There is increasing concern about the distribution, population status, and habitat loss for both diurnal and nocturnal raptors. Further understanding of the distribution, relative abundance, and density of wildlife populations would be valuable to make sound management decisions. Birds of prey occupy the top of the food chain and may be susceptible to environmental toxins and contaminants, making them important to monitor as indicators of environmental health.

Due to their nocturnal behavior and time of breeding, owls often go undetected using traditional methods to monitor bird populations (e.g. Breeding Bird Survey routes, Breeding Bird Atlases, Christmas Bird Counts, and migration monitoring). Several regions in the United States and Canada have effectively implemented volunteer-based nocturnal surveys in an attempt to monitor owl populations.

In 2005, a large scale, long-term survey to monitor owl populations was implemented in the Western Great Lakes region ( Wisconsin and Minnesota). The Owl Monitoring survey will provide valuable information about owl populations in the region. Volunteers will be asked to conduct owl surveys along currently existing randomized routes in the northern forest region of Minnesota and in Wisconsin.

Goals of the Owl Monitoring Project

The main goal is the continuation of this survey in order to address the listed objectives (see below), and to provide the general public with an opportunity to participate in a research project collecting valuable information about owls in the region. Additionally, we hope to increase the number of routes surveyed in the region and encourage surrounding states to implement the protocol.

Objectives of the owl survey are to:

• Understand the distribution and abundance of owl species in the region.
• Estimate trends in the relative abundance of owls in the region.
• Compare trends in surrounding areas and analyze whether these trends could be scaled up or down on the landscape.
• Determine habitat associations of owl species in the region.

Methods

A standardized volunteer-based owl survey will be implemented to collect data throughout Wisconsin and in northern Minnesota. The use of standardized methods to monitor owl populations will allow for comparisons of data collected throughout North America.

Survey routes in Wisconsin

The Wisconsin Breeding Bird Survey (BBS) routes will be used to conduct owl surveys. There are currently about 92 Active BBS routes scattered throughout Wisconsin. You can see where the existing BBS routes are in Wisconsin by going to the http://www.pwrc.usgs.gov/bbs/results/routemaps/wisconsin.htm website.

Route distance and listening period

Each survey route will consist of 10 survey stations spaced 1 mile (~1.6 km) apart. Please be aware that listening stations should be spaced 1 mile apart based on your car odometer reading.

A two-minute “passive” listening period will be done at each designated survey station along the route. After a volunteer exits the vehicle, it would be a good to walk ~20 steps in either direction to avoid detecting any vehicle noise. At a minimum, please wait a minute or so before starting the two-minute listening period.

Playbacks will not be used, given the logistical and standardization concerns with broadcast equipment.

Note: Given the number of stations (10/route) and the two-minute listening period, each route surveyed should take less than 1.5 hours to complete.

Route maps

Route maps will be provide to each volunteer. Routes will be highlighted on the map, and a brief written description of the route included.

Starting point for route

The starting point for each route will be labeled on the map in a bold “ SP”. The starting point will be designated Station 1.

Also, we currently do not have GPS coordinates for starting points or additional stations along each route. If volunteers have a GPS unit, please use them to obtain coordinates for each owl survey station along the route (please use the WGS 84 datum to collect GPS locations).

Note: It may be useful to drive the owl survey route during daylight in order to become familiar with the written directions and landmarks used on the map.

Data to be recorded

At the start of each route the route number and name, time, temperature, moon visibility, cloud cover, precipitation level and type, and snow cover and depth will be recorded on a data sheet, which will be provided.

Wind speed and noise level will be recorded on the data sheet at each station along the route. A wind speed table and description of noise levels will be provided to each volunteer.

Every stop 1 mile apart along the route is considered a Station, and there are 10 Stations/route. The data sheets include a list of stations where owls are to be recorded. Each owl detected at a Station (Stations 1 through 10) will be recorded individually, including the direction (compass bearing in Azimuths (requested if possible) or N, NW, NE, etc.) and estimated distance from the station. The distance categories are: (1) = < 100 m, (2) = > 100 m to 500 m, (3) = >500 m to 1000 m, (4) = >1000 to 1500 m, and (5) = >1500 m.

Note: If you suspect that an owl detected from a previous station (or stations) is being heard at the current station, please note this in the comments section on the data sheet. Also, the species of each owl detected should be written on the data sheet (e.g. Great horned owl, Barred owl, N. saw-whet owl, Long-eared owl, Short-eared owl, Great gray owl, Boreal owl, E. Screech owl, and N. hawk owl).

For each station on the data sheet there are two boxes labeled [During First Minute] and [During Second Minute], an “X” should be placed in either box depending on the time when each owl detected was heard calling. Please note if the owl was detected in both minutes. Also, if a new owl is detected before or after the 2 minute listening period, please note this in the comments section.

When to conduct an owl survey

If possible, it would be good to conduct an owl survey when winds are less than 10 mph and little or no precipitation. However, if your schedule does not allow for flexibility, surveys should only be conducted on a day with minimal wind ( < 15 mph).

Note: If weather conditions deteriorate while conducting an owl survey, please make an effort to complete the survey, making note of the weather change on the data sheet.

Time of year when the owl surveys should be conducted

Volunteers should attempt to survey their assigned route one time during each of the three periods (Period 1 = March 11 to 19, Period 2 = March 20 to April 9, and Period 3 = April 10 to 23). Conducting 3 owl surveys per route will allow for testing the seasonal difference in calling activity of various owl species, which will also be useful in determining peak calling periods.

However, if a volunteer is unable to conduct a survey in all three periods, it will be possible to conduct one survey in Period 2 (March 20 to April 9). Please do not hesitate to conduct two surveys if you cannot conduct a survey in one of the three periods. Any additional survey data will be useful to better understand calling activity.

Time of night when the owl survey should be conducted

Volunteers will be asked to conduct owl surveys at night, starting at least one half-hour after sunset. Volunteers should make sure to check local sunset times for the county in which they are conducting a survey.

Note: Volunteers conducting 3 owl surveys per route should make an attempt to survey the route during the same time in each survey period, adjusting for the change in daylight length and Daylight Savings Time.

Volunteer Release of Liability Form

Each volunteer conducting a survey should read the Release of Liability Form. Forms should be signed and mailed to Dave Grosshuesch (address below). Please make sure to mail the Release of Liability Form before conducting an owl survey.

Volunteer Effort Sheet

Each volunteer should keep track of the miles traveled and hours spent conducting owl surveys on the Volunteer Effort Sheet. If you are conducting more than 1 owl survey, please make sure to fill this information out after each survey. This form should be filled out and mailed to Dave Grosshuesch (address below) after all the surveys are completed.

Where to send the data sheets and other forms

If you are conducting one survey, please mail the Data Sheets and Volunteer Effort Sheet after the survey has been completed. If you are conducting three surveys, please mail the above mentioned materials after the last survey has been completed.

All materials should be returned to:
Dave Grosshuesch, 5426 Juniata St., Duluth, MN 55804.

Equipment provided to Volunteers

The Coordinating organization will provide volunteers with the following equipment:

• Instruction Booklet
• Training CD of owl calls and possible confusing species
• Data sheets
• Route map
• Volunteer Insurance Waiver Form
• Volunteer Effort Sheet

Equipment Volunteer needs to provide

Each volunteer will need to bring the following equipment when conducting an owl survey:

• Warm clothes – Please make sure to bring warm clothes, because the weather can drastically change during this time of year.
• Flashlight or headlamp
• Thermometer – To record the temperature at the start of each route.
• Compass – To record the direction of each detected owl.
• GPS unit (if you have one) – GPS coordinates will be provided for the starting point of each route.
• Stopwatch/clock – To time the 2 minute listening period.
• Pen or pencil – If using a pen, make sure it is waterproof.
• Clipboard

Safety considerations

Your safety and comfort are very important to us while conducting an owl survey. Please consider the following safety tips before conducting an owl survey.

• If at any time you feel uncomfortable or unsafe for any reason, do not hesitate to discontinue the owl survey.
• Please do not conduct a survey if the weather conditions are unfavorable for travel.
• Please do not travel on roads along the route that are unsafe because of snow or ice. If possible, terminate the survey and return at a different time.
• If possible, a survey should always be done with a minimum of two people.
• Please make sure to have a safety kit in your vehicle. Items to consider bringing are: blankets, flashlight, extra food and water, first-aid kit, shovel, jumper cables, and cell phone.
• Please make sure to pull off the road at every station so passing vehicles can get by without any trouble.

Data considerations

There are a few things to consider while conducting an owl survey:

• If there is more than one volunteer helping with an owl survey, make sure that only ONE person listens for owls at each station. If another volunteer detects a different owl, the owl should be written down in the comments box for the designated station.
• Please make sure to only record the owls detected during the timed two-minute listening period, noting any additional owls in the comments section.
• Please remember that it’s possible no owls will be heard while doing a survey, and that recording no owls is still valuable data.

Thanks to all the volunteers for helping with these surveys! Although there may be nights when conducting surveys seem to be “fruitless”, the data collected will be very beneficial in our understanding of owl populations in the Great Lakes Region. We appreciate your time and effort in this survey, and we will be sending all volunteers a report at the end of the owling season!

If you have any questions or concerns about the information included in the Owl Monitoring Instruction Booklet, etc. please contact Julie O’Connor at JPMCOCON@aol.com or call (218) 348-2291; or Dave Grosshuesch at dgrosshu@nrri.umn.edu or call (218) 525-7253.