Google Earth Used to Hunt Sharp-Shinned Hawk Nests in Wisconsin By Michael O’Keefe (Blue Grass, IA) There are more than 50 thousand acres of state forest lands in southern Wisconsin – some of which are prime nesting habitat for Sharp-shinned Hawks. Finding good habitat can be difficult. Finding good habitat when you live 200 miles away can be downright daunting. Fortunately, I discovered there are some new inexpensive tools that can make this task much easier. Google Earth is free mapping software that allows you to do much of an initial nest search from home. Google Earth knits together online aerial photographs of the entire U.S. into a seamless map, allowing you to scan large areas for likely habitat. Sharpies nest in pine forests which are especially easy to identify on aerial photographs. Figure 1 shows about 15 square miles in Wisconsin including part of a state forest. Within this area I was able to mark and label as possible Sharpie nesting habitat 27 pine plantations on public land. However, to determine just how good the habitat is it is necessary to know the tree size more accurately than can be determined from photographs. This required a short visit to each site. Google Earth made it easier to find all these locations by allowing me to download the coordinates for all the sites onto my computer; they then could be uploaded as waypoints onto my hand-held GPS. This allowed the GPS to direct me to each site. GPSBabel software translated the Google Earth coordinates into a form my GPS would accept and EasyGPS software actually uploads them to my unit. Both software packages are free and available online. This initial visit required only a few minutes at each location -- enough to measure the height of a typical tree with an inclinometer and its diameter with a diameter tape. I was able to take measurements and travel between 20 sites in about five hours. Back home I used the measurements and a close-up view from Google Earth (see Figure 2) to see how well each site matched typical nesting site characteristics determined by Trexel (1999). Based on this information I gave each site a nesting habitat score of 0-6 (6 being best). Of the 27 areas identified in Figure 1, four (15%) earned the highest possible nesting habitat score of six. I searched for nests in three of these areas (about 60 acres total). In one of these three I found an active nest. Figure 2 shows the area where the nest was discovered. A short video of my inspection of the nest is posted on YouTube (see References Cited). The eyesses in that nest were over twenty days old, older than I wanted. But that really didn’t matter because I also had found a workable way to search for nests partly from home and a list of high quality Sharpie nesting habitats ready for the start of the next nesting season. References Cited EasyGPS [Computer software and manual]. Retrieved Aug 9, 2009 from http://www.easygps.com/download.asp Google Earth [Computer software and manual]. Retrieved Aug 9, 2009, from http://earth.google.com/download-earth.html GPSBabel [Computer software and manual]. Retrieved Aug 9, 2009, from http://www.gpsbabel.org/download.html Sharp-shinned Hawk Nest [Video file] Available from YouTube, http://www.youtube.com/watch?v=FoR_QE1Lzz8 Trexel, Dale R., et al. 1999. Comparative Nest Site Habitats in Sharp-shinned and Cooper’s Hawks in Wisconsin. Wilson Bull. 111:7-14 Figure 1. Google Earth view of 27 pine plantations on public land identified as possible Sharp-shinned Hawk nesting habitat. The number indicates the habitat quality from 0-6 (6 is best). The pushpin (McMiller 2) marks a plantation not yet visited. Figure 2. Close-up of 49 acres near the middle of Figure 1. This is one of three pine plantations searched for nests during the 2009 nesting season. An active nest was found here. I added the cover type labels for clarity.
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