Date(s): May 29; June 3, 4, 10, 17, 23, 27; and July 14, 2008

Location: Adair County, Oklahoma

Participants: Richard Stark, Glen Hensley, Anita Barstow - Oklahoma Ecological Services Field Office; Steve Hensley - Ozark Plateau National Wildlife Refuge; and Bill Puckette –Contract Biologist

Executive summary:

Staff from the Oklahoma Ecological Services Field Office, the Ozark Plateau National Wildlife Refuge, and Bill Puckette, contract biologist, conducted the annual census of most of the known maternity colonies of the federally-listed endangered Ozark big-eared bat during late-May, June, and July 2008.  The censuses primarily consist of conducting exit counts of the adult female bats as they emerge from the maternity cave at night to forage using night vision equipment, infrared lamps, and a camcorder with nightshot. 

Richard Stark and Bill Puckette monitored cave AD-125 on May 29th, and counted 133 Ozark big-eared bats (OBEBs).  Bill Puckette conducted an exit count at cave WA-5202 on June 2nd, but the colony could not be located.  This may be due to bats utilizing caves of which we currently are not aware.  Bill Puckette conducted an exit count at Cave AD-13 (Coon Mountain Colony) on June 3^rd, and counted 67 OBEBs.  Steve Hensley and Bill Puckette monitored the CW-21BT1 cave complex on June 4th.  This colony was discovered for the first time during the summer of 2006.  Only OBEB bat was counted from the site indicating that the maternity colony likely is using an unknown site.  More field work is needed at this cave complex to gain a better understanding of OBEB use of the area.  Richard Stark and Steve Hensley monitored cave AD-18 and Bill Puckette monitored cave AD-17 on June 10^th.  Eighteen OBEBs bats were counted from AD-18, while 186 were counted from AD-17.  Richard Stark, Steve Hensley, Bill Puckette, Glen Hensley, and Anita Barstow (OKESFO STEP and SCEP students, respectively) monitored cave AD-10 on June 17^th, and counted 289 OBEBs.  An exit count was conducted at cave AD-14 on June 23^rd.  The OBEB is known to utilize this cave during the summer, but the nature of use is not well understood at this time.  It is believed that the maternity colony that rears their young in cave AD-125 also uses cave AD-14.  It also is possible that cave AD-14 is used by a separate maternity colony.  However, cave AD-14 is difficult to monitor because it has eleven entrances and over nine miles of passage.  Emerging bats were counted at four entrances by Richard Stark, Steve Hensley, Glen Hensley, and Bill Puckette.  The entrance from which the largest number of emerging bats was observed also was filmed using infrared lights and Sony Nightshot.  The footage will be reviewed in slow motion to help gain a better understanding of summer use of this cave by the OBEBs.  Cave CZ-19 was monitored by Richard Stark and Steve Hensley on June 27, 2008, to look for evidence of summer use by OBEBs.  This cave is known to be used by large numbers of OBEBs during the fall.  The emergence of bats from this cave also was filmed for later review.   The maternity colony at the CW29BT cave complex was monitored on July 14, 2008.   Due to the difficulty in conducting an exit count at this cave complex, a photograph of the roosting colony was taken from which a colony size estimate will be made.  

The numbers of bats counted at cave AD-125 was similar to last year’s count and was high as compared to other recent years (35 bats in 2005 and 36 bats in 2006).  The numbers from most of the other colonies, except WA-5202, were consistent with counts in recent years.  Evidence of recent vandalism was observed at one OBEB cave, cave CZ-19.  The cave was previously gated to help prevent human disturbance to roosting bats.  The cave gate had been breached.  Evidence of recent unauthorized entry was present inside the cave in the form of recent soda and beer cans.  The cave gate has since been repaired using funds from an ongoing cave management project funded by traditional ESA section 6 funds.  We anticipate conducting exit counts at a subset of the maternity caves during August when the young-of-the year will be capable of flight to gain data on recruitment.

FWS programs involved: Ecological Services and Refuges