Cave Colonies Research Articles

Biparental incubation behavior in the domestic house-farmed swiftlets (Aerodramus sp.) in central Peninsular Malaysia

Abstract While the breeding biology of the edible-nest swiftlet Aerodramus fuciphagus has previously been studied, research has been limited to direct observations made on cave colonies and details on their incubation behavior remain unknown. Therefore, the purpose of this study was to examine the biparental investment of domestic house-farmed white-nest swiftlets Aerodramus sp. during incubation. This study was conducted at a swiftlet house farm in Bentong, Pahang, central Peninsular Malaysia, from August 2019 to July 2020. An infrared camera connected to a digital video recorder was installed inside the house farm to monitor swiftlets’ daily activities. We determined that the time required for swiftlets to incubate their eggs was 23 ± 0.73 days, while the hatching success rate was 75%. Swiftlets exhibit intermittent incubation with fluctuations in incubation rate from egg-laying until hatching. Both parents incubate equally, with males notably incubate longer at night and females in the morning. The incubation period is influenced by clutch size; parents incubating two eggs have a shorter incubation period than parents that incubating a single egg. Parents alternately exchanged incubation roles when both sexes attended the nest, which often occurred in the early morning before the first emergence period and during nightfall after swiftlets returned to their nests. We identified two behavioral signals during parental exchange: (1) volunteering to move aside and allowing the partner to incubate and (2) being forced by the partner to move aside. The information provided by this study can be useful to bird-nest farmers, who can use it to increase their swiftlet populations by reducing the fatality of nestlings and maintaining a sustainable yield of harvesting.

Avian and Skunk Predation of Ashy Storm-Petrels at Santa Cruz Island, California

Avian and mammalian predation of Ashy Storm-Petrels (Oceanodroma homochroa) were documented during monthly nest monitoring in 1995–1998 and 2005–2015 and once-per-year monitoring in 1999–2004 at 5 colonies at Santa Cruz Island, California. Throughout the study period, predation by Barn Owls (Tyto alba) was documented at the sea cave colonies, and at Orizaba Rock, and likely contributed to reduced breeding success at Bat Cave in 1995–1997. Recent predation by Common Ravens (Corvus corax) caused reduced breeding success each year in 2012–2015 at Orizaba Rock (35%–48%) and in 2013 and 2015 at Bat Cave (49%–52%). Raven predation appears to be developing into a larger long-term problem that may require additional management actions, but efforts have focused on deploying artificial nests at Bat Cave to provide more protected sites. Two sea cave colonies where skunks previously had not been detected experienced major adult mortality due to unusual predation events by island spotted skunks (Spilogale gracilis amphiala) in 2005 and 2008. At Bat Cave in 2005, 2 skunks were trapped after they had killed at least 76 Ashy Storm-Petrel adults. Prior to this mortality event, the colony contained 64–97 nests per year in 1995–1997, with low breeding success (49%–59%) related largely to organochlorine pollutants. After the skunks were caught, nest numbers increased from 19 in 2006 to 100 in 2015, with variable but generally higher breeding success (49%–90%). At Cavern Point Cove Caves in 2008, 2 skunks were trapped after killing at least 32 adults. Prior to the mortality event, this colony contained 11–17 nests per year in 1995–1997, with a lower breeding success rate of 20%–47%. Nest numbers increased from 2 in 2009 to 10 in 2015, with a variable but higher rate of breeding success (50%–80%). Skunk predation events may have been related to temporarily higher skunk populations at Santa Cruz due to low numbers of island foxes (Urocyon littoralis santacruzae). Deer mice (Peromyscus maniculatus santacruzae) were not significant predators of Ashy Storm-Petrels at Santa Cruz Island.

Bat population censusing with passive acoustics

Passive acoustic monitoring is a widely used method to identify bat species and determine spatial and temporal activity patterns. One area where acoustic methods have not yet been successfully applied, however, is in determining population counts, especially from roosts. Typically, most roost counts are obtained with thermal imagery that may be prohibitively expensive for many natural resource managers or require complex computer programming. Here, we demonstrate a new acoustic technique to estimate population size of Brazilian free-tailed bats (Tadarida brasiliensis) emerging from large cave colonies. Data were acquired across multiple nights and at 9 cave locations with different roost structures and flight behavior profiles. We used a single microphone to monitor echolocation activity and simultaneously recorded the emerging bats with thermal video. Bat abundance counts were determined from a single video frame analysis (every 10 s) and were compared to different acoustic energy measures of a 1-s long acoustic sequence recorded at the time of the analyzed video frame. For most cave locations, linear regression models successfully predicted bat emergence count based on acoustic intensity of the emerging stream. Here, we describe our method and report on its application for counting bats from different roost locations.

Local community perception towards bats (Mammalia: Chiroptera) in Caves in South central Mindanao, Philippines: Threats and Implication for conservation

In the tropics, bats are an essential component of many native ecosystems, through providing various ecological services including pollination and insect pest control, in addition to seed dispersal. Many Philippine bat species roost in caves and underground habitats. However, many caves are disturbed by people, to exploit resources for food, recreation, and mineral and guano extraction. The misunderstanding of the importance of bats to the ecosystem is also considered a threat to many cave roosting species. Understanding the conflicts between humans and ecosystems which provide essential services is important to maintain ecosystem service provision. A total of 100 local respondents from the village of Pisan, Kabacan North Cotabato in south central Mindanao were interviewed through semi-structured interviews and focus group discussions. Respondents were asked about their views, levels of knowledge, use, interaction, and awareness towards both the caves and bats in their locality. Our survey found that most of the respondents are aware of the presence of bats from the caves in their locality. Unfortunately, a large proportion of the respondents noted that bats are hunted in caves for bush meat and trade, and most people perceived bats as pest to fruit crops such as durian. These factors are among the main factors of the execution of many bat colonies in caves of south central Mindanao. In general, cave bats are under appreciated species in caves. The unregulated tourism, hunting for bush meat and trade, and guano extraction are among the alarming threats occurring for both caves and bats in the locality and possibly to other localities in the country. Furthermore, the establishment of strong and effective model conservation education programs and the strengthening the participation of local government, academic, and community are essential steps to preserve the current state of cave bats in the area.

Estimating colony sizes of emerging bats using acoustic recordings.

The decline of bats demands more widespread monitoring of populations for conservation and management. Current censusing methods are either prone to bias or require costly equipment. Here, we report a new method using passive acoustics to determine bat count census from overall acoustic amplitude of the emerging bat stream. We recorded the video and audio of an emerging colony of Mexican free-tailed bats from two cave locations across multiple nights. Instantaneous bat counts were calculated from the video frames, and the bat stream’s acoustic amplitude corresponding to each video frame was determined using three different methods for calculating acoustic intensity. We found a significant link between all three acoustic parameters and bat count, with the highest R2 of 0.742 linking RMS pressure and bat count. Additionally, the relationship between acoustics and population size at one cave location could accurately predict the population size at another cave location. The data were gathered with low-cost, easy-to-operate equipment, and the data analysis can be easily accomplished using automated scripts or with open-source acoustic software. These results are a potential first step towards creating an acoustic model to estimate bat population at large cave colonies worldwide.

Home-Range and Foraging Areas of the Dawn BatEonycteris spelaeain Agricultural Areas of Thailand

We studied the foraging behaviour of the dawn bat Eonycteris spelaea, a cave roosting nectarivore widespread in SE Asia, and principal pollinator of economically important crops. We radio-tracked 17 individuals for five to 19 nights over a three month period. The bats were from three cave colonies in agricultural habitats in southern Thailand. They traveled between one and 17.9 km ( ± SD: 4.4 km ± 5.07, median = 2.34) from their roosting cave to food sources. The mean home-range size of the individuals varied with the method used in its calculation from 518.4 ha (100% Minimum Convex Polygon, MCP) to 564.5 ha (100% Local Convex Hull method, LoCoH) and 460.8 ha (95% Kernel density estimation, KDE). The mean size of foraging areas used by the bats also varied according to the method of calculation from 14.26 ha (100% MCP), 13.25 ha (100% LoCoH) and 38.52 ha (95% KDE) and accounted for 21.9%, 20.08% and 40.5% of the respective home-range size. The bats foraged in one to three foraging areas each night. The gr...

Differences between populations of Spinturnix myoti (Acari: Mesostigmata) in breeding and non-breeding colonies of Myotis myotis (Chiroptera) in central Europe: the effect of roost type

We studied variations in the abundance of parasitic spinturnicid mites in relation to the gender, age and body condition of bats living in different habitats. Populations of Spinturnix myoti Kolenati, 1856 (Acari: Spinturnicidae), an ectoparasite of the bat Myotis myotis (Borkhausen) (Mammalia: Chiroptera), were investigated in two types of roosts differing in microclimatic conditions: caves (low temperature and high humidity) and attics (high temperature and low humidity). Our data suggest that bats from cave nursery colonies harbour more parasites than those from attic colonies, irrespective of host sex or age. In underground colonies, adult females and their young differ in the mean abundance of parasites, whereas no such differences were found in attic colonies. Non-lactating females from underground roosts and lactating females from attic colonies had similar parasite loads, were lower than those of adult lactating females from caves. A negative correlation between the host body condition index and parasite load was found only in the most infected sex/age group of bats. In spite of significant differences in parasite load, the mean abundance of particular life stages of mites seems to be independent of the type of roost occupied by the host, its sex or age. However, in attic colonies the number of female deutonymphs was twice that of male deutonymphs, whereas in cave colonies the proportions of the sexes were similar. We suggest that the microclimate of the host's roosts may influence ectoparasite abundance through pressure on the sex ratio in the nymphal stages of mites.

Contrasting genetic structure in two co-distributed species of old world fruit bat.

The fulvous fruit bat (Rousettus leschenaulti) and the greater short-nosed fruit bat (Cynopterus sphinx) are two abundant and widely co-distributed Old World fruit bats in Southeast and East Asia. The former species forms large colonies in caves while the latter roots in small groups in trees. To test whether these differences in social organization and roosting ecology are associated with contrasting patterns of gene flow, we used mtDNA and nuclear loci to characterize population genetic subdivision and phylogeographic histories in both species sampled from China, Vietnam and India. Our analyses from R. leschenaulti using both types of marker revealed little evidence of genetic structure across the study region. On the other hand, C. sphinx showed significant genetic mtDNA differentiation between the samples from India compared with China and Vietnam, as well as greater structuring of microsatellite genotypes within China. Demographic analyses indicated signatures of past rapid population expansion in both taxa, with more recent demographic growth in C. sphinx. Therefore, the relative genetic homogeneity in R. leschenaulti is unlikely to reflect past events. Instead we suggest that the absence of substructure in R. leschenaulti is a consequence of higher levels of gene flow among colonies, and that greater vagility in this species is an adaptation associated with cave roosting.

Ecology of Rabies Virus Exposure in Colonies of Brazilian Free-Tailed Bats (Tadarida brasiliensis) at Natural and Man-Made Roosts in Texas

Previous studies have investigated rabies virus (RABV) epizootiology in Brazilian free-tailed bats (Tadarida brasiliensis) in natural cave roosts. However, little is known about geographic variation in RABV exposure, or if the use of man-made roosts by this species affects enzootic RABV infection dynamics within colonies. We sampled rabies viral neutralizing antibodies in bats at three bridge and three cave roosts at multiple time points during the reproductive season to investigate temporal and roost variation in RABV exposure. We report seropositive bats in all age and sex classes with minimal geographic variation in RABV seroprevalence among Brazilian free-tailed bat colonies in south-central Texas. While roost type was not a significant predictor of RABV seroprevalence, it was significantly associated with seasonal fluctuations, suggesting patterns of exposure that differ between roosts. Temporal patterns suggest increased RABV seroprevalence after parturition in cave colonies, potentially related to an influx of susceptible young, in contrast to more uniform seroprevalence in bridge colonies. This study highlights the importance of life history and roost ecology in understanding patterns of RABV seroprevalence in colonies of the Brazilian free-tailed bat.

Variation in colony geometry modulates internal light levels in branching corals, Acropora humilis and Stylophora pistillata

Colonial photosynthetic marine organisms often exhibit morphological phenotypic plasticity. Where such plasticity leads to an improved balance between rates of photosynthesis and maintenance costs, it is likely to have adaptive significance. To explore whether such phenotypic plasticity leads to more favourable within-colony irradiance for reef-building branching corals, this relationship was investigated for two coral species Acropora humilis and Stylophora pistillata, along a depth gradient representing light habitats ranging from 500 to 25 μmol photons m−2 s−1, during 2006 at Heron Island, Great Barrier Reef (23.44°S, 151.91°E). In the present study changes in flow-modulated mass transfer co-varied with light as a function of depth. In low-light (deep) habitats, branch spacing (colony openness) in A. humilis and S. pistillata was 40–50% greater than for conspecifics in high-light environments. Also, branches of A. humilis in deep water were 40–60% shorter than in shallow water. Phenotypic changes in these two variables lead to steeper within-colony light attenuation resulting in 38% higher mean internal irradiance (at the tissue surface) in deep colonies compared to shallow colonies. The pattern of branch spacing was similar for S. pistillata, but this species displayed an alternate strategy with respect to branch length: shade adapted deep and cave colonies developed longer and thinner branches, allowing access to higher mass transfer and irradiance. Corals in cave habitats allowed 20% more irradiance compared to colonies found in the deep, and had a 47% greater proportion of irradiance compared to colonies in the shallow high-light environment. Such phenotypic regulation of internal light levels on branch surfaces partly explains the broad light niches of many branching coral species.

Thermal Imaging Reveals Significantly Smaller Brazilian Free-Tailed Bat Colonies Than Previously Estimated

Using data collected with thermal imaging technology, we found a major reduction in population estimates of colony size in the Brazilian free-tailed bat (Tadarida brasiliensis) from 54 million, obtained in 1957 without this technology, to 4 million in 6 major cave colonies in the southwestern United States. The 1957 census was based on human visual observations of cave emergence flights that were subject to potentially high errors. The recent census was produced using an accurate, reproducible counting method and based on complete temporal records of colony emergences. Analysis of emergence flights from dusk through darkness also revealed patterns in group behavior that would be difficult to capture without thermal infrared technology. Flow patterns of bats during emergence flights exhibited characteristic single, double, or triple episodes, with the peak flow during the 1st episode. A consistent rhythmic pattern of flow episodes and pauses was revealed across colonies and was independent of emergence tempo.

Greater spear-nosed bats discriminate group mates by vocalizations

Individuals often benefit from identifying their prospective social partners. Some species that live in stable social groups discriminate between their group mates and others, basing this distinction on calls that differ among individuals. Vocalizations that differ between social groups are much less common, and few studies have demonstrated that animals use group-distinctive calls to identify group mates. Female greater spear-nosed bats,Phyllostomus hastatus, live in stable groups of unrelated bats and give audible frequency, broadband calls termed screech calls when departing from the roost and at foraging sites. Previous field observations suggested that bats give screech calls to coordinate movements among group members. Prior acoustic analyses of 12 acoustic variables found group differences but not individual differences. Here, we use the same acoustic variables to compare calls from three cave colonies, and find that calls differ between caves. We also report results from field and laboratory playback experiments designed to test whether bats use acoustic differences to discriminate calls from different colonies, groups or individuals. Results from field playbacks indicate that response depends on the cave of origin, indicating that bats can discriminate among calls from different caves. This discrimination ability may be based, in part, on whether calls are familiar or unfamiliar to the listening bats. Laboratory playbacks demonstrate that bats discriminate calls given by their group mates from calls given by other bats from the same cave irrespective of familiarity. However, these experiments provide no evidence that bats discriminate among individuals. Previous field work indicates that females that forage with social group mates may benefit from shared information about food or mutual defence of feeding sites. Indicating group membership is essential, since these benefits appear to be restricted to group mates.

Vocal learning by greater spear-nosed bats.

Vocal learning is well known among passerine and psittacine birds, but most data on mammals are equivocal. Specific benefits of vocal learning are poorly understood for most species. One case where vocal learning should be favoured by selection is where calls indicate group membership and group mates are unrelated. Female greater spear-nosed bats, Phyllostomus hastatus, live in stable groups of unrelated bats and use loud, broadband calls to coordinate foraging movements of social group mates. Bats benefit from group foraging. Calls differ between female social groups and cave colonies, and playback experiments demonstrate that bats perceive these acoustic differences. Here I show that the group distinctive structure of calls arises through vocal learning. Females change call structure when group composition changes, resulting in increased similarity among new social group mates. Comparisons of transfers with age-matched half-sibs indicate that call changes are not simply due to maturation, the physical environment or heredity. These results suggest that studies testing vocal learning in mammals could profit by focusing on vocalizations that signify group membership.

Observations on Seasonal Cycle, Population Patterns and Roost Selection in Summer Colonies of Plecotus townsendii virginianus in Kentucky

-Limited information is available on the use of summer roosts by Virginia big-eared bats (Plecotus townsendii virginianus) or on the timing of the summer reproductive cycle for this subspecies. We measured internal temperatures and structural characteristics of roosts, and used emergence counts with night vision equipment and mist netting to monitor P. t. virginianus at three maternity roosts and one bachelor roost in Kentucky, during 1990, 1991 and 1992. Structural characteristics of roosts varied. All colonies selected limestone caves except one that used a sandstone rock shelter. There were no differences in internal temperatures between the rock shelter roost and a cave roost in summer 1991. Timing of establishment of maternity colonies varied among roosts. Roost abandonment (switching) occurred with maternity colonies in caves. Females at the rock shelter roost were pregnant on 10 May and lactating on 17 June 1991; young were volant on 5 August. Bimodal activity patterns were observed at maternity roosts, except during lactation when activity of bats at roost openings persisted throughout the night. Population patterns at the bachelor roost were consistent across years. Low numbers in the bachelor roost in mid-August coincided with the descent of testes and the onset of mating activity. INTRODUCTION The Virginia big-eared bat (Plecotus townsendii virginianus) is one of two eastern subspecies of Townsend's big-eared bat (P. townsendii) listed as endangered by the U.S. Fish and Wildlife Service, because of its restricted distribution and the paucity of data on location and use of summer roosts (Bagley, 1984). The only studies of a P. t. virginianus maternity colony have reported data on activity patterns and food habits in Virginia (Dalton, 1983; Dalton et al., 1986). For the Kentucky population of P. t. virginianus, only sporadic population estimates exist for summer colonies (J. MacGregor, pers. comm.). Plecotus townsendii virginianus are vulnerable to human disturbance at summer maternity roosts (Barbour and Davis, 1969; Harvey, 1975; Bagley, 1984). This has hindered attempts to collect data on summer colonies of this subspecies; consequently, no information exists on its reproductive cycle. In this paper we report data on roost characteristics, population patterns and seasonal cycle of P. t. virginianus maternity and bachelor colonies in Kentucky. STUDY AREA AND METHODS This study was conducted in Lee County, Kentucky, within the Stanton Ranger District of Daniel Boone National Forest. Lee County is approximately 80% forested (Newton et al., 1974) and has a climate characterized by warm and humid summers and moderately cold winters. Average maximum and minimum temperatures are 34 C in August and -18 C in January (Newton et al., 1974). Average monthly precipitation is 9 cm (Newton et al., 1974). July and October are the wettest and driest months, respectively. The only known population of Plecotus townsendii virginianus in Kentucky hibernates in Present address: Cape Canaveral National Seashore, 308 Julia St., Titusville, Florida 32796

Prevalence of Trypanosoma cruzi-like infection of Colombian bats.

Schizotrypanum species were found in 4·68% of 19 885 bats of 118 species collected from 658 localities in Colombia. Among 573 blood cultures used in mouse protection tests, partially in combination with xenodiagnosis, 233 isolates were identified as T. c. cruzi, 25 as T. c. marinkellei and 315 as Schizotrypanum sp. indet. Among the common species of bats, the highest infection with Schizotrypanum spp. was found in Noctilio labialis (50·0%), Artibeus lituratus (48·8%) and Phyllostomus hastatus (39·3%).Five T. c. cruzi isolates from bats became highly virulent to mice after ten to 15 passages through mice or after passages through tissue cultures.Intra-or peri-domiciliary bats were infrequently infected (e.g. Molossus spp., 1·2%; Myotis spp., 1·3%; Carollia perspicillata 1·8%), as were bats that form large colonies in caves (e.g. 0·04% of 7532 bats of the genera Mormoops, Natalus and Pteronotus). Bats were not infected in the areas along the Atlantic coast or above 2200 m altitude. The highest prevalence wa...

Social organization and kinship in the polygynous bat Phyllostomus hastatus

1. Social behavior in the bat Phyllostomus hastatus was examined in Trinidad, W.I. over a 26-month period. The studies included (a) long-term observations on marked individuals, (b) the use of allozyme polymorphisms to estimate paternity and the genetic relationships among individuals in social groups, and (c) the investigation of foraging behavior by radio-tracking. 2. Day-roosting cave colonies of this bat are subdivided into highly stable, compact clusters of adult females (mean cluster size=17.9±5.1 females) and less stable bachelor groups. Female clusters are always tended by a single adult male and genetic tests demonstrated that these harem males father most or all of the babies born to the females in clusters. Harem males actively defend female clusters from other males in the roost. 3. Membership in female clusters is extremely stable and the same individuals roost together for years at a time. Harem male tenure can also be very long and several males retained residence in harems through a minimum of three annual reproductive periods. However, harem male turnovers were also frequently observed and in no instance did a change in males result in disruption of the female roosting cluster. Experimentally disrupted harems reconstituted their original memberships even in the absence of males. 4. These stable female clusters are not matrilineal kin groups. Juveniles of both sexes disperse and are not recruited into parental social units. New stable female clusters were formed as cohorts of yearling females drawn from different harems and cave colonies. This was corroborated by independent studies on the age structure of harems. Genetic tests showed that the females comprising any cluster were a genetically random sample of the total adult population. 5. Radio-tracking revealed that each individual has its own foraging area that it utilizes throughout the year. The foraging areas of females belonging to the same cluster were adjacent to one another and apparently segregated into larger cluster-specific areas. Females occasionally foraged within the areas of other females in their roosting cluster, but females from different clusters did not forage near one another. Harem males did not defend female foraging areas and in fact foraged in areas well apart from their harem females. 6. These compact and stable female roosting clusters are the fundamental unit of P. hastatus' social organization, and apparently they facilitate a male strategy of female-defense polygamy. We hypothesize that these stable clusters arise from active cooperative interactions among females on the foraging grounds. The most likely form of cooperation is the sharing of unpredictable food sources among cluster members. In P. hastatus, such behavior has not evolved through nepotism or processes of group selection that require high group stability. All of our observations and the basic biology of this bat suggest that reciprocity is the most likely means by which the system operates. Mutualism and weak altruism may play secondary roles but cannot be evaluated without additional field study. 7. Bachelor groups appear to be much less structured than female clusters, and the possibility of cooperation among bachelors is still open to study.

Seasonal Populations and Movements of the Gray Bat in the Kentucky Area

During studies of bat populations of about 100 caves in the Kentucky area, a hibernating colony of about 100,000 gray bats, Myotis grisescens, was found in a cave in Edmonson County, Kentucky. Summe.r colonies were found in 10 caves in Kentucky, Illinois, and Tennessee. Of 3,072 gray bats banded in the winter colony only 12 were recovered in the summer, with one movement of 102 miles. Of 1,622 banded in six summer colonies in Kentucky and Illinois, 153, or 9.4% we-re recovered in the hibernating colony in Edmonson County, Kentucky. These various summer colonies from which bats moved to the one hibernating colony are scattered over an area of about 10,500 square miles of Kentucky, southern Illinois, and northern Tennessee.. The gray bat, Myotis grisescens, has a limited distribution in eastern and southern United States. It has been collected in the following 11 states: Illinois; southern Indiana; Kentucky; Tennessee; Alabama; northern Florida; northern Arkansas; northwestern Oklahoma; Missouri; eastern Kansas; and southwestern Virginia (Hall and Kelson, 1959; Long, 1961; Holsinger, 1964). Most reports of this species concern summer colonies in caves, usually colonies of females rearing their young. Such colonies have been reported in northwestern Arkansas from Benton and Madison Cos. (Black, 1936), northeastern Oklahoma in Adair Co. (Glass, 1955), central Missouri in Boone Co. (Guthrie, 1933), southeastern Tennessee in Marion Co. (Mohr, 1933), and northern Florida in Jackson Co. (Rice, 1955). The sizes of these summer colonies have been reported either as being large or as containing 1,000 to 6,000 individuals. These authors have also noted seasonal movement. The caves that contain summer colonies usually have been found to contain no bats or only a few individuals in winter. A few winter colonies have been reported: Sealander and Young (1955) found M. grisescens in five caves in Arkansas in winter, in Washington Co. (October), Benton Co. (December), Madison Co. (November, December), and Stone Co. (October). Sizes of these colonies are not reported. Bole (1943) reported that a series of M. grisescens was taken from a cave in Grainger Co., Tennessee, on '24 December 1911. Glass (1955) reported the species present in a cave in Adair Co., Oklahoma, in winter. Guthrie (1933) states that only a few are found in the caves of Boone Co., Missouri, in winter. Jennings and Layne (1957) reported 1,200 M. grisescens in a cave in Jackson Co., Florida, in October 1955 and a smaller number in February 1956. Nothing has been published concerning the size of colonies, sea-