Ground Based Predators
The predator of most concern to many conservationists for both dormouse and bat species is the domestic cat (Felis catus). The population density of the European wildcat (Felis silvestris) is typically very low but because of human Intervention the population density of domestic and feral cats is vastly higher.
Research by Goedele Verbeylen established a minimum entrance width of 16 mm for hazel dormice (Muscardinus avellanarius) and 20 mm garden dormice (Eliomys quercinus) – carving to exactly those dimensions helps give optimum protection.
Narrow rectangular entrances, rather than round entrances, are technically more difficult to carve but likely give better safety from predation (this is currently a focus of our research).
It is thought that ground based predators hunt primarily by eye so minimising the visibility of nest holes is a high priority.
In this case, the entrance dimensions of 30 x 25 mm were planned for Eliomys and frequent visits by a pair of blue tits (Cyanistes caeruleus) during the day attracted a cat’s attention. This emphasises the importance of rectangular rather than circular entrances – dormouse species can squeeze through narrower gaps than than bird species (the minimum entrance width that a dormouse can squeeze through is determined by cranial dimensions but the minimum entrance width that a bird can squeeze through is set by sternal dimensions).
Aerial Predators
The height at which nest holes are carved can be chosen – a balance has to be achieved between getting optimum safety from ground based predators and optimum safety from aerial predators (owls and birds of prey).
References to research papers and other primary sources can be found here: References
“As climbing arborists, we exist at a unique confluence of art, science and athletics. Our profession has undergone a transformation from a dogmatic to a scientific era similar to that in medicine in the second half of the 20th century. As the challenges of biodiversity loss intensify, we find ourselves at a second turning point: we change from being consumers of research to leaders of the fundamental research and of the practical advances needed to ensure that trees remain homes to our most beautiful and endangered creatures.”
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From the tree crowns of an Irish forest I’d like to welcome you. At time of writing in July 2024 we’re focused on field studies, rehabilitation studies, bat counts and trying to work out what best to do after a devastating series of wildfires affecting Myomimus roachi in autumn 2023 and summer 2024 so this is just a basic site and we’ll be adding a lot more detail on species, people and techniques in English, German, French and Italian in autumn 2024. 🙂
Will 🌳🌲❤
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