The researchers say that dogs evolved from wolves as the "top predators" in many ecosystems, having the tendency to hunt without facing any threat. As per them, the latest findings indicate that wildlife still perceives domestic dogs as a threat.
"These results support the ban on access for dog-walking to sensitive natural areas," the Telegraph quoted Dr Peter Banks, who conducted the study with Jessica Bryant at the University of New South Wales, as saying.
The researchers studied the impact of dog walking at 90 sites in woodland on the urban fringe of Sydney, and monitored the responses of many kinds of birds when they were presented with walkers with dogs, walkers without dogs and a control (neither walkers nor dogs).
The sites included in the study were those where dog walking was permitted and frequent, where birds might have become used to dogs, and national park sites where dog walking was prohibited.
A range of dog sizes and breeds, and a range of different walkers were used during the study. The dogs were kept on leads. All native birds seen or heard within 50 metres of a 250-metre trail were monitored. The monitoring commenced 20 seconds after the walker/dog-walker had set off and continued for 10 minutes.
"Dog walking caused a 41 per cent reduction in the numbers of bird individuals detected and a 35 per cent reduction in species richness compared with untreated controls. Humans walking alone also induced some disturbance but typically less than half that induced by dogs," the researchers said.
Dr. Banks said that ground dwelling birds such as painted button-quails, the fairy wrens and finches appeared most affected. He said that 50 per cent of the species recorded in control sites were absent from dog-walked sites.
Even for birds which did not flee the site, there were 76 per cent fewer individuals within 10 yards of the trail when dog walking occurred compared with control sites, suggesting that birds were seeking refuge.
"These results reveal that even dogs restrained on leads can disturb birds," they conclude, confirming the need for them not to be walked in sensitive bushland and conservation areas.
"The effect occurs even in areas where dog-walking is common and where they are prohibited, indicating that birds don't become accustomed to continued disturbance by dogs," said Dr Banks.
The revelation has immediate implications for popular recreations such as bird-watching and eco-tourism, where visitor satisfaction has a strong relationship to the number of species seen.
"The issue is here that dog walking will displace birds meaning bird watchers and ecotourists will not see as many birds, detracting from their experience...of course ecotourism without dogs still has its own impacts on wildlife," Dr Banks said.
The researchers said that dog-walking might also affect the accuracy of wildlife surveys used to map bird distributions around the world.