In 2017, 40 territories of Sparrowhawk were located in the province of Groningen. For two municipalities followed since 2012, numbers had declined by 33 and 50%. Twenty-five out of 39 pairs were successful in raising at least one young. Failures occurred during the egg stage (8x, of which twice predation by marten) and chick stage (1x dead chicks on nest, 5x predation by marten or Goshawk Accipiter gentilis). Among successful nests, partial predation was repeatedly recorded. Start of laying among 22 nests averaged 1 May (range 20 April – 14 May), and successful nests raised on average 3.9 chicks. Louse flies were recorded on chicks in 13 out of 22 nests.