SINGAPORE - Where the food is, so the pigeons will be.
This was a finding from a new study by the National Parks Board (NParks), which found that food availability could also have a knock-on effect on the reproductive cycles of these birds.
Using the circuit breaker as a natural experiment, the scientists found that during that period, feral pigeons spent more time foraging instead of resting.
This would have repercussions on their reproductive capacity, said NParks' Dr Malcolm Soh, the study's lead researcher who has done research on urban birds that are often considered pests.
"The results suggest that by limiting food resources islandwide, it would likely result in an eventual decline in the feral pigeon population," said Dr Soh, a senior researcher for wildlife management research at NParks.
During the two-month circuit breaker period which started last April, all non-essential activities were halted and people were urged to stay home to stop the spread of Covid-19.
Dr Soh said that "as someone who is always on the lookout for pigeons", he noticed a decline in their numbers during his trips to and from the supermarket.
This observation, as well as his scientific background, prompted him to probe this phenomenon more rigorously.
He said: "The circuit breaker provided an unprecedented opportunity to examine pest bird responses to an islandwide reduction in human traffic and food." This opportunity was previously not available, he said, and thus this is the first such study in Singapore.
The researchers identified four types of locations where pigeons are known to gather for human food - open food centres, refuse collection centres, urban green spaces and feeding hot spots - and conducted surveys at these areas islandwide.
The surveys were carried out by individual researchers who were also deployed as safe distancing ambassadors, Dr Soh said.
He also explained that applied research is employed as part of wildlife management, an essential service by NParks.
The data, as well as information collected from surveys done before and after the circuit breaker, was then analysed using statistical tools. The results showed that pigeon numbers fell the most significantly at open food centres. Dining out was not allowed during the circuit breaker.
There was also a drop in numbers at pigeon feeding hot spots, but this decline was not as significant as at the open food centres as feeding behaviour was still observed, said Dr Soh.
Their numbers went up at refuse collection centres - likely because less frequent cleaning was done during the circuit breaker due to prevailing social restrictions - and also at urban green spaces.
Dr Soh acknowledged that people may feed the birds out of kindness. But he said that pigeons, like all wild animals, were capable of finding their own food. "As our study showed, when there were fewer human food sources during the circuit breaker, the birds went elsewhere to look for food. Wild animals will not starve," he said.