Voltage and Vultures: how a shocking threat is causing their decline
Vultures are extremely vital to ecosystems and their health, and yet, they are also extremely under-valued. These birds may not look magnificent or 'pretty' to most people, but their purpose far outweighs their need to look the part. On a global scale, vultures are in fact the most threatened group of birds, and without them, environments in which they occur would become overrun with waste and disease! They are often labelled as 'natures cleanup crew' as they feed on carrion and carcasses. In the Masai Mara alone, vultures consume 70% of the deceased biomass! In fact, their role as scavengers in African ecosystems is so significant, that they are thought to consume more carrion than any other mammalian scavengers such as jackals or hyenas! Thanks to their incredible digestive system, vultures are able to ingest and process bacterial agents responsible for anthrax, cholera, tuberculosis, botulism, and even rabies without getting sick themselves. So, these birds really do play a huge ecological role as disease-barriers by ingesting toxins and safely removing them from the environment! This reduces the risk of epidemic disease outbreaks and keeps ecosystems clean and healthy.
Despite this important role, over the last two decades, global vulture populations have endured an immense decline in numbers driven by human activities and climate change. In Asia (Pakistan, India, and Nepal) vulture numbers declined by a shocking 98% over a 20 year period due to a single cause: an anti-inflammatory pain relieving medication for cattle and humans called diclofenac. The impact of which was recognized in 1999, and in the early 2000's conservation efforts helped to ban the use of the veterinary drug, establish rehabilitation programs and breeding colonies, and create protected areas known as 'vulture safe zones' to aid in their recovery. Since the ban was enforced in 2012, vulture populations have slowly been stabilizing again across Asia. However, unlike the conservation success seen across Asia, where the threat was caused by a single factor, African vultures have multiple drivers to blame for their rapid decline.
Out of the 22 vulture species currently in existence, Africa supports 11 species, 7 of which are facing extinction. This is due to a variety of threats which include poisoning, persecution, belief-based use, electrocution, and habitat loss. Over the last 30 years, Africa has lost 95% of its vultures. Currently, poisoning is the biggest factor, but records from various organisations such as VulPro, Birdlife International and other independent studies show that vulture mortality rates are on the rise due to electrocution and collisions suffered from electrical power lines. Globally, these man-made structures cause some of the highest rates of non-natural deaths in avian species, in particular in larger-bodied birds. In South Africa, almost half of the time these encounters result in death, and it's estimated that only 10% of these cases are even reported. This makes quantifying the overall impact that these electrical structures are having on vulture populations extremely hard. Studies have also shown that two-thirds of Cape Vultures (Gyps coprotheres), which are listed as Endangered by the IUCN, are killed at power lines. Current population models also predict that this vulture species could go extinct within the next 20-35 years in areas with extensive electrical infrastructure. Why are these mortality rates so high in vulture species? This is because of their large wingspan, which makes it easy for them to come in contact with the components needed to create an electrical current. As highly social animals, they tend to favour power lines to congregate and perch on, as well as using them as roosting sites.
With an annual network growth of 5%, the development of electrical infrastructures such as power lines and wind farms is expanding across the African continent. This is especially prevalent in Southern & North Africa due to growing energy demands, making this threat an important contributor in the decrease of current vulture ranges and numbers. However, there is hope! Conservation organisations have started working with energy companies and governments in various countries to make power lines and other energy infrastructures more bird-friendly. Simple and inexpensive insulation materials can be retrofitted to reduce injury and death, such as perch deterrents and deflectors, as well as insulating materials, which could help to decrease annual mortality rates by over half. This is being achieved by conducting power line surveys to determine areas of high-risk power lines. These surveys are important as they help to create an understanding of the collision and electrocution risks to birds of prey and vulture species. You can help by donating or even volunteering with organisations that have ongoing projects aimed at conserving and protecting vultures, such as Birdlife International, VulPro, or the Endangered Wildlife Trust.