Different bat species are known to differ in their detectability. Having available presence-absence data from 100 randomly stratified selected 1 km² squares in the north of the Netherlands, collected during autumn 2009 and spring 2010 following Environmental Impact Assessment protocols, we calculated probabilities of occupancy and detection for ten bat species. Not only did we investigate their presence in general but also of the three main functions a landscape has for a bat: roosting, commuting and foraging. The four most commonly detected species were Pipistrellus pipistrellus, Pipistrellus nathusii, Eptesicus serotinus and Myotis daubentonii. For all species, roosting was the function detected least while the function of foraging was detected most for most species. Probability of detection was highest for P. pipistrellus (0.79), followed by P. nathusii and E. serotinus. They are all relatively loud species, whose presence is hardly missed. For the other seven species, probability of detection was below 0.4 with the lowest value for Plecotus auritus (0.11). The latter species has a very soft echolocation call and is thus often not detected even when present. Our study is the first to use occupancy modelling for European bats. Our results show that the number of visits required to obtain a reliable approximation of occupancy differs widely: from two visits for both Pipistrellus species, to three for E. serotinus and M. daubentonii and even ten for P. auritus. Especially for the latter species, other survey methods may be better employed. This has implications for the design of surveys for Environmental Impact Assessments.

已知不同的蝙蝠物种的可检测性不同。根据环境影响评估协议，我们在 2009 年秋季和 2010 年春季收集了荷兰北部100 个随机分层选择的 1 km ²方格的存在与不存在数据，我们计算了 10 个蝙蝠物种的占用和检测概率。我们不仅调查了它们的普遍存在，还调查了蝙蝠的三个主要功能：栖息、通勤和觅食。四种最常见的物种是Pipistrellus pipistrellus、Pipistrellus nathusii、Eptesicus serotinus和Myotis daubentonii. 对于所有物种，栖息是检测到最少的功能，而对于大多数物种来说，觅食功能检测到最多。P. pipistrellus的检测概率最高（0.79），其次是P. nathusii和E. serotinus。它们都是相对响亮的物种，几乎不会错过它们的存在。对于其他七个物种，检测概率低于 0.4，Plecotus auritus的值最低（0.11）。后一种物种具有非常柔和的回声定位呼叫，因此即使存在也经常无法检测到。我们的研究是第一个对欧洲蝙蝠使用占用模型的研究。我们的结果表明，获得可靠的入住率近似值所需的访问次数差异很大：从两次访问Pipistrellus种，E. serotinus和M. daubentonii为 3个，P. auritus为 10 个。特别是对于后一种物种，可能更好地采用其他调查方法。这对环境影响评估调查的设计有影响。