4.3 Protocol: Presence/Not detected & Relative Abundance

4.3.1 Office procedures

• Review the introductory manual, Species Inventory Fundamentals (No. 1).
• Obtain suitable maps of the project area. Typically 1:50 000 are used, but a larger scale such as 1:20 000 may be useful.
• Based on the maps and other knowledge of the project area (previous reports, local resource specialists) identify strata which are of most interest. It may also be useful to identify specific study areas (i.e. sites) at which sampling will take place. Properly identified objectives will hasten this process.
• Consult Nagorsen and Brigham (1993) for species distribution information in order to compile a checklist of potential bats to be encountered in the study area. Discuss the bat community with local resource specialists along with amateur naturalists to further refine the expected list.

4.3.2 Sampling design

• Presence/not detected: Non-random. Choose study areas where bats are most likely to occur (Table 3).
• Relative abundance: Stratified random sampling. Stratify project area (e.g., different habitat types, stand age class), and establish study areas which allow you to sample randomly within each strata. Use the same type of detectors and capture devices throughout study.

4.3.3 Sampling effort

• Effectively, only one study area per night can be sampled (mist netting and manual ultrasonic detection) by a team of two to three people. Two person teams are adequate, if remote detector systems (e.g., ANABAT detectors) are available.
• When using remote detector systems, the number of detection stations sampled is limited only by the number of detectors.
• Each study area should be sampled more than once, and effort should be made to maximize replication. The confidence in the results will increase with repeated sampling of the same study area.
• For larger scale geographic areas, it is recommended that at least two circuits of the project area be made during the sampling season to account for seasonal variation in distribution or abundance.

4.3.4 Personnel

• All crew members should have up-to-date vaccinations against rabies and tetanus.
• The crew leader must be a biologist with experience mist-netting and identifying local bat species.
• The crew leader must have previous experience attaching light-tags before attempting this procedure.
• One crew member should be familiar with the use of bat detectors and should possess some ability to identify species by their calls using bat detectors.
• At least two crew members should be used for netting.
• All personnel should thoroughly review the Animal Capture and Handling manual before commencing with a RIC wildlife inventory survey that requires capture and/or handling.

4.3.5 Equipment

Capture:

• Mist nets, poles, and lines
• Harp trap(s)
• `Hands-free' headlamp (e.g., Petzel) with a spare batteries, for each field person
• Spotlight (optional)
• Leather or cotton gloves
• Cloth holding bags (for holding captured bats)
• Pesola spring scale (50 g capacity)
• Calipers
• Thermometer
• Identification key (Nagorsen and Brigham 1993; van Zyll de Jong 1985)
• Field note books
• Compass
• Camera with macro-lens and flash (to record voucher photos)

Ultrasonic Detection:

• Narrow-band
• Bat detectors with fully charged rechargeable batteries
• Spare rechargeable batteries
• Thermometer
• Microcassette recorder(s) for use with detectors(s)
• Talking clocks (remote detection only)
• Stands raising the detectors at least 1 m off the ground are recommended in forest habitats.
• During periods of questionable weather, the equipment (remote detection only) should be protected by water proof containers.
• Broad-band (e.g., ANABAT system)
• for remote detection: translucent plastic case (e.g., Rubbermaid container) with hole cut for microphone, bat detector, delay switch, timer (optional), tape recorder, 12 V battery, patch cords (to provide power from the battery to the various components)
• for manual sampling: bat detector, tape recorder or laptop (with delay switch and ZCAIM)

Light Tagging:

• Miniature light tags
• Surgical adhesive (e.g., Skinbond^®)
• Microcassette recorder(s) for voice notes

4.3.6 Preliminary fieldwork

• During the day, all personnel should visit the study area in order to check out access, locate suitable areas for nets (trap stations), set up equipment, and make sure detectors are working.
• Generate a habitat description of the study area (Ecosystem Field Form FS 882(1) HRE 96/4).
• Personnel should be aware of the various ecosystem distributions (i.e., biogeoclimatic zones), and the major (if any) land use practices in the project area.
• Landowners should be contacted for permission to sample on private land.

4.3.7 Field Procedures

Mist Netting

• At least two crew members are needed to be responsible for mist netting and harp trapping of bats.
• Up to five nets can be set up and managed by the two workers. A trap station (as specified in the accompanying data forms) may consist of more than one net.
• Environmental conditions (e.g., air temperature, cloud cover, wind, precipitation) at sunset should be recorded (see RIC standard data form).
• Net placement:
• Place nets near roosts, near openings to caves, mines or buildings, over streams, ponds, and small bodies of calm water, and along flyways such as riparian gaps, trails, along cliffs, cut lines, and tertiary roads (Kunz and Kurta 1988). Note that nets should not be set up directly in front of day roost openings because of potential disturbance to maternity colonies.
• A bat detector can be used to verify the presence of bat activity and thus ensure nets are set up at productive sites.
• Nets should be positioned to take advantage of topographic and vegetative features that could be used to 'channel' bats into the nets (Mills et al. 1996; e.g., Fig. 4).
• When setting nets across streams or trails, capture success is increased if the net is positioned beneath overhanging branches or canopy, which tend to channel bats into the net (Fig. 4). Often the spaces around nets can be closed by using loose, dead branches or rope. This also tends to induce bats to fly through the area occupied by the net.
• It is often easier to capture bats along commuting routes (such as flyways) rather than where they feed, because they may orient via spatial memory while commuting rather than by sensory perception (echolocation), and thus often fail to avoid a mist net (Mueller and Mueller 1979). In feeding areas, bats rely on their echolocation system, which increases their probability of detecting a mist net, and decreases netting success.
• In forested areas, nets can be set up at canopy height by using a system of guy ropes and pulleys (see Kunz and Kurta 1988). Presently, little is known about the vertical distribution of bats within the canopy (Thomas and West 1989; Bradshaw, 1996). Unless an effort is made to sample at different heights within the canopy, the presence of some species in a study area may go undetected.
• Nets should be set at several different heights to increase the chances of catching all species (see also Table 3).
• If netting on successive nights in the same area, the location of the nets should be changed each night to increase capture rate.
• Nets should not be opened before dusk, to prevent catching late flying birds. Occasionally owls and goatsuckers may be caught. Owls should be removed from the net by getting a firm hold of the feet (to protect the crew member); the beak is not a concern, although it looks like it should be.
• Nets must be monitored constantly from about a half hour before sunset to about 24:00 or 01:00 (or later at higher latitudes) depending on levels of bat activity. Capture success will typically decline as the night progresses.
• Each net should be checked at least every 10-15 minutes. Bats should be removed from a net from the same side as they entered, as determined by the position of the pocket relative to the shelf cord that separates each shelf (Figure 5; Kunz and Kurta 1988). Bats removed quickly from the net typically become less tangled and do less damage to the net. It may help to wear a loose fitting leather or a cotton glove on the left hand (for right-handed individuals). This gives a bat something to chew on other than your hand. There is no agreed upon method for removing a bat from a mist net. Freeing a wing or the tail first seems to work well. Some people find the use of a crochet hook helpful to remove a section of net from a bat's body.
• When a bat is caught, it should be removed immediately and placed in a cotton draw-stringed holding bag.
• Bats should be held until the netting session ends (to prevent recapturing the same individual) except for females that are in late stages of pregnancy or lactation. These should not be held for extended periods of time but should be released after processing at their site of capture.
• Bats should not be weighed until at least an hour after capture to allow food to clear the digestive tract.
• The species, sex, age, reproductive condition, mass, and forearm length of each bat should be recorded (see Section 3.4) as indicated on the accompanying dataforms. Note that for certain species which are difficult to key out (e.g., M. keenii and M. evotis), other morphometric measurements should be taken. These measurements include length of the: third and fifth metacarpals; tragus and ear; and tibia.
• Bats are released by letting them fly off the hand or placing them on a tree trunk to fly off on their own accord. If bats have become torpid, they will need to be rewarmed in the hand before release.
• If bats are to be held overnight for any reason, proper ventilation and water should be provided.

Harp Trapping

• Similar consideration should be given to the placement of harp traps, as was done for the placement of mist nets (see above).
• Harp traps do not require constant attention. However, they should be checked hourly when pregnant or lactating females are likely to be caught.
• Bats removed from harp traps should be treated in the same way as those taken from mist nets.
• Placing captured bats in cloth bags and hanging these near or on the harp trap or mist-net will often attract other bats to the area.

Euderma maculatum Detection

• The two crew members responsible for netting and trapping should also listen ad libitum for E. maculatum echolocation calls, starting about a half hour after sunset.
• At roost sites (steep cliffs) the number of individuals can be directly counted by listening to echolocation signals as the bats emerge after dusk.
• Euderma maculatum emerge quite late and listening at roost sites should continue for at least an hour after sunset. Listening should continue all night at potential foraging sites.
• It is not advisable to use ultrasonic detectors while listening for spotted bats as the static `roar' of the detectors often reduces the observer's ability to hear E. maculatum calls.

Ultrasonic Detection

• During the day, battery levels of the detector components (e.g., detectors, voice activated tape recorders, talking clocks, etc.) should be checked. If possible, bat detectors should be calibrated using a pure tone (Thomas and West 1984).
• One crew member should be designated for set up and monitoring the bat detection equipment and data collection.
• For remote detection monitoring, bat detector systems (e.g., narrow-band detectors with talking clocks and voice activated tape recorder, or broad-band ANABAT system) are set up in the habitat of choice. The location of the detection stations may be similar to those chosen for mist netting.
• Detectors:
• Each study area should have at least two tunable detectors set at 25 kHz and 40 kHz (also 30 kHz if possible). Each detector has its own talking clock and recorder. The voice activated tape recorders should be calibrated so they are set off by the talking clock and bat recorder, but not by background noise (e.g., wind, rain, insects, frogs). Detector set-ups can be collected in the morning. The tape should be labeled and tested. If habitats are being compared (i.e., relative abundance), it is imperative to have equipment set up in both strata.
• For manual detecting with tunable narrow band detectors, the crew member should tune the detector to and monitor at frequencies of 20 kHz, 30 kHz, and 40 kHz. Each frequency should be monitored for five minute intervals, and any species heard should be noted, including the number of bat passes and feeding buzzes heard. After five minutes, the detector should be tuned to the next frequency.
• Detectors:
• With the ANABAT system, the ZCAIM, and delay switch can be used with a portable computer. This increases the quality of the recordings, as the data do not need to be transferred from an analog format, and are recorded directly to a digital format. As the ANABAT records calls at all frequencies and records time, the set-up is less complicated. Tapes are analyzed to determine the number of bat passes, minutes of bat activity by species, and compared with reference calls to identify species or species groups.

Light Tagging

• After bats are captured (see above), light tags are activated by breaking the inner capsule in miniature light sticks.
• A small amount of Skinbond^® surgical adhesive is applied to the activated light tags, then attached to the back (for low flying bats, e.g., M. lucifugus) or abdomen (for higher flying species, e.g., E. fuscus) of the bat.
• Once the tag is affixed, the bat should then be released in an area of low bat activity and the echolocation calls recorded as the bat departs. Forest clearings make good release sites as the bat will tend to circle several times before flying out of range (D. Thomas, Personal communication).
• For behavioural observations, numerous observers (as many as possible) should be stationed at vantage points in the study area where the light tagged bats may be flying. Voice records of bat observations can be collected on tape recorders.
• For collecting reference calls, bat detector systems can record echolocation calls once the tagged bat is released.

4.3.8 Data analysis

• For each study area, the number of species captured or detected should be tabulated.
• For each species, sex, and reproductive class (if known) the following should be calculated:
• Number of bats caught per net-night or per hour (a net-night is equivalent to one six metre length of net set up for one night).
• Number of bats caught per night or hour of harp trapping.
• Number of bat passes/unit time.
• Number of feeding buzzes/unit time.