In an earlier blog post that I had written, I talked about how urban wildlife depends on a unique combination of naturally occurring and human-generated food. In most cities of the globe, it is not uncommon to witness birds and mammals benefitting from anthropogenic food resources. This food may be derived either by intentional feeding when humans feed wildlife in urban parks, religious places, street pavements, etc., or by unintentional feeding when discarded food is accessed by wildlife from waste bins and garbage dumps. The draw of anthropogenic food resources and the availability of a wide range of habitats that the city offers has caused several species of wildlife to thrive in the city. As a matter of fact, several species are able to continuously adjust ecologically and behaviourally to the rapid expansion and constant transformation of the city. Ecologists have coined the word ‘synurbization’ to refer to this phenomenon, and the species exhibiting this continuous adjustment are known as synurbics 1. In this article, I wish to talk about the dependence of urban wild fauna on human-generated food, and the unique ways by which this food is obtained by city birds and animals.
The Canadian city of Toronto faces the challenge of managing raccoons that have developed an affinity for human food to the extent that they often raid garbage bins placed outside people’s homes at night to gain access to food refuse 2. The problem exacerbated to unmanageable levels in 2016 with the city launching a campaign against the four-legged omnivores. A $31 Million deal was signed between the city and a manufacturing company, and some half a million raccoon-proof garbage bins were distributed to residents of the city. The makers of the new garbage bins claimed that the bins were improved, state-of-the-art trash barrels, equipped with made-in-Germany gravity locks that provide full protection against raccoons. The project seemed to be a grand success until three months later when reports of the first raccoon break-in surfaced. The makers of the bin quickly launched an investigation and concluded that the bin that had been ravaged by the raccoons had a malfunction. However, the following months saw more and more reports of similar break-in’s, and the same excuse of malfunctioning bins continued. A journalist, who was also having trouble with raccoons decided to launch an investigation. Using a camera trap, the journalist was able to get a close look at the modus operandi of the garbage raiding city raccoons. As you will see in the footage below, clearly, team raccoon had cracked the code.
In his recent book Darwin Comes to Town (2018), Menno Schilthuizen talks about how tits – one of the species of songbirds – developed a mechanism to access milk cream from milk bottles in Europe during the early 1900s. Although birds cannot digest milk, they have a special taste for the rich layer of cream that accumulates at the top of milk. In the early 1900’s it was commonplace for milkmen to deliver uncapped bottles of milk at people’s doorstep. It was during this time that the birds began pilfering cream from the neck of milk bottles. To address this issue, milk suppliers started capping the bottles with cardboard tops. However, it wasn’t too long before the birds learnt the knack of stripping the cardboard layer by layer until the top was thin enough to be pierced with their beaks. Again, milk suppliers countered this new problem by replacing the cardboard caps with metal tops. Guess what? This countermeasure also failed because now the birds had learnt to use their beaks to make a hole in the cap, and then gradually peel off the foil in strips. People adopted other novel methods such as using heavy metal lids, rocks and cloth to provide an additional layer of protection to the existing metallic milk bottle caps, but to no avail. The problem started waning only because people started buying milk from the supermarket.
Arms for Alms
An ongoing study by Dr Anindya Sinha, a behavioural primatologist at the National Institute of Advanced Studies (NIAS), Bangalore recently presented his research findings at a conference on behaviour. The research sought to understand a novel method that a monkey species called the bonnet macaque (Macaca radiata) had adopted to obtain food from human beings. It was observed that juvenile monkeys in two subpopulations – one in Bandipur National Park 3 and the other in GKVK Campus, Bangalore – exhibited behaviour which involved coo-calls accompanied with a unique hand extension gesture to request food from human beings. The coo-calls were used only to gain the attention of the human being. At other times, when the monkey knew that it had the attention of the human being, only the hand extension gesture was used. Interestingly, the monkeys would use this unique food requesting strategy only if the human being was in possession of food. Unlike adult monkeys, the juveniles are often incapable of using aggression or snatching to obtain food from human beings, and this unique food requesting behaviour developed by them is an indication of the ability of urban wildlife to invent novel methods to access anthropogenic resources.
Examples like the ones discussed in this article are aplenty. Several species have earned the tag of ‘urban adapters’ and ‘synurbics’ because of their ecological and behavioural plasticity. Ability to harness anthropogenic resources is one of the primary means by which synurbics have successfully adapted to the fast pace and ever-changing nature of the city. As a matter of fact, these species have developed unique survival strategies that have never been documented in the wild. Studies have also shown that, because resources in the city are so abundant, urban-adapted species have enhanced rates of productivity. Unlike their conspecifics living in the wild, urban-adapted species have a higher life expectancy, faster growth, longer breeding season, more offspring and so on. Human beings have ‘intentionally’ created smart gadgets and smart cities, but have we also ‘unintentionally’ created smart animals?