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4. Population trends
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The red kite suffered from intensive human persecution through much of its world range, which is mainly in Europe, until the mid-1950s, but especially so between 1850 and 1900. This resulted in the species becoming extinct in several countries following a marked long-term decrease in range and numbers.
In the UK the red kite was a valued scavenger during the Middle Ages that helped keep streets clean and was protected by a royal decree; killing a kite attracted capital punishment. However, by the 16th century a bounty was placed on its head and, in common with many other birds of prey, it was relentlessly persecuted as ‘vermin’. The persecution continued through the following centuries largely by game keepers, who wrongly accused them of taking game. As the kite became rarer, it became a target for taxidermists and egg collectors, whose actions hastened the species towards extinction. Consequently, the red kite became extinct in England in 1871 and in Scotland in 1879. By 1903 when protection efforts started, only a handful of pairs were left in remote parts of central Wales.
The small remnant population survived the persecution in the old oakwoods in the undisturbed upland valleys of mid-Wales, but despite extensive efforts, the numbers remained extremely low. The tightest genetic bottle-neck came in the 1930s. Even though several pairs survived, DNA analysis has since discovered that the entire Welsh population was derived from a single female bird. The population did not exceed 20 pairs until the 1960’s, when it started slowly to increase. There were many reasons for the slow recovery. The population inhabited an area where the climatic conditions and poor food availability depressed breeding success and prevented the birds from expanding their range. Until about 1950 when protection measures were starting to take effect, illegal poisoning, egg collecting and shooting of adults for taxidermy were severely affecting the population. During the 1950s the rabbit myxomatosis outbreak devastated a main food supply of the kites. This was followed by poor breeding success in the early 1960s, thought to be caused by effects of organochlorine pesticides. It was for a long time believed that the lack of genetic variability caused by the bottle-neck had resulted in the low reproductive rate. However, once the species had successfully spread to more productive land at lower altitudes, it became obvious that this was almost entirely due to poor habitat conditions. By the mid-1990s there were over 100 breeding pairs in Wales, and over 500 by 2006.
Due to the low rate of chick production the Welsh population appeared to be unable to spread out of Wales to recolonise its former range. The reintroduction programme run by the RSPB, Natural England and Scottish Natural Heritage, with support and sponsorship from many other bodies, started in 1989 and has helped to establish red kites in several areas of England and Scotland, and their range and numbers are slowly expanding. Consequently, the red kite’s future as a British breeding species is now much brighter.
(Source: RSPB Red Kite Information leaflet (revised 2007)