Conservationists working to re-establish rare birds of prey in Yorkshire are warning against DIY use of rat poison.

Yorkshire Red Kites says there is increasing concern about the use rat poisons, particularly those containing brodifacoum, a substance intended for controlled use indoors.

The organisation, which has released red kites on the Harewood Estate over several years, fears improper use of the poison could harm other wildlife. In its latest newsletter, Yorkshire Red Kites says more cases have emerged of illegal poisoning of kites, but also reported a successful breeding season in 2012.

The group said: “Professional advice on the use of rat poisons should ensure that the situation is properly evaluated and that the correct produce is used and properly applied. This reduces the risk of other species falling victim to their use.”

Some birds are thought to have been poisoned by baits illegally laced with poisons. A kite found in North Yorkshire in May had six poisons in its system and died after feeding on the carcass of a rabbit laced with three insecticides.

Two more birds in the county showing symptoms of alpha-chlorolose poisoning were successfully treated and released.

A total of 92 breeding pairs of kites were confirmed this year, as the birds continued to spread beyond Wharfedale, and 145 chicks were reared.

Suspected poisoning incidents should be reported to police and the Wildlife Incident Investigation Scheme on (0800) 321600. Sick and injured birds should be reported to the RSPCA on (0300) 1234999.