We use two mitochondrial DNA fragments with different substitution rates (cytochrome b gene and the control region) to address the following phylogeographic questions about western Palaearctic populations of the barbastelle bat (Barbastella barbastellus): 1) Do the Iberian populations of barbastelles show any genetic discontinuity associated with its present fragmented distribution?, 2) Is the Gibraltar Strait an effective barrier to gene flow for barbastelles? and 3) Is the subspecies from the Canary Islands genetically distinct from continental barbastelles? Our molecular survey shows that there is only a shallow genetic structure among populations of the Iberian Peninsula and Morocco, and probably, even across Europe until Thrace, although this last point needs to be confirmed. The Gibraltar Strait has not played any significant role as a biogeographic barrier to prevent the recent passage of European barbastelles to Morocco (or vice versa). Our phylogenetic reconstructions also confirm the taxonomic distinction of B. barbastellus guanchae as an endemic subspecies confined to the Canary Islands. The precise origin of this Canarian taxon is, nevertheless, still unclear as its mitochondrial lineage is distinct from any lineage found so far in Morocco and Iberia. This important genetic distinctness suggests either a relatively ancient colonization of the Canary Islands or that the source population of the founders have not yet been identified.

We studied the impact of predation risk on emergence behavior of a maternity colony of Eptesicus serotinus. Observations were made during sets of three consecutive nights — control, treatment and post-treatment. On treatment nights, a trained individual of barn owl (Tyto alba) was displayed during the emergence of the colony. Presence of the owl did not induce any significant change in the emergence parameters with exception of the degree of clustering. In pregnancy bats increased their clustering during treatment and post-treatment nights. The presence of the owl induced changes in relationships among emergence parameters. If bats emerged earlier when predation risk supposed to be higher, they increased their degree of clustering to decrease the individuals' probability of being attacked. We conclude that clustering in emergence is an important anti-predation strategy.

We tested the hypothesis that clustering in the behaviour of emerging bats is a response to the risk of avian predation. We hypothesised that if avian predation was the cause of clustering, bats in the prolonged absence of avian predators, would not cluster or would cluster less during their emergences. We studied the Azorean bat (Nyctalus azoreum) in the Azores Archipelago. The Azores have a depauperate fauna with no raptorial birds likely to predate bats. The Azorean bat is an endemic mammal to the archipelago, which has an unusually extensive degree of diurnal activity that has been hypothesised to reflect release from the risk of diurnal predation by raptors. Contrary to our prediction Azorean bats clustered during emergence to the same extent as bat species which occur where there are raptors. Two interpretations of these data are possible. First, the hypothesis that the behaviour is anti-predatory may be incorrect. Most of the variation in clustering was explained by variation in ambient temperature possibly suggesting the bats emerged in groups to aid exploitation of sparsely distributed food. Alternatively, the behaviour may be anti-predatory, but the key factor precipitating clustering may not be the risk from aerial predators, but terrestrial predators, such as rats (Rattus norvegicus) and cats (Felis cattus), both of which were common around the roost sites.

Faeces of Myotis capaccinii were collected from four individuals netted in a spring colony in Denia, Alicante (south-eastern Iberian Peninsula). Faecal analysis revealed the presence of fish scales and bones in all droppings examined (two pellets for each individual, i.e., n = 8), with volumes ranging 6-82.5 % of prey remains. Remains of Diptera and Trichoptera were also found. These data provide the first evidence of piscivory in M. capaccinii, and reveal that this may be an important feeding behaviour in this species, at least locally and/or seasonally.

We identified 25 studies published between 1988 and 2001 that measured characteristics of roosting sites of tree-roosting bats, and where measures were compared to characteristics of random or available locations. The most frequently measured habitat characteristics were roost-tree diameter (n = 23), roost-tree height (21), roost-tree canopy cover (16), roost height (14), and slope (10). Habitat characteristics of the roost tree itself were measured more frequently than stand or landscape characteristics; a total of 31 different habitat characteristics was used to describe stand or landscape conditions as opposed to 23 different habitat characteristics used to describe features of the roost tree. The overall mean (± SE) number of habitat characteristics examined per study was 8.0 ± 1.1, with an average of 4.2 ± 0.7 characteristics reported to be significant (P < 0.05). Mean estimated effect size, or the absolute value of the difference between means divided by the population standard deviation, of habitat characteristics ranged from 0.83 to 1.52. A sample size of 11 radio-tagged bats was sufficient to achieve acceptable power, i.e., 0.80, for all habitat characteristics examined when only using the upper limit of the 95% confidence intervals for estimated effect sizes. In contrast, a sample size of 39 radio-tagged bats was sufficient in achieving the same level of power for only 50% of the habitat characteristics evaluated at the lower end of the 95% confidence intervals. We encourage researchers to conduct pilot studies, and estimate effect sizes and variances to assess the level of sampling effort required to evaluate habitat characteristics in studies of tree-roosting bats.

The structure of the calls made by the echolocating fruit bat Rousettus aegyptiacus while flying within a flight tunnel were investigated. Calls are impulsive clicks lasting around 250 μs, with most energy occurring during the first 100 μs. Such a call duration is much shorter than that previously reported for this species. The ability of R. aegyptiacus to detect and avoid obstacles was tested in both the light and total darkness. Bats were able to detect and avoid 6 mm diameter wires significantly more often than 1.3 mm diameter wires when tested in the light. In the dark, the same relationship held, with no decrease in the ability to detect and avoid the obstacles. Bats used echolocation in both the light and the dark conditions. The simple impulsive clicks used in echolocation by this species are thus able to detect wires of at least 6 mm in diameter and probably smaller. The detection problems associated with very short duration signals is discussed. The possession of both a good visual system, and a good echolocation system in this species has implications for the evolution of echolocation in bats.

Ultrasound calls made by adult Rhinolophus ferrumequinum in a nursery roost were recorded using a time expansion detector with a microphone on an extension cable. Initial analysis showed that in addition to the echolocation calls at 81–84 kHz there were ultrasound calls at lower frequencies. Simultaneous recordings of ultrasound and low frequency signals (1–10 kHz) showed that echolocation pulses, ultrasound social calls and low frequency social calls were quite distinct in both duration, frequency and number of calls. Twelve types of ultrasound social calls were identified. The majority of calls were in the range 20–29 kHz and 1–49 ms duration. Variability was found in the relative power of the fundamental and harmonics of the calls. This analysis has identified a substantial repertoire of calls used by R. ferrumequinum in a nursery roost colony. The possibility of the use of a male advertisement call in the roost is discussed.

To date, much of the research that has used ultrasonic detectors as a tool to address questions on the spatial and temporal distribution of bat species activity have been limited by the lack of a reliable and quantifiable unit of activity, and a poor understanding of sampling intensity required to accurately assess site-specific activity levels. Here it is demonstrated that file size (i.e., bytes) of Anabat-recorded echolocation sequences of the little brown bat (Myotis lucifugus) was highly correlated with the number of calls, and was easily determined, and therefore represents a reliable and quantifiable unit of echolocation activity. Additionally, it is shown that accurate quantification of a site-specific magnitude of M. lucifugus activity may not be possible, even with a sampling intensity of up to 20 nights. As a result, ultrasonic monitoring studies must be designed to minimize the effects of the high variability in bat species activity at a site among nights.

In July 2002, several bats of the genus Plecotus (Geoffroy, 1818) were captured at two localities of ‘Ordesa y Monte Perdido’ National Park (Central Pyrenees, Spain). They showed external characters that appeared intermediate between those of P. auritus and P. austriacus. Morphometric and genetic analysis have revealed that these long-eared bats should be ascribed to the recently recognized species P. macrobullaris. This study extends the distribution of this new species, whose western limit was considered, until now, to lie in the Alps, and adds a new mammal species to the Iberian fauna.

Only one species of bat, Molossus molossus, previously has been documented as occurring on the northern Lesser Antillean island of Nevis. Field research and reviews of existing museum collections have provided documentation based on voucher specimens for an additional seven species occurring on the island — Noctilio leporinus, Brachyphylla cavernarum, Monophyllus plethodon, Ardops nichollsi, Artibeus jamaicensis, Natalus stramineus, and Tadarida brasiliensis. The biological diversity of the chiropteran fauna on Nevis is similar to that found on other islands in the northern Lesser Antilles. Ecologically, this is a simple chiropteran fauna, including one piscivore (N. leporinus), one omnivore (B. cavernarum), one pollenivore/nectivore (M. plethodon), two frugivores (A. nichollsi, A. jamaicensis), and three insectivorous species (N. stramineus, T. brasiliensis, M. molossus). Species-area and species-elevation analyses for the chiropteran fauna of the Greater and Lesser Antillean islands gave r² values of 0.74 and 0.33, respectively. In the species-area analysis the bat fauna of Nevis falls above the regression line and in the species-elevation analysis it falls almost on the line. The chiropteran fauna of Nevis lies outside the Lesser Antillean Faunal Core and would be best characterized as a generalized Lesser Antillean fauna that appears to be characteristic of the northern Lesser Antilles.