44
D. A. Flavin et al.
There have been only 4 systematic analyses of prey remains in the faeces of
Daubenton’s bat in which the relative proportions have been expressed numerically
(Vaughan 1997). Of these, Taake (1992), working in NW Germany, analysed prey
remains in 36 faecal pellets to order with some to family. Beck (1995) examined 306
pellets from various sources in Switzerland but, while listing families and sub-
families, gave overall figures only for orders. Swift and Racey (1983) examined a
regular sample (n = 25) of droppings on each of 8 nights from a nursery roost in
Scotland and compared the results (to family) with insects available to the bats on
each night, as sampled with a suction trap. Finally, Sullivan et al. (1993) processed a
total of 120 faecal pellets over 3 months, to family, from a roost in the west of Ireland.
The present study was undertaken partly to provide further detailed data on the
diet of the species, but particularly to obtain a fuller picture of the prey taken in
summer in Ireland. In it we present data from 1091 pellets from 7 different roosts,
including, for one, results for each month from April to September over 2 years.
Study roosts
The land around all of the roosts, which are all at less than 150 m above sea level, is of good quality
and pasture predominates, as it does on most agricultural land in Ireland. The fields are generally
small and bordered by well-developed hedgerows with at least some trees.
The first 5 roosts are all in the catchment of the Blackwater River in the extreme south of Ireland,
the water here being classified mainly as unpolluted (Lucey et al. 1999). In the surrounding district
there are numerous hedgerow trees and also many blocks of both deciduous and coniferous woodland.
The first three roosts are associated with the River Blackwater itself, which here is 40–50 m wide, its
banks densely clad with deciduous trees. The roost at Convamore House (52°8’N, 8°25’W) is in the
wine cellar of a ruined mansion, within 100 m of the river. That at Glencairn Abbey (52°8’N, 8°0’W ) is
in an underground passage, 3–5 m in height, again within 100 m of the river. This was the only verified
nursery roost. The roost at Ballyhooly Bridge (52°8’N, 8°24’W) was in the stonework of the bridge
which spanned the Blackwater River. The remaining two roosts were also in the stonework of bridges:
Araglin Bridge (52°10’N, 8°13’W over the River Araglin, 15 m wide), and Licky Bridge (52°0’N, 7°48’W
over the River Licky, 10 m wide).
Dysert Bridge (52°47’N, 7°13’W), in which the bats also roost in the stonework, is in SE Ireland
and spans the Dinin River, 30 m wide at this point, with thick herbaceous cover on its banks. A recent
survey reports water quality in the various stretches of this river as varying between unpolluted and
slightly polluted (Lucey et al. 1999). At all the aforementioned bridges, the roosts are either wholly or
partially in peripheral arches, through which the river did not flow over at least part of the summer.
Blacksessiagh Bridge (54°33’N, 7°21’W), in Northern Ireland, spans the River Owenreagh, 15 m wide
here. The roost is in a blindly-ending arch, 1.5 m high, some 100 m from the bridge itself. Water
quality here is good (unpublished Government data). The Blackwater, Dinin and Owenreagh Rivers
are slow-flowing; the Araglin and Licky rivers are fast-flowing.
Material and methods
Droppings were collected on polythene sheeting, except at Glencairn Abbey where, because of high
humidity, curtain netting was used instead. There was only 1 collection at Blacksessiagh Bridge, from
15 June to 1 August 1997. At all the other sites, polythene/netting was laid at the beginning of April
1997, or, at bridge sites where water was flowing under the roost, at the beginning of the first month
after the arch was dry. Polythene was removed at the end of each month, or at the beginning of the
next one, and replaced until the end of September; thus each collection of faeces could be assigned to a
particular month. However, because of flooding, some months were unrepresented at the bridge sites.