Eastern Screech-Owl Survey INSTRUCTION MANUAL

Transcription

1 Eastern Screech-Owl Survey INSTRUCTION MANUAL Ontario Breeding Bird Atlas c/o University of Guelph Blackwood Hall, Room 211 Guelph, ON N1G 2W

2 TABLE OF CONTENTS INTRODUCTION 1 ONTARIO EASTERN SCREECH-OWL SURVEY GUIDELINES 2 Preparing for your survey 2 Training 2 Equipment 2 Planning your survey 3 Survey Timing 3 Time of Day 3 Weather Conditions 3 Time required 3 Completing your Survey 3 Locating designated survey locations 3 Locating undesignated survey locations 4 Determining suitable locations 4 Survey method 4 Data collection 4 Safety Issues 5 The Finish Line 5 Completing the Owl Survey data form 6 Submitting your data 9 Appendix A The Ontario Breeding Bird Atlas 10 Appendix B The Survey CD 11 Appendix C Using GPS or the map to determine UTM coordinates 12

3 INTRODUCTION Thank you for volunteering to participate in the Ontario Eastern Screech-Owl Survey. Your contribution will aid in the understanding of Screech-owl populations in Ontario. Owls represent a special challenge to monitor because they are notoriously difficult to survey. Owls breed earlier in the year than do most other species, are secretive, primarily nocturnal and roost in concealed locations during the day. For this reason, little is known about owl population trends, breeding ecology and distribution in Ontario. Playback of recorded songs is a particularly useful technique for surveying some owl species. Due to their territorial behaviour, songs broadcast within an owl's territory may elicit a vocal or visual response by the resident owl in an attempt to defend its territory against an intruder. The higher response rate elicited by the use of playback will enhance our ability to map the relative abundance of target species. Owls are fascinating, and surveying for them can be an interesting and enjoyable activity. The information provided from the will increase our knowledge of the distribution, status and conservation needs of these mysterious creatures of the night. Your participation in these surveys is greatly appreciated and will allow us to gather enough data to be able to map the relative abundance of the Eastern Screech-owl and the Great Horned Owl in Ontario. Although a playback has not been provided for Great Horned Owl, they will sometimes respond to the call of the Eastern Screech-owl. The is being undertaken as part of a larger project, the Ontario Breeding Bird Atlas. For more information on the Atlas, see Appendix A. Draft results from the Eastern Screech-owl Survey will be posted on the Atlas project web page. Maps of the Eastern Screech-owl s relative abundance and breeding distribution will be created based on the survey results and printed in the Atlas book, scheduled to be published in Thank you for contributing to the survey! Page 1

4 ONTARIO EASTERN SCREECH-OWL SURVEY GUIDELINES Preparing for your survey Training The survey playback is Track 1 of the CD. It contains the call of an Eastern Screech-owl interspersed with periods of silence. See Appendix B for complete information on the CD s contents. Although a playback is not provided for Great Horned Owl they will sometimes respond to the call of the Eastern Screech-owl. Also, you may hear them during the course of the survey. For training purposes, you should primarily focus on familiarizing yourself with the calls of the Eastern Screech-owl (Track 13 on the CD) and the Great Horned Owl (Track 7). You may also want to familiarize yourself with species that are found in smaller numbers in southern Ontario. These include; Long-eared Owl (Track 6), Barred Owl (Track 8) Northern Saw-whet Owl (Track 9) and Short-eared Owl (Track 12). Equipment Make sure you have all the required equipment before heading out. Equipment checklist As a volunteer, you will have received a volunteer kit including: v this manual, v a map of your chosen survey square, v a survey CD, v Data forms (one copy to be completed (neatly) and returned). You will need to provide: v a watch, v flashlight or head lamp, v clipboard, v compass, v portable CD player, v pen or dark pencil. Optional: v a towel to place on your car under the player. v road map v spare batteries v GPS unit, it will be very useful for finding survey locations in the dark, and for providing precise location information for other survey locations. However, you can easily perform the surveys without a GPS unit. Don t forget the thermos with a hot beverage! Page 2

5 Planning your survey Survey timing You should complete your survey between March 1 st and April 30 th. Time of day We recommend that surveys begin about one half hour after sunset, but they can be run any time between a half hour after sunset and a half hour before dawn. Weather conditions Weather has a great influence on our ability to hear owls; calm conditions are best. Wind and precipitation significantly reduce calling rates and detectability, while cloud cover is less important. Some owl calls do not carry very far, so wind is a critical limiting factor. Surveys should be conducted on nights with wind less than 19km/hr (i.e., 3 or less on the Beaufort Scale, which is enough to constantly move twigs and to extend a small flag). Extremely cold temperatures also have an adverse effect on owl response rates. For optimum response, surveys should be run on nights that are clear, calm and not too cold (use warmer than -15 C as a guideline). There is little point in attempting or continuing a survey if the wind exceeds force 3 or if there is persistent snow or rain. If you have started a survey and the weather conditions worsen during the survey to a point where they are unsuitable simply stop the survey and finish it another night. Time required It takes approximately hours to run the full 10-location survey. We recommend that you complete the survey on one single evening. If you are unable to complete the survey on a single night (i.e. due to bad weather conditions developing), simply complete the remaining stops (to make a total of 10 stops surveyed) on another night and use a separate data form to record your results. Completing your survey Locating designated survey locations There are 50 randomly selected, designated roadside survey locations within each square. These are marked on the map of each 10-km square. To select locations for your surveys, start with designated survey location number 1 and check each designated location on the map sequentially (1, then 2, then 3, etc.), until you have selected the first 10 designated survey locations that are likely to be suitable for owls. Ensure that all survey locations are at least 1 km apart. We recommend that you actually go into the field during daylight hours to locate each location. This makes it easier to find the locations when you go back after dark. If you arrive at a survey location and realize that it is not suitable, you should reject this location and find a new one among the designated locations, using the same rules as above (first check number 11, then 12, etc.). If you cannot find 10 suitable survey locations in your square using the rules above, then create your own undesignated survey locations to bring the total to 10, as described below. Once you arrive at the designated location (as precisely as you can determine it, using the map or GPS) you can move anywhere within 100m of that location to do the actual survey. So, if the Page 3

6 designated location is, say, 75m from a woodlot, you can move to the edge of the woodlot or up to 25m inside the woodlot to do the survey. If you have a GPS, and you do in fact move more than about 50m from the designated location on your atlas map, you should provide the UTM of the location where you actually did the survey. For more information on reading UTMs from GPS units see Appendix C. The 10 survey locations can be surveyed in the most convenient order (not necessarily sequentially 1-10). It is important that you run the full playback survey and complete the data form for each location, whether or not you actually find owls. Knowing where owls do not occur is just as important as knowing where they do occur. Locating undesignated survey locations There are two circumstances in which you might establish undesignated (i.e., new) locations for your owl survey. The first is if you cannot find 10 suitable designated locations and wish to add undesignated survey locations to round the total up to 10. The second is if you have completed surveying the 10 designated locations and would like do additional surveys. Undesignated locations can be set up in any spot that you think might be suitable for owls usually these would be in wooded areas. (Note that it is essential that you do not include undesignated locations known to have owls, because this would very much bias your results). Undesignated survey locations can be located in off-road locations, if you like. The UTM of each undesignated location should be recorded on the data form. For information on how to determine UTM location using the map provided see Appendix C. Determining suitable locations Suitable locations are those that are: accessible at the time of year of the survey near a safe parking spot in a quiet location with little traffic not directly in front of a house designated locations should be within 100m of suitable habitat undesignated locations should be within or adjacent to suitable habitat more than 1 km from any other owl survey location (use the map provided to check the approximate distance between locations). For the Screech-owl, suitable habitat is woodland (including small woodlots and groves of trees), orchards, urban areas with mature shade trees (including parks and cemeteries), and along streams with shade trees. Survey method Use Track 1 on the CD to perform your surveys. At each stop, put the portable player on the roof of your vehicle, push the play button and move at least 20 metres away from your vehicle. This will reduce noise interference from the engine as it cools and will enable you to hear the owls. Data collection We recommend doing all 10 survey points in one evening, but the 10 points can be done over more than one evening should that be necessary or more convenient. Fill in a data sheet even if you recorded no owl species. Negative data are as important as owl detections they help us Page 4

7 gain insight into the relative abundance of owls across the province. See page 6 for instructions on completing the data form. Safety issues We highly recommend that you have a friend accompany you on owling outings. He or she provides a safety factor, and can help with the survey juggling the CD player, map, GPS, flashlight and data forms can be challenging for one person. It s a good idea to let someone know where you plan to be travelling, and when you expect to return. Roads should be accessible at the time of your survey. We are also concerned about your safety. Dress warmly. Please be careful when standing on roadsides at night and while driving on wintery roads. On snowy roads, be careful when pulling off to the side of the road as it is easy to slide one or two wheels into the ditch. Be sure to test your playback equipment before heading into the field. If possible, test the equipment on a still night. To do this, try to find a straight, reasonably flat road and play the CD at the maximum volume that does not cause distortion. As the CD is playing, walk away from the player, stopping at 100m intervals to listen. Indicate on your data form how far away you can hear the call. Call broadcasts are effective in locating and studying owls but should not be used indiscriminately. Responding birds may continue to vocalize for some time after the playback ends, and therefore may be more easily located by predators. In addition, frequent and persistent playbacks may affect the normal activities of the owl. Enjoy the experience but please keep disturbance to a minimum. Remember that the health and welfare of each bird is our utmost priority. The finish line Once you have surveyed the 10 locations, you have completed the minimum requirement for the survey in that square. Congratulations, and thank you! If you were not able to complete all 10 stops, please try to complete the remaining stops on another night. Simply fill out a second data form and submit both forms. If you are not able to complete the remaining stops on another night, please send in the results for the stops you were able to complete. This information will still be usable in the final analysis. If you completed 10 stops and would like to do additional surveys you can either; 1. select another square to survey. See the website for the list of available squares or contact the Atlas office. 2. repeat the same 10 stop survey at another time of the year (anytime between November- April). If you choose to do this, please make sure you send in your original data sheet as soon as possible. 3. complete more stops within the same square. Page 5

8 Completing the Owl Survey Data Form Use dark pencil or pen. Your form will be read by a computer scanner. To reduce scanning errors, please write legibly in block capitals and write within each box, without touching the sides. See the sample completed form below We have enclosed two data forms for you. If your field form is messy, please recopy your results onto the second form and submit this form. Example of a completed data form Square ID, and Region (Number), should be filled in for you. If they are not, look at the square number and region number listed on the bottom right corner of your map, and fill these numbers in on the data form. Name, registered atlasser checkbox- Fill in your full name. If you are a registered Ontario Breeding Bird Atlas participant, fill in the bubble marked Registered and enter your ID number in the box provided. If you are not involved in the Atlas, but have volunteered strictly for the owl survey, please fill in the bubble marked Non Atlas Participant. Date: Record the month, day and year of your survey. If you have done the survey on more than one night, use a new data form for each night. Maximum Distance at which playback can be heard. This information is optional. It can help ensure that future surveys set their equipment to about the same volume level, which will increase standardization. Record the maximum distance (to the nearest 100m) at which you can Page 6

9 hear the playback from your machine. In the example above, the broadcast tape could be heard at a distance of 200m. UTM Information: Fill in the bubbles to indicate whether you derived the UTMs from your map or from a GPS unit, and whether your UTMs are in NAD27 or NAD83. If you used the map provided fill in the Map bubble and the NAD83 bubble. In the example on page 6, John Smith used the map provided to record UTM and therefore used NAD83. Survey Location Boxes: The form provides space for you to record the results of surveys at 10 locations in your square. Those 10 locations are given letters A-K in the Survey Location boxes. For designated locations (#s 1-50 on your square map) fill in the number under Designated Number : for these designated locations, you do not normally need to provide a UTM. However, if you do in fact move more than about 50m from the designated location on your atlas map (a move of up to 100m is permissible at each location), and you have a GPS unit, you should provide the UTM of the precise location where you actually did the survey. For undesignated locations, leave the Designated Number column blank. Fill in the UTM for each location. If you can use GPS, please do so. If not, estimate location to the nearest 100m using your atlas map see instructions in Appendix C. The letters in the Survey Location boxes correspond to those in the Location column in the main survey data table. In the example on page 6, John surveyed eight designated locations (A-D and F- J at designated location numbers 06, 17, 41, 2 etc.) and two undesignated locations (E and K). Note that for the two undesignated locations (E and K), no designated number is given, but UTM is provided. Survey Data: Each line in this table is used to record data on each individual owl reported at each survey location, i.e. one line for every bird. In the example provided on page 6 at location (A), three owls were heard: one Screech-Owl and two Great Horned Owls, and each is recorded on a separate line. If no birds are heard at a location, record the Date, Time, # cars and Noise, and leave the other columns blank. Location: Location is provided for you, using the letters (A-K) from the Survey Location table on the form. Start Time: Record the time you start the survey at that location. Use the 24-hour clock: 7:30 p.m. is 19:30. In the example, John started the survey at location A at 21:12 (9:12 pm). Species Codes: The two target species are; EASO Eastern Screech-owl GHOW Great Horned Owl. If you come across other owl species, you should also record them on your data form. Some other owls that you might come across while doing your surveys are: LEOW Long-eared Owl; NSWO Northern Saw-whet Owl; Page 7

10 SEOW Short-eared Owl; BARR Barred Owl. First Observed: Put an X in the appropriate box to indicate when you first heard the bird respond. If you first hear the bird during the 2 minute silent listening period at the start of the survey put an X in the under the column headed 2 Min Silence. The playback portion of the survey is divided into 5 intervals. Each interval contains 30 seconds of calls, followed by 30 seconds of silence. A new interval starts with the beginning of the next series of calls. If you first hear the bird call during either a 30 second call or 30 second silent period place an X in the column representing the appropriate interval. We recommend that you keep track of intervals during the survey by counting on your fingers at the start of each new interval. If you first hear a bird respond after the final beep that signifies the end of the survey, mark an X in the After Survey box. In the example on page 6, the Screech-Owl was first heard during the two minute silent listening period. Both Great Horned Owls were first heard during the first call broadcast (thus the 1 st interval). Direction: Record the one- or two-letter code to indicate the direction at which the bird was first heard or seen. N North; NE North-east; E East; SE South-east; S South; SW South-west; W West; NW North-west. In the example, the Screech-Owl was North-east of the survey location when first heard. The first Great Horned Owl was South-west of the survey location and the second was North-west when first heard. Distance: Put an X in the appropriate box to indicate the distance category (<100m or >100m) in which the bird was first heard. In the example, the Screech-Owl was less than 100 metres from the survey location. Both Great Horned Owls were more than 100 metres from the survey location. # cars: Record the number of vehicles that pass by that location during the survey period. In the example, 2 cars passed the survey location during the survey. Noise: Record number 1 to 4 based on the following scale: 1. None or slight: relatively quiet, little interference. 2. Moderate: some interference with broadcast and/or listening. 3. High: substantial interference with broadcast and/or listening. 4. Excessive noise: extreme interference with broadcast or listening. If there is excessive noise or too much traffic at one station to survey properly, we recommend stopping the survey, erasing any data that you may have recorded from that stop, and selecting a different location using the procedure described on pages 3-4. Page 8

11 In the example, there was moderate noise level during the survey. Remarks: Record comments such as what caused the noise, whether or not you saw the owl, colour phase of Screech-Owl. Colour morph: If you are able to get a good look at the Screech owl during the survey, record the colour morph (grey, brown or rufous) in the data form remarks section. Submitting your data Please submit your neatly completed data form(s), within 2 weeks of completing your survey, but at the latest by May 15 th, You should mail your form(s) to; Ontario Breeding Bird Atlas c/o University of Guelph Blackwood Hall, Rm. 211 Guelph ON N1G 2W1 If you need additional data forms you can print them from the Owl Survey web page: If you have any questions, please atlas@uoguelph.ca or call Thanks very much for trying owl surveys. We hope you enjoy them! Page 9

12 Appendix A The Ontario Breeding Bird Atlas The Ontario Breeding Bird Atlas is a five year ( ), volunteer-based project to map the distribution of all the species nesting in Ontario. It is a repeat of the first atlas ( ), and will allow an assessment of how distributions and status have changed over the past 20 years. The second atlas is also gathering data to allow mapping of the relative abundance of each species, so the most important areas in the province for each species can be determined, and compared to future atlases. Data are collected on the basis of 10-km squares. Many volunteers adopt a 10-km square, trying to find all the species that breed there. Others contribute data more casually from any square (in some cases many squares) in the province. Birders who know birds well by song are asked to also do a series of 25 point counts scattered around their square to help with the mapping of relative abundance. To ensure that the province is fully covered, the atlas requires extensive involvement of birders. All naturalists can contribute to the atlas project and the more data contributed, the better will be our understanding of bird distributions in the province, and the more useful the results will be for bird conservation. Atlassing is an enjoyable and rewarding activity. The comparison with the first atlas will provide a valuable assessment of the current status of birds. Already, it is clear that many species have changed markedly over a 20 year span. Some of these changes are cause for concern, while others give cause for optimism. The remaining two years of the project will flesh out the data base and allow comprehensive comparisons, and even investigations into the reasons behind the changes. This enhanced information will provide the basis for better bird conservation, which is, of course, what the atlas is all about! Thanks to the many volunteers whose collective efforts are contributing to the success of the Atlas project and making the project feasible. For more information on the project and how to get involved, see our web page: or contact us at atlas@uoguelph.ca; toll free phone: Page 10

13 Appendix B The Survey CD Use Track 1 for your survey. Track 1 (7 minutes): Eastern Screech-Owl playback. Starts with a double beep, followed by two minutes of silence, then; 1 st interval; 30 seconds of calls; 30 seconds of silence; 2 nd interval; 30 seconds of calls; 30 seconds of silence; 3 rd interval; 30 seconds of calls; 30 seconds of silence; 4 th interval; 30 seconds of calls; 30 seconds of silence; 5 th interval; 30 seconds of calls; 30 seconds of silence; ending with a double beep. The remainder of the CD contains: Track 2 (1 minute): This silent period has been put in to help ensure that the Boreal/Barred Owl playback does not start to play before you stop the CD. Track 3 (12 minutes): Boreal and Barred Owl playback. This playback is used to survey owls in central and northern Ontario. Starts with a double-beep to indicate the start of the first silent listening period that lasts one minute. Another double-beep marks the end of the first silent listening minute. This is followed by a second silent listening minute. Then, the Boreal Owl broadcast begins (20 seconds long), followed by another oneminute silent listening period. The Barred Owl broadcast follows, and plays for 20 seconds. This is followed by a two-minute silent listening period. This Barred Owl broadcast is repeated 3 more times, with a silent listening period between each broadcast. A double-beep marks the end of the broadcast. Track 4 (1 minute): This silent period has been put in to help ensure that the training session does not start to play before you stop the CD. Tracks 5-19 (14 minutes): Owl training. The owl training session is 14 minutes long and ends with recordings of other birds and common frogs you might hear while out owling. The order is as follows: Track 5: Great Gray Owl; Track 6: Long-eared Owl; Track 7: Great Horned Owl; Track 8: Barred Owl; Track 9: Northern Saw-whet Owl; Track 10: Boreal Owl; Track 11: Northern Hawk-Owl; Track 12: Short-eared Owl; Track 13: Eastern Screech-Owl. Track 14: Common Snipe; Track 15: American Woodcock; Track 16: Ruffed Grouse; Track 17: Wood Frog; Track 18: Spring Peeper; and Track 19: Chorus Frog. This (tracks 5 to 19) is the same training recording used by the Nocturnal Owl Survey. Track 20 (1 minute): This silent period has been put in to help ensure that the rail playback session does not start to play before you stop the CD. Track 21 (5 minutes): Rail playback. This track is 5 minutes long, and the order is as follows: Virginia Rail, Sora, Least Bittern, Common Moorhen/American Coot, Piedbilled Grebe. This is the same recording used by the Marsh Monitoring Program. Page 11

14 Appendix C Using a GPS or the map to determine UTM coordinates The Universal Transverse Mercator (UTM) grid system is the location system used for the. If you chose undesignated survey sites, or if you moved more than 50m from a designated site, you will need to record UTM Eastings and Northings on the data form. Using a GPS unit to determine UTM location If you have a GPS unit, record the location while you are on site. Set the device to NAD83, and record all 6 digits of the Easting and all 7 digits of Northing. (If your GPS unit gives you 7 digits for Easting, do not record the initial 0.) If you do not have a GPS unit, mark your location on the map as accurately as possible and figure out the UTM designation later, following the instructions below. Using the map to determine UTM location The 1-km and 500m Northings are shown along the left border of the map, and 1-km and 500m Eastings are shown along the bottom. The 1-km designations always end in 000, and 500m designations end in 500. There are 100m tick marks between the 500m and 1-km grid lines, but these are not numbered. If they were, they would end in 100, 200, 300, 400, and 600 to 900. To get the closest 100m Easting for a location, place a ruler from top to bottom on the map to determine which 100m tick mark on the bottom of the map is closest to the location. Record the 6 digit Easting of that 100m tick mark. To get the closest 100m Northing, place the ruler horizontally across the map in the same manner. Page 12