MOON MONITORING OF OWLS AND NIGHTJARS REPORT Chuck-will’s-widow Photo by Terry Esker Tara Beveroth ([email protected]) PRAIRIE RESEARCH INSTITUTE ILLINOIS NATURAL HISTORY SURVEY Mark R. Ryan, Executive Director Eric Schauber, Director INTRODUCTION Region – “A fairly common summer resident. Although not so numerous as formerly, they still In the spring of 2008 Monitoring of Owls occur throughout the area”. Unfortunately, the and Nightjars, MOON, was initiated. MOON same statement could not be said today. While is a volunteer based program that occurs Common Nighthawks and Eastern Whip-poor- throughout the state of Illinois, and more wills can be found throughout the state their recently a few counties in Iowa. Based on numbers continue to decline. Chuck-will’s- previous research conducted throughout the widow is found in the lower southern portion U.S. and Canada we know that there are certain of the state and is currently listed as Threatened criteria that are important when monitoring for in Illinois. Loss of habitat, and food availability owls and nightjars. The MOON protocol was are thought to be the main reasons for decline. formulated in collaboration with a number of partner organizations throughout the midwest Why volunteer for a MOON route and northeast. Volunteers monitor routes that are located along suitable habitat for owls and If you are a bird lover and noctunal person by nightjars anywhere from late-April to mid-June. nature, or just an early riser, MOON might be a Most routes are 9 miles long with 10 stops fun volunteer opportunity for you! The calls are per route. In areas that are greatly develped simple and easy to learn and you don’t have to a 10 stop route is not always possible, and the learn too many. The data collected can help track route is abbreviated. Primary species that are trends and abundance over broad scales. Data monitored are Great Horned Owl, Barred Owl, collected can also help to investigate declines Eastern Screech Owl, Barn Owl, Eastern Whip- in specific species. With these data we can use poor-will, Chuck-will’s-widow, and Common habitat modeling to further aid in making sure Nighthawk. Other species that may also occur we are using the best management practices for that may be recorded are Northern Saw-whet Owl and Nightjar Convervation. Finally, another Owl, Short-eared Owl, and American Wood- unique thing about MOON is that volunteers cock. Barn Owl is currently listed as threatened that are proficient with audio bird identification in Illinois and the Short-eared Owl is currently are encouraged to monitor for all species they listed as endangered. The Eastern Screech-Owl hear during the listening period. This additional is found in low numbers on BBS routes (BBS data can give us additional insight into the life data), the Great Horned Owl is widespread and histories of other species. We are always looking the Barred Owl, which, historically, was listed to recruit more volunteers, so if you would like as rare, is now found throughout the state. The to volunteer please contact beveroth@illinois. Northern Saw-whet Owl is found primarily in edu. the very northern part of the state, which is the southern edge of its border. As far as nightjars Fun MOON Highlights since 2008 go, in 1934 Ford et al. were quoted as saying this of the Whip-poor-will in Birds of the Chicago ▷ A grand total of 4,111 birds of 10 owl and nightjars species from 75 routes have been recorded. ▷ Eastern Whip-poor-will detections to date total 1,406. ▷ County with the greatest # of Eastern Whip-poor-will on a route: Illinois, JoDaviess (28); Iowa, VanBuren (44) ▷ County with the greatest # of Chuck-will’s- widow on a route: Johnson (13) Illinois, Iowa, VanBuren (44) ▷ Barred Owl was the most common species found with presence at 61 of the 75 routes. Common Nighthawk Photo Loren Merrill. 2 Monitoring of Owls and Nightjars METHODS *Monitoring Times Routes are surveyed two times each year. These surveys should be conducted at least 30 minutes following sunset (when the moon is above the horizon) and end no later than 15 minutes prior to sunrise. Surveys are completed during times when the moon is 50% or greater illumination. 2019 monitoring windows were May 12 - May 26 and June 10 – June 24. Monitors were asked to monitor one time/window. Weather is a great determining factor when deciding which day to monitor during the open windows. It is recom- mended that monitoring be performed when the moon is above the horizon and not obstructed by clouds. Nightjars call less frequently when the moon is below the horizon or hidden by Eastern Screech-Owl Photo by Jen Mui. cloud cover. *Route Selection code (Appendix A). Listening period may vary depending on whether or not playback Most of the MOON routes were randomly (optional prerecorded bird call/song) is used. A selected based on forest habitat available in the passive listening period of six minutes should be state. However, there are some routes that have completed at each stop. The detection history of been formed, or altered by volunteers, due to each individual seen or heard from the time of being near urban areas, or problems with route their first detection through their last detection stops. Most routes consist of 10 stopping points should be recorded in the appropriate 1-minute where volunteers stop, get out of their vehicle, block of the data sheet (each individual bird and listen for nightjars and owls. Each stopping detected will have their own row on the data point should be at least one mile apart. Also, sheet, Appendix B). A value of 1 is used if there given the topography of the state, and the layout is a detection, and if there is not a detection of many roads, routes may differ greatly in the minute column can be left blank. Even if appearance. Volunteers are encouraged to scout an individual calls more than one time during their routes ahead of time. a one minute block it is still only recorded as a 1 for that block. Birds will sometimes move *Monitoring during the counting period. Volunteers are asked to use their best judgement to distinguish Monitoring should be done from a stationary new individuals from those individuals already position outside of one’s vehicle. Most impor- detected. If unsure if a different individual is tantly, be consistent. The same technique should calling, a new individual should not be recorded. be used at each stop including how volunteers focus for listening for nearby birds and distant If there are no birds detected at a stop NONE birds. should be entered in the species column on the data sheet on the same line as that stop number. Stop # and time should be recording at the beginning of each stop listening period. Species If a volunteer does not use playback they only detected are recorded using a four-letter alpha need to listen at each stop for 6 minutes. 3 Monitoring of Owls and Nightjars If a volunteer chooses to use playback they will that came out in Science, Sept 2019, showed play two prerecorded calls at the end of the initial that nearly 3 billion birds have disappeared 6 minute block. A two-minute listening period since 1970 (Rosenberg et al 2019). What is will follow each of the species calls. The first even more surprising, and worrisome, is that, call will be an Eastern Screech-Owl call for (20 according to the study, common birds have seconds). Following the Screech owl playback suffered the greatest losses. Because the SBC listening period a Barn Owl call (20 seconds) will dataset dates back to 1972 this prompted us to be played. Listen passively for an additional 2 compare our data with the Rosenberg study to minutes following this playback. see if our data is showing similar trends. We looked at the SBC trends of five species, Horned Birds should be recorded as they are heard, and Lark, European Starling, Eastern Meadowlark, not at the end of the listening periods. Red-winged Blackbird, and Common Grackle, that are declining throughout North American, Other Species: Volunteers are encouraged to according to the study by Rosenberg and record any species they hear calling while moni- toring. If something is heard, but the volunteer is unsure of the identification, nothing should be recorded. But, for instance, if the call is identified, colleagues. While we would have expected all such as a Sedge Wren, or a Henslow’s Sparrow, Song Sparrow Photo by Patty Dickerson. the species is recorded in the same format as a target species. five species to show declines we found that Horned Lark, Common Grackle and Eastern Meadowlark have declined according to SBC RESULTS data, but European Starling and Red-winged Blackbird populations have remained stable in MOON 2019 Results Illinois, according to the SBC (Figure 1 & 2). There could be a couple of reasons we did not see There were 28 MOON routes monitored in 2019, declines in these two species. One being SBC is including four in Iowa. There were a total of 488 a count that takes place during spring migration. Owls, Nightjars, and Woodcock detected (Figure Bird numbers may vary year to year. Another 1). Total numbers of each target species detected possibility is that we are not paying as much in Illinois and Iowa combined was as follows: attention to counting these birds as we might Barred Owl (202), Eastern Whip-poor-will with a less common bird such as a Henslow’s (190), Chuck-will’s-widow (34), Great Horned Owl (28), Eastern Screech-owl (19), American Woodcock (5), Barn Owl (4), and Common Nighthawk (4).