Birds of prey found in the uplands include kestrels, hen harriers, merlins and peregrine falcons. Birds breeding here include buzzards, kestrels, merlins and peregrines, ravens and choughs. These include kestrels, merlins, hobbies, hierofalcons and peregrines. Other avian predators of adults have included peregrine falcons ("Falco peregrinus") and merlins ("Falco columbarius"). Merlins, tawny and long-eared owls also hunt goldcrests. Rare species are merlins (up to five pairs) and peregrine falcons (at least one pair). Production of short-fuselage Merlins ended in 1983 with the building of Merlin IIIC c/n TT-541. Lower-revving Griffons, compared to Merlins, reduced engine stress which improved their reliability. Heinkel He 111 twin engine bombers with imported Rolls Royce Merlins, as the CASA 2111. Cooper's hawk are also counted as a predator of merlins ("Falco columbarius"). The two outboard Rolls-Royce Merlins were replaced by the jet engine. Commando Helicopter Force at Yeovilton operates Merlins and Wildcats (the upgraded version of the Lynx). Merlins attack winter flocks, including those in cities. Sometimes, merlins cache food to eat it later. This may account for almost half of all premature deaths of merlins.