NESTING AND BEDDING 



In summer, females need warm caves (14° to 

 27° C) for rearing young. Important characteristics 

 of bat caves include small chambers (Dvvyer 

 1963), high places in domed ceilings (Davis et al. 

 1962), or domes or small pockets within these 

 locations (Dwyer 1963, Dwyer and Hamilton- 

 Smith 1965, Dwyer and Harris 1972), and depth 

 of etching and porosity of the rock surface (Tut- 

 tle 1975b). Males, nonreproductive females, 

 postlactating females, and juveniles, also use 

 caves in summer, but not the same ones used as 

 maternity sites (Tuttle 1976b). 



RITUAL REQUIREMENTS 



Not known. 



OTHER CRITICAL ENVIRONMENTAL 

 REQUIREMENTS 



The gray bat is perhaps the U.S. mammal 

 most narrowly restricted to cave habitats (Hall 

 and Wilson 1966; Barbour and Davis 1969; Tuttle 

 1976a, 1979). For all practical purposes, it lives 

 in caves the year round (Tuttle 1979). It is essen- 

 tial that the bats choose roosts, generally caves, 

 having temperatures appropriate to the desired 

 metabolic processes: warm for digestion and 

 growth in the summer, and cool for torpor in the 

 fall and winter (Twente 1955). However, in the 

 summer, gray bats will use man-made structures 

 that simulate cave conditions (e.g., storm sewers 

 in Kansas and Illinois [Hays and Bingham 1964, 

 Elder and Gunicr 1978], and a bam in Missouri 

 [Gunicrand Elder 1971]). 



A minimal colony size is needed to maintain 

 an adequate roost environment; otherwise, the 

 colony may fail (Tuttle 1975b, 1979). Because 

 travel is such a high-energy activity, the bats need 

 summer caves close to feeding areas— usually with- 

 in 1 km and no more than 4 km from the nearest 

 feeding areas. The distances from maternity sites 

 to feeding areas are important in influencing post- 

 flight growth and survival (Tuttle 1976a). 



POPULATION TRENDS 



The estimated total population of the gray 

 bat is 1 million (Tuttle 1975a). Five major caves 

 have not been used in the past 20 years (Tuttle 

 1975a). Twenty-two summer localities in Tennes- 

 see and Alabama were censused in 1970 and again 

 in 1976. A 64% reduction in numbers was recorded 

 for this period (Tuttle 1979). The decline is attri- 

 buted mainly to a marked increase in human dis- 



turbance over that period (Tuttle 1979). In 1978 

 R. LaVal (personal communication) censused 27 

 Missouri caves that Myers (1964) had censused in 

 1964. Adult females and young had declined ap- 

 proximately 80%, and 16 caves occupied in 1964 

 had been abandoned. Estimates for the entire 

 State are not available, but the trend is downward 

 (R. LaVal personal communication), and is likely 

 to continue downward because of the bats' intole- 

 rance to disturbance, their concentration in a few 

 caves, and the possible effects of pesticide poison- 

 ing (R. LaVal personal communication). 



REPRODUCTION 



Copulation occurs in the fall; females store 

 sperm over the winter (Barbour and Davis 1969). 

 Young are bom in late May to early June and fly 

 by late June or mid-July (Tuttle 1976a). Sexual 

 maturity is reached at 2 years (Tuttle 1976a), al- 

 though LaVal et al. (1976) suggest that yearlings 

 breed. The females bear one young, and generally, 

 only females and young occupy the nursery cave 

 (Tuttle 1976b). Longevity is high— to 17 years— 

 but survival is only about 50% to maturity, so 

 that it takes a female about 5 years to produce 

 two surviving offspring (M. Tuttle personal com- 

 munication). 



MANAGEMENT AND CONSERVATION 



Until recently, there has been no manage- 

 ment or conservation effort. Most caves are in pri- 

 vate ownership (Tuttle 1975a). Several caves have 

 recently come under protection by Federal and 

 private owners (Harvey 1975, Tuttle 1979), but 

 improper gating of entrances, which results in de- 

 creased air flow, has caused the loss of several im- 

 portant colonies (Tuttle 1977, Tuttle and Steven- 

 son 1978). Predation at cave entrances has in- 

 creased with many types of gate. Bats slow down, 

 circle, or climb through the gates, increasing their 

 vulnerability to predators (Tuttle 1977). The U.S. 

 Army Corps of Engineers Meramec Park Lake and 

 Union Lake Projects in Missouri, which could 

 ehminate 50% of the gray bats in that area and 

 alter 60% of the foraging habitat, have been tem- 

 porarily restrained (LaVal et al. 1976). A Recovery 

 Team is being formed (M. Tuttle personal com- 

 munication). 



Tuttle (1979) makes the following recom- 

 mendations for conservation of this species: 

 (1) purchase severaJ major caves, which are es- 

 sential to the survival of the gray bat, and pro- 

 tect them by proper gating; (2) educate spelunkers 

 and persons interested in visiting bats in winter 



