Brown long-eared bat Plecotus auritus

BNrown long-eared bat - click to enlargeThe brown long-eared bat is quite common in Northern Ireland. It is instantly recognisable by huge ears that are almost half the length of its body. These long ears enable the bat to listen for insects on leaves and branches. The upper fur is light brown and the underside is paler. Brown long-eared bats forage within trees and shrubs. They roost in small numbers, usually in roof spaces. During the winter months, the brown long-eared bat hibernates.

SPECIES DESCRIPTION: The brown long-eared bat is a small to medium-sized bat with light brown fur on top and a much lighter, occasionally whitish, underside. The wings are very broad and semi-transparent and the face is a dark pink colour. The most conspicuous feature is the very long ears which can measure about 29-38mm. At rest, these ears are tucked underneath the forearms just leaving the tragus visible, projecting downwards. The head and body length is about 38-47mm and the forearm is about 34-42mm. Adults weigh about 7-8g although this can increase just before hibernation. Most of the summer maternity roosts are located in buildings with open roof spaces where the bats can be found roosting along the central roof beam. They are also occasionally found in tree holes. During the winter, bats hibernate singly or in small groups in recesses and cavities in buildings or hollow trees. Brown long-eared bats emerge at late dusk, normally only when its dark, approximately 50-60 minutes after sunset. Their flight is slow and fluttering. In confined spaces they are very agile and are able to hover. The mating season begins in September and may extend throughout the winter. Males attempt to defend harems. Females form maternity colonies during the summer, at which time the males are solitary. The young are born in July. Fertilisation is delayed through the hibernation period until the following spring.

KEY IDENTIFICATION FEATURES:


Brown long-eared bat - click to enlarge



© Jon Russ 2001. Text refereed by Angela Ross & Lynne Rendle.

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