ILLEGAL killing has contributed to the slow growth of the red kite population in northern Scotland, according to a new report.

While reintroduced red kite numbers are on the rise throughout much of Scotland, with at least 283 pairs in 2015, the Scottish Natural Heritage (SNH) report found the population in the north continues to grow more slowly than elsewhere.

There are currently about 70 breeding pairs in north Scotland but officials said if there had been no illegal killing there could have been as many as 1,500 pairs.

It also estimates there could still be around 131 pairs by 2024 and, in the longer term, there could be about 550 pairs by 2044.

Of 57 dead red kites recovered between 2007 and 2014, 42 per cent were confirmed to have been illegally killed. This was similar to a study which found that 40 per cent of recovered dead birds were confirmed to have been illegally killed throughout the period from the start of the reintroduction in 1989 up to 2006.

Environment Secretary Roseanna Cunningham said: “It is, of course, good news that red kite numbers are increasing in Scotland. It must be said that it is extremely disappointing that this success is being lessened by illegal persecution of these magnificent birds. I want to be clear that wildlife crime is not acceptable in a modern Scotland.”

The study also assessed the impacts of a 2014 incident of illegal poisoning of red kites in Ross-shire in which 16 red kites were found dead, with 12 subsequently confirmed to have been poisoned.

It found that when modelled as a one-off, the incident had a relatively small impact in the short-term.

The report, commissioned by SNH and carried out by RSPB’s Centre for Conservation Science, also considered the potential risks of proposed wind farms and found there could be up to two bird deaths a year linked to the developments.

A cause of death which has occurred more regularly in recent times has been the effects of accidental poisoning from legal rodenticides.