Surveying For & Squirrels in Northern England: Methodologies 1 Introduction Squirrels Northern England will establish a program of standardised red and grey squirrel monitoring at selected sites across Northern England, to start in 2012. Each monitoring point is located within a defined 2km tetrad. The network of tetrads (>250 sites) will be surveyed bi-annually in the spring and autumn using either baited visual transects, trail cameras or observed feeding stations. The collection of data using these methods will contribute towards a detailed understanding of red and grey distribution over time across the project area, and will be used to help gauge the successes or otherwise of red squirrel conservation activity. 2 Baited visual transects Building on published recommendations (Gurnell et al 2009 & 2011), the methodology detailed here will be used to survey for squirrels using baited visual transects. Surveyors will need the following equipment: A detailed map of the woodland Measuring device, for example tape measure or measuring wheel. Ideally a GPS should be used to pinpoint the transect Hair tubes (300m length, 65mm square ended or round diameter) Sticky hook & loop pads (at least 20mm x 20mm) Wire or straps to secure tube to branch Bait (squirrel mix containing approximately 45% sunflower, 45% maize and 10% peanuts) Wooden ground pegs to mark out route (make sure they are visible! For example spray-paint the pegs) if not using a GPS Self-seal bags for collecting sticky pads/hair samples & waxed paper to protect the hairs for storage RSNE Visual survey sheets for recording sightings Binoculars The activity timeline for surveys should be as follows: Carry out ground truthing exercise to establish whether the woodland is suitable particularly with regards to terrain. It needs to be fairly easily accessible for surveyors. Ensure that the potential transect route falls entirely within a tetrad. Look to establish a route through suitable habitat for seeing squirrels, in particular open woodlands containing Scots pine, larch or broadleaved species. Crucially, make sure access permission is granted and does not interfere with other land use. Each transect should be 1000m in length and will have three hair tubes placed separately along the length. The tubes contain double sided tape that catches squirrel hair as an animal investigates the tube. If hair is found and yet no sightings of animals are made when transects are walked, the tubes will provide a means of demonstrating a false negative from
the transect line. The transects and hair tubes will provide data on presence/absence which can be used in assessing changes in squirrel presence across the RSNE study area. Mark out the transect using a measuring device, marking each 50m with a ground peg if not using a GPS unit. A 50m tape can be used to establish the transect line, but this is best done with two people otherwise the tape inevitably gets snagged, or the thankless task of winding the tape in and out can become a little trying. Each point needs to be marked to ensure that the exact methodology can be replicated bi-annually, and over a number of years. The marking of 50m points is also important as transects will be baited prior to walking in order to draw animals in and make them more visible. Knowing the walk intervals allows bait to be spread evenly. Transects can follow footpaths, and consequently there may be locations where markers will be removed by third parties. If such a well-defined route is used, the start and finish points should clearly recorded (perhaps with reference to a particular distinctive tree, fence line, wall or other feature that can clearly be distinguished). The ease with which a transect line can be completely or partially forgotten should not be underestimated especially when they are going to be revisited after six month intervals. Making notes is essential particularly with reference to start point, finish point and the location of hair tubes. Transects do not necessarily need to follow continuous lines within a woodland. If open ground is present, surveyors can disregard this area, and continue to establish the 1km route in an adjacent block. The following figure illustrates this: Follow established paths where possible for ease of location and access. It is not important that transect lines are straight, although you should try to avoid doubling back wherever possible, as this in effect reduces the area in which squirrels can be detected due to overlap. At three points along the transect set up a hair tube close to the transect line. By placing these at bait points, it will make it easier to find the tubes on later visits. Add a piece of tape to a prominent branch close to the path to aid detection of each hair tube location. Look for signs of squirrels, for example dreys or active feeding areas (for example stripped cones on tree stumps) and place hair tube close by. Once the transect line is marked out, then the pre-baiting can commence. This should be carried out as follows:
Bait the transect every 50m with a mixture of maize, sunflower seed and peanuts. Three or four handfuls of bait (around a coffee mug full) should be widely scattered at each 50m point (this could also be done on Day 1, the same day that the transect was established) Bait the three hair tubes with the mix during the same visit. Attach the sticky pads, one at each end of the tube about 3cm in from the end, and attach the reverse sticky pads to these (i.e. hook pad to a loop pad or vice versa). Retain the sticky pad backing paper to re-cover them when collecting the tubes 2 weeks later. Also add a few hazelnuts to the tube to attract squirrels, and scatter bait around the base of the tree. Walk and bait the visual transect again on Day 4 or 5 as above. Hair tubes can be re-baited. Following the period of pre-bait, the surveys can take place. These should be done over a period of a week, with surveys done on three separate days, as follows: Walk the transect one week (Day 7 or 8) after the first pre-baiting took place Walks should take place in the morning (aim to start around 7 or 8am), where possible when the weather is fine. Try to avoid surveying on days with heavy rain or strong winds, as detection of squirrels is more difficult, and they may be less active. The transect should be walked slowly, so that it takes around five minutes to walk 100m. It is best to stop frequently, taking time to scan the woodland above and around. Try to listen carefully for movement in the canopy. Each sighting of a squirrel should be noted so that the total number of sightings of red and grey squirrels is recorded. It is inevitable that some sightings will be no more than a fleeting glance of an animal when it may be impossible to say 100% certainty what species it was, in which case record as unsure (of the species). Walk the transect on a further two occasions within the period of a week. This must take place regardless of whether red, grey or both species were recorded on the first walk. This ensures the methodology remains standardised over time, and also will allow for further analysis of numbers seen over time. Fill in all details on the RSNE Baited Visual Transect Survey Recording Form. After completing the final walk, collect the pads from the hair tubes, protect them by covering with waxed paper (the sticky pad backing paper), and label them and store for analysis. Timetable summary It is recommended that all project monitoring takes place within an 8-week period in the spring (March and April) and autumn months (October-November) as follows: Day 1: Bait and set out the line transect and fix hair tubes. Day 4/5: Re-bait the line. Day 7/8 : First Walk the transect recording each squirrel sighting. Day 8-14: Repeat transect on two more occasions. Last Walk: The hair tubes should be removed and returned to the project for examination of hair.
IF POSSIBLE PLEASE TRANSFER SURVEY RESULTS TO THE ELECTRONIC RSNE MONITORING SPREADSHEET AND RETURN THIS VIA EMAIL (records@rsne.org.uk) Survey sheets and equipment (including hair samples) should be returned to the appropriate RSNE office at either of the following: RSNE Unit 10 Stocksfield Hall Stocksfield Northumberland NE43 7TN RSNE c/o Cumbria Wildlife Trust Gosling Sike Farm Houghton Road Houghton Carlisle Cumbria CA3 0LD
Baited visual transect survey recording form Site name: Transect Transect number: length: Woodland type: (i.e. Mixed (M), Broadleaf (B) Conifer (C)) Surveyor s name: Date first baited: Date second bait: Six fig grid reference for start of transect (10 fig if using GPS): First walk Date walked: Time started: Weather: Squirrels seen Number squirrels seen Comments (e.g. alive, adult, healthy) Second walk Date walked: Time Started: Weather: Squirrels seen Number squirrels seen Comments (e.g. alive, adult, healthy) Third Walk Date walked: Time started: Weather: Squirrels seen Number squirrels seen Comments (e.g. alive, adult, healthy) Hair tube ID Date first erected & baited Hair tubes Six fig grid reference Hairs present (Y/N) Confirm or (R/G or BOTH) IF POSSIBLE PLEASE TRANSFER SURVEY RESULTS TO THE ELECTRONIC RSNE MONITORING SPREADSHEET AND RETURN THIS VIA EMAIL (records@rsne.org.uk) Survey sheets and equipment (including hair samples) should be returned to the appropriate RSNE office at either of the following: RSNE, Unit 10, Stocksfield Hall, Stocksfield, Northumberland, NE43 7TN RSNE, c/o Cumbria Wildlife Trust, Gosling Sike Farm, Houghton Road, Houghton, Carlisle, Cumbria, CA3 0LD
3 Methodology for observed feeding stations Surveyors will need the following equipment: Flip-top lid feeder box Disinfectant (Trigene or Virkon S) Sticky hook & loop pads (at least 20mm x 20mm) Bait (squirrel mix containing approximately 45% sunflower, 45% maize and 10% peanuts) Self-seal bags for collecting blocks/hair samples (with waxed paper for protecting hairs) RSNE fixed monitoring point recording form The number of monitoring points should be one point per tetrad. For example, feeding stations in neighbouring gardens within the same tetrad do not count as separate data points. In order to ensure standardised replication of methodology, over time and over geographical areas, it is recommended that only one sample point should be selected per tetrad. It is much harder to ensure survey effort is repeated if, for example, people in separate gardens chose to survey. Sticky pads should also be used, attached on the underside of each feeding box lid. This will provide additional back-up in a situation where no squirrels are observed during the survey windows. Any hairs left can then be analysed to confirm species present (red or grey). It should also be clarified that in some cases the monitoring point may be several feeders, for example in a garden where multiple feeding boxes are in use. In such cases, concentrate survey effort on one feeder, but do not discount data from other feeders. Together, multiple feeders only equate to one sample point. In terms of the monitoring window, there is a standardised time period during which squirrels can be observed. This ensures that survey effort can be repeatable over time and space, and that effort is closely replicated between the different survey methods (visual baited transects, feeding stations and fixed cameras). All methods involve a pre-bait period, and involve monitoring on three separate days. The table below summarises the level of effort for each technique: Method Additional method Survey period Monitoring window within survey period (when data is recorded) Baited visual transect Feeding station Fixed camera (with feeder box) 3 x hair tubes 10-14 days 3 walks, each approximately 1.5 hours, completed within a 7 day period. Begin walk between 7-8am 2 x sticky pads (placed on underside of feeder 10-14 days 3 observation surveys, each for 1.5 hours, within a 7 day period. Begin observation between 7-8am to collect hairs) 2x x sticky pads 14 days 3 data collection days, each for 3 hours. Collect data from 7-10am.
Note that the data collection or observer window for fixed cameras is twice the length of that for the other two methods. It was decided that this is a reasonable length of time, as the visual field of view is less for this method, so an extended time window compensates for this. The activity timeline for surveys should be as follows: On Day 1, erect feeding box in a suitable position where it can be easily monitored, positioning it on a tree at around eye-height to allow for easy feeder filling and cleaning. Fill the feeder with suitable squirrel mix. Record the exact location of the feeder. A 6 figure grid reference will suffice, or record using a GPS. This ensures the survey can be replicated over time. Attach two sticky pads to the under-side of the feeder lid as a back-up in case no squirrels are observed during the survey window. Retain the sticky pad backing paper to re-cover them when putting in sample bags later. The pads will be present throughout the duration (approximately 10 to 14 days from first set-up to the end of the third survey) therefore should be able to detect the presence of squirrels where they have not been observed. Pre-bait the feeder again on Day 4 or 5. Begin Survey 1 on Day 7 or 8. The survey should take place in the morning, starting at around 7-8am, and will involve continuous observation of the feeding station. The survey period should last for 1.5 hours during which all observations of squirrels should be recorded on the standard fixed monitoring point recording form. Try to differentiate between different squirrels looking for distinctive features, for example different tail colours or patterns. This will be important, as it may result in the recording of, for example, two individuals, as opposed to 10 animals (the same two over multiple visits). At the end of the third feeding station survey, collect any hair samples by removing the pads and storing in a self-seal polythene bag. Protect the hairs by covering with waxed paper (the hook and loop backing paper). Complete the recording form and return to RSNE. Time table summary for feeding stations Day 1: Set up feeder and attach 2 sticky pads/double-sided sticky tape to the underside of the feeder lid. Fill feeder with squirrel mix. Day 4/5: Disinfect then re-bait the feeder. Day 7/8 : Carry out Survey 1, observing squirrels and recording any sightings, beginning between 7-8am. Day 8-14: Repeat the observational survey on two further occasions (Survey 2 & 3). On completion of all three, remove any hair samples, label and store. Return samples and survey forms to RSNE for further analysis.
IF POSSIBLE PLEASE TRANSFER SURVEY RESULTS TO THE ELECTRONIC RSNE MONITORING SPREADSHEET AND RETURN THIS VIA EMAIL (records@rsne.org.uk) Survey sheets and equipment (including hair samples) should be returned to the appropriate RSNE office at either of the following: RSNE Unit 10 Stocksfield Hall Stocksfield Northumberland NE43 7TN RSNE c/o Cumbria Wildlife Trust Gosling Sike Farm Houghton Road Houghton Carlisle Cumbria CA3 0LD
Fixed monitoring point: Observed feeding station recording form Site name: Habitat type (G=Garden B=Broadleaved woodland C=Coniferous M=Mixed): Surveyor s name: Six fig grid reference (10 fig if using GPS): Survey 1 Date: Time Started: Weather: Squirrels seen No. of separate visits to feeder Comments (e.g. alive, adult, healthy) No of different squirrels (if easily recognisable) Survey 2 Date: Time Started: Weather: Squirrels seen No. of separate visits to feeder Comments (e.g. alive, adult, healthy) No of different squirrels (if easily recognisable) Survey 3 Date: Time Started: Weather: Squirrels seen No. of separate visits to feeder Comments (e.g. alive, adult, healthy) No of different squirrels (if easily recognisable) Hair samples present (Y/N) Confirm, or Both (R/G/B) IF POSSIBLE PLEASE TRANSFER SURVEY RESULTS TO THE ELECTRONIC RSNE MONITORING SPREADSHEET AND RETURN THIS VIA EMAIL (records@rsne.org.uk) Survey sheets and equipment (including hair samples) should be returned to the appropriate RSNE office at either of the following: RSNE, Unit 10, Stocksfield Hall, Stocksfield, Northumberland, NE43 7TN RSNE, c/o Cumbria Wildlife Trust, Gosling Sike Farm, Houghton Road, Houghton, Carlisle, Cumbria, CA3 0LD
4 Methodology for baited trail cameras Surveyors will need the following equipment: A detailed map of the woodland Flip-top lid feeder box and motion-activated trail camera Disinfectant (Trigene or Virkon S) Sticky hook & loop pads (at least 20mm x 20mm) Bait (squirrel mix containing approximately 45% sunflower, 45% maize and 10% peanuts) Self-seal bags for collecting blocks/hair samples (with waxed paper for protecting hairs) RSNE fixed monitoring point recording form In order to ensure standardised replication of methodology, over time and over geographical areas, it is recommended that only one sample point should be used. Fixed cameras should be established at a density of one camera per tetrad. Sticky pads should also be used, attached on the underside of each feeding box lid. This will provide additional back-up in a situation where no squirrels are observed during the survey windows. Any hairs left can then be analysed to confirm species present (red or grey). Also, in the eventuality of camera malfunction, there is a back-up surveying tool in place. In terms of monitoring windows, there is a standardised time period during which squirrels should be observed. This ensures that survey effort can be repeatable over time and space, and that effort is closely replicated between the different survey methods (visual baited transects, feeding stations and fixed cameras). All methods involve a pre-bait period, and involve monitoring on three separate days. The table below summarises the level of effort for each technique: Method Additional method Survey period Monitoring window within survey period (when data is recorded) Baited visual transect Feeding station Fixed camera (with feeder box) 3 x hair tubes 10-14 days 3 walks, each approximately 1.5 hours, completed within a 7 day period. Begin walk between 7-8am 2 x sticky pads (placed on underside of feeder 10-14 days 3 observation surveys, each for 1.5 hours, within a 7 day period. Begin observation between 7-8am to collect hairs) 2 x sticky pads 14 days 3 data collection days, each for 3 hours. Collect data from 7-10am.
Note that the data collection or observer window for fixed cameras is twice the length of that for the other two methods. It was decided that this is a reasonable length of time, as the visual field of view is less for this method, so an extended time window compensates for this. In terms of choosing the survey days for fixed cameras it is recommended that footage from the first three days following the pre-bait period is used. In this way, data from Day 7, 8 and 9 should be used. An exception to this rule could be where footage reveals excessive wind and rain. Extreme weather is likely to affect squirrel activity, and therefore it would be reasonable to exclude data from such a day, and move on to the next day. This flexibility replicates the ability of a human observer (as in baited visual transects and feeding station monitoring) to make a choice on whether to survey depending on environmental factors. The activity timeline for surveys should be as follows: Once a location has been identified, ensure access permission has been granted, taking into account timings for surveys (bi-annually in spring and autumn). Make sure that access can be assured in the long term, and that this does not clash with other events, in particular local shoots in the autumn. On Day 1, erect feeding box in a suitable position on a tree at around eye-height to allow for easy feeder filling and cleaning. Fill the feeder with suitable squirrel mix. Attach camera in an appropriate position away from the edge of the woodland, or away from public footpaths to limit the chances of the camera being interfered with. Focus the camera on the feeding box at a distance of around 10-15 ft. This will establish a modest sized window frame, without being too wide as to pick up too much movement within the surrounding environment (thus generating masses of data). However it should be sufficient to pick up footage of squirrels foraging on the ground close to the feeding station. Record the exact location of the feeder. A 6 figure grid reference will suffice, or record using a GPS. This ensures the survey can be replicated over time. Attach two sticky pads to the under-side of the feeder lid as a back-up in case no squirrels are observed during the survey window. Retain the sticky pad backing paper to re-cover them when putting in sample bags later. The pads will be present throughout the duration (approximately 10 to 14 days from first set-up to the end of the third survey) therefore may be able to detect the presence of squirrels where they have not been observed (and particularly if the camera malfunctions). Pre-bait the feeder again on Day 4 or 5 if it is possible to do so. In extremely remote forest locations, it is not essential that this second pre-bait takes place. The observation window should be a 3 hour period on 3 consecutive days following the initial pre-bait and feeder establishment period (7 days) (not continuous data for the period that the camera is in position and recording). As hair samples will be collected as a back-up, analysis of all images generated during the 2 weeks is not necessary. By the end of week 2, remove the fixed camera and collect any hair samples by removing the pads and storing in a self-seal polythene bag. Protect the hairs by covering with waxed paper (the hook and loop backing paper). Complete the recording form once the footage
has been reviewed, or return the partially completed form along with the camera and hair samples to RSNE for further analysis. Time table summary for fixed cameras Day 1: Set up feeder box and bait. Set up camera at a distance of approximately 10-15 ft. Also attach sticky pads to underside of feeder box lid. Day 4/5: Re-bait feeder if possible (not expected in remote woodland locations) Day 14 Return to site and remove camera. Remove any hair samples from the box, label and store appropriately. Return equipment to RSNE for further analysis OR download footage to PC and analyse images (if this has been agreed with RSNE). IF POSSIBLE PLEASE TRANSFER SURVEY RESULTS TO THE ELECTRONIC RSNE MONITORING SPREADSHEET AND RETURN THIS VIA EMAIL (records@rsne.org.uk) Survey sheets and equipment (including hair samples) should be returned to the appropriate RSNE office at either of the following: RSNE Unit 10 Stocksfield Hall Stocksfield Northumberland NE43 7TN RSNE c/o Cumbria Wildlife Trust Gosling Sike Farm Houghton Road Houghton Carlisle Cumbria CA3 0LD
Fixed monitoring point: Baited trail camera recording form Site name: Surveyor s name: Date camera & feeder installed: Date of 2nd pre-bait (if applicable): Six fig grid reference (10 fig if using GPS): Habitat type (G=Garden B=Broadleaved woodland C=Coniferous M=Mixed): First observation window Date: Start time (3 hour period) Weather: Squirrels seen No. of separate squirrel images No of different squirrels (if easily recognisable) Comments Second observation window Date: Start time (3 hour period) Weather: Squirrels seen No. of separate squirrel images No of different squirrels (if easily recognisable) Comments Third observation window Date: Start time (3 hour period) Weather: Squirrels seen No. of separate squirrel images No of different squirrels (if easily recognisable) Comments Hair samples present (Y/N) Confirm, or Both (R/G/B) IF POSSIBLE PLEASE TRANSFER SURVEY RESULTS TO THE ELECTRONIC RSNE MONITORING SPREADSHEET AND RETURN THIS VIA EMAIL (records@rsne.org.uk) Survey sheets and equipment (including hair samples) should be returned to the appropriate RSNE office at either of the following: RSNE, Unit 10, Stocksfield Hall, Stocksfield, Northumberland, NE43 7TN RSNE, c/o Cumbria Wildlife Trust, Gosling Sike Farm, Houghton Road, Houghton, Carlisle, Cumbria, CA3 0LD