ugly, disgusting, ‘useless’ bird turned out to be an absolutely essential element in public health..and in ways no one would have ever predicted.   So next time you see a vulture by the side of the road enjoying some roadkill, don’t be repulsed. Rather, rejoice in the great service nature has provided–that ugly, bald bird is actually in a very real way out there improving your health!

Tidbits:

There are 23 species of vultures worldwide (14 are considered endangered or threatened). They are found on every continent except Australia & Antarctica.

Vultures are among the longest living birds in the wild–around 30 years.

Vultures mate for life.

They reproduce very slowly–they don’t reach sexual maturity until 5-7 years old and produce 1 chick every 1-2 years.

What’s a group of vultures called?  A committee, venue or volt. In flight, a flock of vultures is a kettle, and when the birds are feeding together at a carcass, the group is called a wake. So many names!

Spooky warning? Nah, they’re just enjoying sunning themselves.

REFERENCES

  1. What is a Vulture Worth?  PBS
  2. The Population Decline of Gyps Vultures in India and Nepal Has Slowed since Veterinary Use of Diclofenac was Banned, Nov 2012, Journal PLOS
  3. The truth about vultures BBC Earth
  4. Conserving South Asia’s Threatened Vultures,Save our Species
  5. BNHS, Société zoologique de Londre, 2007

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