This is the second in a 6-part series. Read the first part
On August 11, a 2-judge bench of Justice J B Pardiwala and Justice R Mahadevan directed that stray dogs be removed from the streets of Delhi and the National Capital Region as early as possible.
The bench had taken suo motu cognisance of a news report in the Times of India’s Delhi edition on July 28. It noted that the news item contained “very disturbing and alarming” figures and facts.
The Chief Justice of India B R Gavai later shifted the case from a two-judge Supreme Court bench to a three-judge one. The new bench, headed by Justice Vikram Nath and comprising Justices Sandeep Mehta and N V Anjaria, reserved its order on an interim plea seeking a stay on the earlier directive on August 14.
Down To Earth (DTE) wanted to probe the issue further. In nature, dogs and vultures often compete for carcasses. We wanted to understand the reason behind why dogs have become a menace for humans and non-human animals alike. Could the decline of the vulture in the 1990s have contributed to the dog’s rise?
DTE spoke to a number of experts on the matter. Here, we talk to Narendra Patil, who has worked for snow leopard conservation in Ladakh and on tiger population monitoring in central and south India.
While there is a link between vulture decline and the rise of free-ranging dogs, says Patil, that rise could not have been fuelled without the availability of food waste.
Down To Earth (DTE): What happens in an ecological niche/guild when a big predator/scavenger goes?
Narendra Patil (NP): Vultures are obligate scavengers and are highly efficient at removing carcasses. Some studies have shown that keeping vultures away makes carcasses decompose more slowly. Even when more generalist scavengers arrive (dogs, corvids and insects), they can’t remove dead animals as efficiently as vultures. This lengthens carcass persistence and boosts pathogen loads, increasing disease risk to people and wildlife.
In just a few years in the mid-1990s, India’s vulture population plummeted by over 95 per cent, dropping from roughly fifty million birds due to unintended diclofenac poisoning. A study reports a correlation between the elimination of vultures and an increase in all-cause human death rates in areas where vultures are vulnerable.
DTE: Has the decline of the vulture due to the diclofenac debacle led to the rise of free-ranging dogs? Has the availability of food led to the dog becoming a top predator?
NP: Reviews note that dog populations increase alongside vulture declines. But the availability of food waste in urban areas needs to be stressed too. Waste dumps support high dog populations in Ladakh, and food waste at tourist and military camps is the primary reason for the increase in dog populations. Rather than looking at free-ranging domestic dogs as ‘top predators,’ it is important to recognise that they live on the food subsidy around human habitations during peak winters, and the increased number of dogs becomes a threat to wildlife during summers.
DTE: Has the range of free-ranging dogs increased in India in tandem with the decline of the vulture?
NP: Decline in vulture numbers and increase in food waste are reasons for the growing free-ranging dog population. But, in this backdrop, the ineffective ABC program has also led to the free-ranging dog population slowly growing to unmanageable proportions in a few decades.
There are many reasons why ABC failed. But knowing that insufficient and ineffective sterilisation coverage causes rise in dog populations is important.
There are cases of adoption programs going wrong, when dogs were taken to areas that were free from free-ranging dogs—something analogous to pathogen spillover, in the Markha Valley of Ladakh (as reported by locals).
DTE: Is there a link between the decline of the vulture and the problem of free-ranging dogs becoming more predatory in nature?
NP: Direct behavioural change of free-ranging dogs becoming “more predatory because fewer vultures” has not been isolated, but population-level effects are observed, and free-ranging dogs are driving species extinctions.
DTE: What consequences does this have for ecosystems?
NP: Higher pathogen and vector loads become a public-health risk. Increased dog numbers definitely lead to a higher rabies/canine distemper burden and spillover to wildlife.
There is also greater predation and competition pressure on native species and livestock, and even the threat of direct attacks on humans.
DTE: How do you see this in the context of the latest SC judgement regarding stray dogs?
NP: Return of the efficient scavengers in vultures is important, but the removal of food waste and improvement of sanitation are much more urgent. Removal of free-ranging domestic dogs from wildlife areas, rural areas, and urban areas is a must, but the difficulty of their removal should be seen as an ecological challenge similar to that of removing alien invasive species. An experienced dog catcher in Ladakh had told me they can barely catch 30-35 per cent of the dogs they encounter. So, catchability is another reason for the failure of the ABC program, and it will remain a challenge even when relocating dogs to a shelter.