Sheep tick Ixodes ricinus management on Welsh hill farms of designated conservation importance: implications for nationally declining birds

摘要

Impacts of sheep ticks Ixodes ricinus on livestock, gamebirds and wildlife are of concern across Europe. The present study describes livestock and tick management by 36 farmers from three upland sites of conservation importance in North Wales, where farmers consider that ticks have increased during the last 25 years. Sheep, average densities of 2.0 animals per ha were treated with pour-on acaricides in spring, again in July, and also when removed from the moor in autumn. Given acaricide efficacy rates, sheep were susceptible to tick bites for half the period on the moor. Sheep from 17 farms were examined for ticks. Infestations were similar between farms and in relation to the acaricide used, averaging 9.3 ticks per sheep, although they were lower where the interval between successive acaricide treatments was shorter. Repeated sampling of sheep and red grouse chicks showed no annual difference in tick burdens on grouse chicks, which averaged 6.2 ticks per chick, although there were three-fold fewer ticks on sheep in 2018 than in previous years. Tick bite rates on sheep and grouse were higher than elsewhere in the U.K. Most farmers interviewed would aim to improve their tick management using longer-lasting acaricides and treating sheep more frequently, although they would need advice and financial help, which is currently unavailable via Government funded agri-environment schemes.