Merlins are Britain's smallest falcon and are declining on upland breeding grounds from habitat management, persecution, and climate change affecting prey.
Merlins affected by illegal persecution on managed grouse moors suffer acute injury and death. Habitat loss from conifer afforestation displaces pairs from traditional nesting areas. Climate-driven changes to upland vegetation reduce meadow pipit populations, the primary merlin prey, causing nutritional stress during breeding. Chicks in years of prey scarcity face slow starvation. Adults expending more energy searching for prey in degraded habitats are in poorer body condition entering winter.