SPRING MIGRATION STUDY Garden Peninsula Wind Energy Project Delta County, Michigan DRAFT September 2008 Report Prepared for: Heritage Sustainable Energy Report Prepared by: John Guarnaccia and Paul Kerlinger, Ph.D.* Curry & Kerlinger, LLC P.O. Box 453 Cape May Point, NJ 08212 (609) 884-2842, fax 884-4569 [email protected] * Primary Contact Garden Peninsula Wind Energy Project, Delta County, MI SPRING MIGRATION STUDY Garden Peninsula Wind Energy Project Delta County, Michigan Executive Summary Heritage Sustainable Energy proposes a utility-scale wind-energy project for the Garden Peninsula, located in Delta County on the Upper Peninsula of Michigan. The number of wind turbines has not been determined, but a leasehold map provided to Curry & Kerlinger indicates that turbines would be erected on private lands in mainly agricultural areas on the western side of the peninsula, and possibly on Little Summer Island. For the purpose of analysis, we are assuming wind turbines with a nameplate capacity of approximately 2.0 MW. The turbine towers would likely be about 78.0 meters (256 feet) tall and have rotors of about 39.0 m (128 feet) long. With the rotor tip in the 12 o’clock position, the wind turbines would reach a maximum height of about 118.0 m (387 feet) above ground level (AGL). When in the 6 o’clock position, rotor tips would be about 38.0 m (125 feet) AGL. However, larger turbines with nameplate capacities (up to 2.5 MW and more) reaching to 152.5 m (500 feet) are being considered. To assess the Garden Peninsula’s importance to raptor and songbird migration, two studies were conducted in spring 2008 at the southern end of the peninsula. The flight from Door Peninsula to the Garden Peninsula can be achieved by island hopping with the maximum overwater crossing being slightly greater than about four miles (7+ km). These studies sought to quantify: 1) the volume of raptor migration from the Door Peninsula in Wisconsin along an island-hopping route to the Garden Peninsula, and 2) the abundance and diversity of night-migrating songbirds that stopover on the peninsula. For the Raptor Migration Study, two hawk watches were established at the southern end of the Garden Peninsula, one near Fairport and the other on Burnt Bluff. Two hours of observation were conducted at each site on 23 days from April 30 to May 31. Data collected included species, number of individuals, date and time of observation, direction of flight, flight type, and flight height. These data were also collected for landbird and waterbird migrants noted. Observational details are provided in the report. The spring study confirmed that a relatively small number of northbound raptors of thirteen species use the Garden Peninsula on a migration track that departs Wisconsin’s Door Peninsula. Raptor migration at Fairport (HW1) was measured at 7.3 birds/hour (335 birds in 46 hours), with about half of the raptors appearing to have used an island-hopping route from the Door Peninsula. At Burnt Bluff (HW2), raptor traffic was measured at 10.7 birds/hour (493 birds in 46 hours), with about one fifth of raptors apparently arriving over water from Wisconsin or other points. The greater raptor traffic rate at Burnt Bluff was probably attributable to resident Turkey Vultures, which were suspected to nest on the bluffs. Excluding vultures not judged to have Curry & Kerlinger, LLC – September 2008 © 1 Garden Peninsula Wind Energy Project, Delta County, MI originated from Wisconsin, the traffic rates would be similar – 6.0 birds/hour at HW1 versus 6.5 birds/hour at HW2. Compared with Great Lakes raptor migration sites that are regularly monitored in spring, the migration rates recorded in the Garden Peninsula study were relatively low, about one tenth of that recorded at the Whitefish Point and Straits of Mackinaw hawk watches in Michigan. There are various reasons for this. The Garden Peninsula is not a spring migrant “trap” or “bottleneck” such as occurs at Whitefish Point and the Straits of Mackinaw. Both of these sites are at the southern shore of a large body of water as opposed to the Garden Peninsula, which is on a northern shore. It appears that only a small percentage of the raptors migrating across Wisconsin in spring are funneled into the Door Peninsula and cross to the Garden Peninsula. This study found that peak spring migration along Door-Garden Peninsula route occurred on southerly winds and involved mostly Broad-winged Hawks. There was also one instance of wind drift on northerly winds bringing Broad-wings to the Garden Peninsula possibly from the base of the Upper Peninsula. Regarding the fall raptor migration dynamic on the Garden Peninsula, a site visit conducted by Curry & Kerlinger on September 8-10, 2007, noted that migrating raptors were quite numerous (nine species recorded, about 450 individuals recorded in three days), especially toward the southern part of the peninsula and on Little Summer Island. The most numerous raptors were Broad-winged Hawk and Sharp-shinned Hawk. Interestingly, most of the raptors (and also many hundreds of Blue Jays, another daytime migrant) did not attempt crossing water to the Door Peninsula. Instead, they turned around at the southern end of the peninsula and headed back north along the peninsula’s western side, a phenomenon that has also been recorded at other peninsulas, particularly Cape May, New Jersey, and Whitefish Point, Michigan. Therefore, hawk migration occurs along the Garden Peninsula in both the spring and fall seasons. But, the traffic is probably greater in fall, indicated by the fact that hawk watches along the western shore of Lake Michigan only operate in that season. This is similar to large flights of hawks along the north shore of several Great Lakes during fall. Flight height of raptors reaching the Garden Peninsula in spring was generally high (i.e., above the rotor-sweep area [RSA]). Given the low migration volume and the predominantly high flight altitude, collision risk to migrating raptors in spring would appear to be low. Regarding special-status species, the Michigan-threatened Bald Eagle was the third most abundant raptor recorded in the spring study (at about one bird/hour), after Turkey Vulture and Broad-winged Hawk. Given that only 35% of Bald Eagles recorded at Fairport were judged to have migrated from Wisconsin, it appears likely that some of the records were of resident birds recorded more than once or wandering individuals. Most Bald Eagles were recorded in the high- height zone, especially at Fairport. Regarding other special-status raptors, the 16 records of Michigan-threatened Merlin at Burnt Bluff (HW2) may have resulted from a pair nesting on the bluffs. Merlin height use at both observation points was predominantly low (below the RSA) and birds may have been hunting as opposed to migrating. The Michigan-endangered Peregrine Falcon was more frequent at HW1 Curry & Kerlinger, LLC – September 2008 © 2 Garden Peninsula Wind Energy Project, Delta County, MI (6 records) than at HW2 (one record). At HW1, five of the six Peregrines appeared to have originated from Wisconsin, indicating they were migrants. One-half (50%) of these birds were in the high altitude category, whereas 33% were in the middle category (i.e., in the RSA), and 17% were low. Other listed raptors (Michigan-threatened Osprey and special-concern Northern Harrier, Cooper’s Hawk) and Northern Goshawk were infrequent, and their flight behavior did not suggest particular risk from wind farm operation. For landbirds and waterbirds in spring, abundance and flight height did not suggest heightened risk of collision. Blue Jay was by far the most abundant landbird migrant, favoring an island- hopping route through Fairport (HW1). Blue Jay traffic at Burnt Bluff (HW2) was a third that at Fairport. Flight eight of Blue Jays and other landbirds was predominantly low. Waterbird diversity was greater at Fairport, where more birds were observed resting or foraging on the water, but migration traffic was about equal between sites. For the Stopover Ecology Study, six point counts were established within two miles (3.2 km) of the tip of the Garden Peninsula, with three in the vicinity of Fairport and three in the vicinity of Burnt Bluff. In each area, point counts sampled habitat use in forest, forest edge, and grassland. Point-count circles extended to the limit of visibility, as the goal of the study was to determine whether or not birds were making stopovers and, if so, in what numbers and habitats. Each circle was sampled for 15 minutes on 23 days from April 30 to May 31, beginning after dawn as soon as light allowed for bird identification. For each observation, the following data were collected: point-count number, date, time, bird species (using standard four-letter codes), number of individuals, and behavior (coded either F, in flight, or P, perched). Stopover of Neotropical migrants and related species was found to be minimal on the Garden Peninsula in spring. When all habitats were pooled, the highest daily diversity was 16 species, and the highest daily abundance was 19.2 birds/hour. On most days, these values were much lower. A published weather-surveillance radar study indicates that most of the migration occurs to the west of the peninsula. In fall, however, significant stopover may be expected, because the migration direction is perpendicular to the peninsula and headed over Lake Michigan. At dawn, birds over Lake Michigan in the vicinity of the Garden Peninsula apparently reorient themselves toward the peninsula. A September 2007 site visit conducted by Curry & Kerlinger qualitatively confirmed greater stopover on the Garden Peninsula in fall, as well as “morning flight,” – essentially a continuation of the migration after dawn – with many songbirds flying above the treetops on what appeared to be a reverse migration to the north within the peninsula.