Wild red deer on Rum are rutting earlier in the year compared with decades ago, a University study shows.
Scientists believe the annual rutting season on the Hebridean island could be changing because of warming spring and summer temperatures.
The study, carried out by scientists at Edinburgh and Cambridge, focused on a population of wild deer that featured in the BBC TV series Autumnwatch.
Although many kinds of plants and animals are known to be reproducing earlier, evidence of early reproduction in large mammals is very unusual. Much more work is needed to understand whether similar changes are taking place in deer populations elsewhere, and what the implications will be.
Scientists showed that the deer rutting and calving seasons are now up to two weeks earlier on average compared with 30 years ago.
The research was based on a 38-year study of the ecology of red deer on Rum and used annual records of breeding success in more than 3000 deer.
Scientists at the Universities of Cambridge and Edinburgh, who maintained the long-term research, say this provides rare evidence that warming temperatures are affecting the behaviour of British mammals.
The research, published in the journal Global Change Biology, was funded by the Natural Environment Research Council and supported by Scottish Natural Heritage.
We are very pleased to be supporting this latest study on Rum. It provides further evidence of how climate change is impacting on wildlife. There may be implications for deer and their management in future.