DOI: 10.25338/b8kh19
title: Data from: Seasonal phenology of the little brown bat (Myotis lucifugus) at 60°N

description: To investigate the impact of short summers and long summer solar periods
 at high latitudes on the behavior of a nocturnal, hibernating mammal, we
 recorded the phenology of Myotis lucifugus (little brown myotis) at 60oN
 in the Northwest Territories (NWT), Canada. In particular we assessed the
 timing of spring emergence from, and autumn entry into hibernation,
 reproduction, and seasonal mass fluctuations. We used a combination of
 acoustic monitoring and capture surveys at two hibernacula and two
 maternity roosts during 2011 and 2012. Myotis spp. were active at the
 hibernacula from late April to late September/early October, suggesting
 that the ‘active’ season length is similar to that of populations farther
 south. At maternity colonies, we detected M. lucifugus activity from early
 May to early October, with peaks during mid-July in both years. Lactation,
 fledging, and weaning all occurred later in the NWT than at more southern
 locations, and reproductive rates were significantly lower than rates
 observed further south. Average mass of individuals fluctuated throughout
 the season, with an initial decline immediately following emergence from
 hibernation likely reflecting increased energy expenditure due to flight
 and decreased use of torpor, coupled with relatively low prey intake due
 to low prey abundance associated with cool temperatures. Females did not
 appear to have lower pre-hibernation masses than those in more southern
 populations, suggesting that despite the cool spring and autumn
 temperatures, and short summer nights, bats are able to obtain enough
 energy for reproduction and mass accumulation for hibernation. However,
 the lower reproductive rates may indicate that there are limitations to
 life at the northern limits of the species’ range.
description: <strong>Capture data</strong> - We used mist nets (Avinet Inc. Dryden, New
 York), to capture bats adjacent to the two <em>Myotis
 lucifugus</em> maternity colonies (Thebacha and Lady Evelyn Falls),
 and various foraging sites around the South Slave region, during 2011 (35
 nights; May - Sep) and 2012 (23 nights; Jun - Sep). At maternity colonies,
 we captured bats during emergence, before they had an opportunity to feed,
 and at all sites we held bats in a cloth bag for ≥ 0.5 h to allow
 defecation prior to weighing. A small number of bats were caught
 post-foraging; these records have been marked with an asterix in the
 'massinacuracy' column of the dataset and were omitted from the
 mass-related analysis. We identified individuals to species, sex, age
 (adult or juvenile) and reproductive condition, weighed them with a
 portable balance, measured forearm with calipers, fitted them with a
 unique band (2.9 mm; Porzana Ltd., East Sussex, United
 Kingdom) for future identification, and released them at their point of
 capture. We classified adult females into three categories: 1) Pregnant:
 swollen abdomen, detection of fetus via palpation of abdomen, non-enlarged
 nipples; 2) Lactating: enlarged, calloused nipples, milk expressed with
 gentle massage of mammary glands; 3) Post lactating: enlarged keratinized
 nipples with no milk expression (Racey, 2009). Females captured prior to 1
 June were not included when calculating reproductive rates as
 non-reproductive and early pregnancy females were indistinguishable by
 external examination. All volant juveniles were identified by evenly
 tapered phalangeal-metacarpal joints and un-fused epiphyseal plates
 observed by back-illuminating the wing (Brunet-Rossinni and Wilkinson,
 2009). During November 2011, after hibernation was well underway, we
 entered both hibernacula and recorded sex, mass and forearm length for 45
 bats captured from the cave walls (Walk-in cave: <em>n</em> =
 5; South Slave hibernaculum: <em>n</em> = 40). All captures
 followed American Society of Mammalogists guidelines (Sikes et al., 2016)
 and were compliant with the University of Calgary Animal Care and Use
 Committee protocols (Animal Care Certificate
 BI09R-01). <strong>Acoustic
 surveys</strong> – We recorded echolocation calls
 using AnaBat II ultrasonic detectors with CF-ZCAIMs set to a division
 ratio of 16 (Titley Electronics, Ballina, Australia). Detectors were
 placed at five sites including two hibernacula (Walk-in Cave and South
 Slave Hibernacula) and two beaver ponds (WBBP and NTBP) within 3 km of
 each hibernaculum, and at the Thebacha maternity colony. At Walk-in Cave,
 we placed the detector in a weatherproof box, 3 m from the entrance with
 the microphone pointed away from the entrance to prevent recording bats
 flying within the cave. Two detectors were installed in weatherproof boxes
 at the South Slave hibernaculum by the Government of the Northwest
 Territories, approximately 10 m from the cave entrance with the
 microphones positioned towards the cave entrance, but the restricted cave
 opening prevented recording of bat activity inside the cave. At the
 Thebacha maternity colony, we mounted the detector directly along a bat
 flight path outside the main building used by the colony, 3 m off the
 ground and 5 m from the bat exit. <strong>Acoustic
 analysis</strong> -
 We reviewed all AnaBat files using AnaLookW version 3.2.15. We used a
 filter to extract <em>Myotis</em> spp. calls, identified by a
 minimum frequency ≥ 30 kHz , and counted files recorded per night. Bats
 with lower-frequency echolocation calls (primarily <em>E.
 fuscus</em>) were omitted from the data. Call characteristics of
 <em>M. lucifugus</em> and <em>M.
 septentrionalis</em> overlap (Fenton and Bell 1981), often making
 them indistinguishable with AnaBat II detectors, therefore, we did not
 attempt to remove <em>M. septentrionalis</em> calls from the
 data. The composition of Myotis captures (via mist-netting) at these sites
 averaged 86% <em>M. lucifugus</em> and 14% <em>M.
 septentrionali</em>s (n = 1118; Reimer and Barclay, DRYAD dataset),
 therefore, we assume that the <em>Myotis </em>echolocation
 passes in our data were largely representative of <em>M.
 lucifugus</em> activity.
description: # **Data from: Seasonal phenology of the little brown bat (*Myotis
 lucifugus*) at 60°N** Two simple
 comma separated (csv) files associated with the manuscript "Seasonal
 phenology of the little brown bat (*Myotis lucifugus*) at 60°N" by
 Jesika P. Reimer and Robert M. R. Barclay, accepted by Ecosphere. ##
 **Description of the data and file structure** **Dataset 1:
 NWTMyotisCaptureRecords.xls** Morphometric measurements and reproductive
 status for *Myotis lucifugus* and *Myotis septentrionalis* captured during
 summer surveys at maternity colonies, hibernacula, and foraging sites in
 the Northwest Territories, Canada during summer 2011 and 2012. These data
 were used to calculate maternity colony reproductive rates, the timing of
 parturition and juvenile fledging, and to assess changes in *Myotis
 lucifugus* mass throughout the season. Empty cells and NA: cells were left
 empty when data were not available/not recorded. Variables: Night_date:
 the date the survey was started and includes captures after midnight on
 the next calendar date (e.g. captures at 23:55 on 2 June and 01:00 on 3
 June both have a night_date value of 2 June). Latitude: Latitude of
 capture survey location, truncated to 1-2 decimal places to preserve
 privacy of restricted locations. Longitude: Longitude of capture survey
 location, truncated to 1-2 decimal places to preserve privacy of
 restricted locations. Region: A one-word descriptor that groups survey
 sites into broader-scale regions. Site: A site-specific text descriptor
 that identifies each unique survey site. BandID: The unique ID code
 printed on the Porzana arm band affixed to the bat. Can be used as a
 unique identifier for individual bats. Species: Standardized species name
 (genus species) Sex: Sex of individual; ‘Female’ or ‘Male’ Ageclass:
 General age of individual group into ‘Adult’ – fused epiphesial joints,
 ‘Juvenile’ – young of the year identified by un-fused epiphesial joints,
 ‘UNK’ – unknown age class. Massg: Mass of individual measured in grams.
 Massinacuracy: Asterix indicates that the bat was captured post-foraging
 and was not held a sufficient amount of time to ensure an accurate weight.
 Do not use these data points for mass-related analysis. Forearmlengthmm:
 Individual forearm length measured in millimetres. Earlengthmm: Individual
 ear length measured in millimetres. Reproductivestatus: Individual
 reproductive status; ‘JUV’ – juvenile, ‘LAC’ – lactating, ‘NOP’ – not
 obviously pregnant (may indicate non-reproductive female, or a female
 captured early in the season before pregnancy is detectable with manual
 palpation), ‘POST’ – post-lactating, ‘PREG’ – pregnant. Comments: Comments
 regarding individual noted during capture. Capturetime: The time at which
 the bat was removed from the capture net. Releasetime: The time at which
 the bat was released after processing. **Dataset 2:
 NWTMyotisAcousticRecords.xls** Nightly summary of acoustic recordings for
 *Myotis* species during acoustic surveys at maternity colonies,
 hibernacula and foraging sites in the Northwest Territories, Canada during
 summer 2011 and 2012. These data were used to describe seasonal activity
 of *Myotis* in the area. Empty cells: cells were left empty when the
 acoustic detector was not active. Variables: Site: A site-specific text
 descriptor that identifies each unique survey site. Latitude: Latitude of
 capture survey location, truncated to 1-2 decimal places to preserve
 privacy of restricted locations. Longitude: Longitude of capture survey
 location, truncated to 1-2 decimal places to preserve privacy of
 restricted locations. Night_date: the date the survey was started and
 includes captures after midnight on the next calendar date (e.g. captures
 at 23:55 on 2 June and 01:00 on 3 June both have a night_date value of 2
 June). Myotis: Total acoustic files identified as a *Myotis* species
 recorded on a given night; this classification is used at hibernacula and
 foraging sites where both *M. lucifugus* and *M. septentrionalis* have
 been observed. Detector Active: Indicator of whether a detector was
 functioning correctly during the survey period (derived from the detector
 log files); ‘Yes’ – detector was functioning, ‘No’ – detector was not
 functioning (e.g. dead batteries). Site type: Classification of site type;
 ‘Foraging site’, ‘Hibernaculum’, ‘Maternity colony’