Stalkers right to shoot orphan deer
Young deer should also be killed when their mothers are shot, according to scientists.
Research carried out on the Isle of Rum in Scotland showed that orphaned deer were much less likely to survive than those with their mother's care.
Young males that were orphaned in their first year were slow to grow antlers, indicating a potential lifelong impact.
The results support best practice guidelines in Scotland where deer are culled to control populations.
The study was supported by the UK Natural Environment Research Council, the Natural Sciences and Engineering Research Council of Canada and Scottish Natural Heritage (SNH).
It is published in the journal Behavioural Ecology and Sociobiology.
According to reports commissioned by SNH, there are between 350,000 and 400,000 red deer in Scotland.
Without wild predators to control the numbers, populations are now managed in particular areas where deer have caused issues.
"Red deer are an iconic species in Scotland and they bring an awful lot of benefit to our biodiversity and tourism... but they've also got the potential to impact adversely on natural habitats, public safety, woodland [and] agricultural crops," explained Robbie Kernahan, wildlife operations manager for SNH.
To manage populations, 60,000 red deer on average are shot by deer stalkers every year as part of organised culls and land management.
"25,000 of those are stags, 25,000 are hinds and the remaining 10,000 are calves," said Mr Kernahan.
Prof Josephine Pemberton from the University of Edinburgh and colleagues conducted their study on the Isle of Rum in the Inner Hebrides, Scotland, UK where individual-based deer research has been carried out since 1972.
Young deer were caught, sexed and tagged before being returned to their mothers and monitored.
Monthly censuses and spring searches for dead deer provided data for the scientists to understand how young deer fared with and without their mothers.
End Quote Robbie Kernahan Scottish Natural Heritage
It does make strong moral sense to make sure that calves don't suffer or struggle”
Deer wean at seven months and research showed that animals that were orphaned before this age had lower survival rates.
Males that lost their mother before weaning were also found to develop their first antlers more slowly. This is known to have knock on effects for antler growth later in life and reproductive success.
Researchers also found that male deer orphaned under the age of two had an increased risk of death.
Female deer stay with their mothers so their risk of death was increased when their mother was killed regardless of age.
Mr Kernahan explained that female deer are targeted to control populations and current best practice guidelines encourage deer stalkers to avoid leaving orphans.
"When the stalking season [for females] opens in October we still have quite a lot of calves that are not exclusively nutritionally dependent on their mother but certainly socially," he said explaining that calves learn where to shelter and forage from their mothers.
"As such if you were to shoot a red deer hind without taking the calf there are obvious concerns that that calf would not be able to survive... because they rely on that maternal link to get them through the winter."
Although he was unsurprised by the results of the research Mr Kernahan said they were helpful in underpinning management decisions.
"It's strength to the arm of what we've been saying in the past. It does make strong moral sense to make sure that calves don't suffer or struggle," he said.