1. The Western Great Lakes Bird and Bat Observatory Lake Michigan Offshore Waterfowl Surveys Bill Mueller, WGLBBO

2. Offshore Lake Michigan Waterfowl Surveys  To learn more about the distribution of waterfowl and waterbirds in western Lake Michigan’s open waters, offshore surveys were conducted during fall, winter, and spring of 2010-2011 – with a second round of surveys in 2012. We received a USFWS Coordinated Bird Monitoring Grant for 2010-2011, and a second grant for 2012.

3. Study area: the western offshore waters of Lake Michigan, from central Door County, WI, to Chicago, IL (Surveying an area ~ 1-10 miles offshore)

4. Our Objective  Determine a more complete picture of offshore spatial and temporal distribution of waterfowl and waterbirds in western Lake Michigan’s open waters. Long-tailed Duck was the most frequently found species.

5. Observations took place from mid- October 2010 through early May 2011, and again from February 2012 through late April 2012, utilizing a twin-engine, WDNR aircraft flown out of Wittman Regional Airport, Oshkosh, WI. A double-observer protocol was used on each flight; observers did not communicate during the flight. We searched transects using parallel bands of known width.

6. WI Department of Natural Resources aircraft - a twin- engine Cessna Skymaster

7.  Surveys were conducted along transects oriented north-south and spaced 3.2 km (2 miles) apart. This spacing helped avoid double counting and allowed adequate coverage.  The fixed-wing aircraft flew at ~95 miles/hr ground speed following the mapped transects in alternating directions.  Surveys were flown at a 100 m (300 ft) aircraft altitude.

8. SURVEY BLOCK AND TRANSECTS

9.  The time of each bird sighting was recorded; position was marked via on- board GPS.  No observations were recorded in extremely rough water conditions (e.g., no more than small waves; no whitecaps)  Sampling units were single birds or groups of birds.

10.  Transect width (200 m) is established within a band with a declination in degrees from the horizon from 17-20.9° depending on altitude of the plane. Each observer uses a clinometer to establish the correct vertical declination from the horizontal during flight, to enable the observer to maintain the correct transect width.

11. Visibility o Sun Glare (direction with respect to front of plane) o Light conditions o Water surface (e.g., calm, small waves – no whitecaps, occasional whitecaps) o Observer fatigue

12.  Observation condition rating (based upon and determined independently for each side of the plane/each observer) 1. Poor visibility conditions 2. Fair 3. Good/Average 4. Very Good 5. Excellent

13. 8 MOST ABUNDANT SPECIES Species Max. Count Total Count Date & Date & % of Total Range Long-tailed Duck25,555:11/2 32,714: 47.6 Oct-May Red-breasted Merganser 9,311:1/20 20,538: 29.9 Oct-May Common Goldeneye 6,660:2/11 6,946: 9.6 Oct-May Bufflehead 429:4/29 1,447: 2.1 Oct-May Canvasback 1,030:11/2 1,036: 1.5 Oct-Nov Bonaparte’s Gull 442:5/4 442: 0.6 May Greater Scaup 401:11/2 434: 0.6 Nov Common Merganser 308:2/11 312: 0.5 Jan-Feb Other species: MALL, HOGR, TUSW, COLO, DCCO, GLGU, WWSC, GRYE

15. Door and Kewaunee counties

16. LTDU Sightings by Month

17. RBME Sightings by Month