Study 109: AERIAL INVENTORIES OF WATERFOWL IN ILLINOIS Job 109.1: Inventory waterfowl along the Illinois and central Mississippi rivers during fall and winter. Objectives: 1) Inventory waterfowl and American coots along the Illinois and central Mississippi rivers during fall migration using light aircraft. 2) Compute use-days and peak abundances for observed species. 3) Provide general inference regarding the distribution of waterfowl in space and time. 4) Compare these data to recent and long-term averages. 5) Summarize and distribute these data for parties of interest. We completed 16 aerial inventories of the Illinois (IRV; Hennepin south to Grafton) and central Mississippi river valleys (CMRV; Grafton north to New Boston) between August 2011 and January 2012. Habitat conditions for waterfowl in the IRV were ranked average during fall 2011; however, wetland conditions for waterfowl were the best observed since fall 2005. Waterfowl habitat conditions in the CMRV were considered below average during fall 2011 and similar to fall 2010. Peak abundance of ducks inventoried was higher in the IRV and CMRV in 2011 than 2010. In 2011, peak abundance of total ducks in the IRV was 286,920; this estimate was 5% higher than the 2010 peak (274,180), and 22% above the most recent 5-year average (2006–2010; hereafter, 5-yr average) of 234,938. Total duck abundance in the CMRV was 380,025 (58% higher than 2010 [241,010]; 3% above the 5-year average [367,944]). 4 Study 110: ECOLOGY OF SPRING-MIGRATING CANVASBACKS AND LESSER SCAUP IN THE CENTRAL ILLINOIS AND MISSISSIPPI RIVER VALLEYS Job 110.1: Ecology of spring-migrating Canvasbacks and Scaup in Illinois. Objectives: 1) Aerially estimate abundance of lesser scaup and canvasbacks during spring migration in the Illinois River and Pool 19 of the Mississippi River of Illinois. 2) Document distribution of lesser scaup and canvasbacks among and within wetlands of both river systems. 3) Evaluate spring habitat composition and quality (e.g., forage abundance) within wetlands where concentrations of lesser scaup and canvasbacks occur (i.e., as determined by Objective 2). 4) Investigate and quantify behavior of lesser scaup and canvasbacks to estimate the functional response of these species to variation in habitat. 5) Leg-band 1,000 lesser scaup and 500 canvasbacks on the Illinois River to provide data that can be used to estimate survival, recovery rate, and fall distribution of these species using stopover habitats in Illinois during spring. To evaluate the quality of wetlands used by lesser scaup (Aythya affinis) and canvasback (A. valisineria) in the Illinois River valley (IRV) and at Pool 19 of the Mississippi River, we quantified abundance, distribution, and behavior, and evaluated habitat components (e.g., food availability) to provide data critical to effectively allocating conservation efforts and guiding habitat restoration and conservation planning. We documented fewer diving duck use-days in the IRV (2,106,435) than Pool 19 (2,417,865) during spring 2012. Overall, lesser scaup and canvasbacks spent the majority of their time foraging, resting, or in motion, and both species fed more in the IRV than on Pool 19. Generally, the IRV contained greater (454%) mass of seeds and tubers than Pool 19, and this trend was consistent across wetlands used by lesser scaup (527%) and canvasbacks (769%). Benthic invertebrate mass was much greater (>900%) at Pool 19 than in the IRV—thus, diving ducks likely were not limited by food at Pool 19, but may have had to search for and exploit the most profitable foraging patches in the IRV because food abundances were considerably lower. 5 Both species foraged in locations with greater benthic invertebrate mass at approximately 60% of wetlands surveyed (69% in the IRV and 36% at Pool 19) and feeding locations contained 240% and 130% more mass than random locations in the IRV and Pool 19, respectively. Overall, nektonic invertebrate mass was low, but it was greater in the IRV than Pool 19 in both random (346%) and feeding locations (130%). We banded 997 lesser scaup and 7 canvasbacks from 2–8 March, 2012 on Emiquon Preserve in the IRV. To date, we have received only 1 band return (captured and released on Pool 19), but anticipate increasing numbers of band returns following additional summer banding and fall-winter waterfowl hunting seasons in 2012. 6 Study 111: STATUS OF LARGE WADING BIRD COLONIES IN ILLINOIS Job 111.1: Monitoring of Great Blue Heron and Great Egret Colonies and Nesting Bald Eagles in Illinois. Objectives: 1) Determine the current status (i.e., active or abandoned) of known great blue heron and great egret colonies in Illinois. 2) Estimate the number of nests by species in occupied colonies. 3) Identify the UTM coordinates of new wading bird colonies. 4) Incidentally identify bald eagle nests observed along survey routes. We aerially searched 411 waypoints of known wading bird colonies (i.e., great blue heron [Ardea herodias] and great egret [Ardea alba]) and bald eagle (Haliaeetus leucocephalus) nests in Illinois from 4 April to 8 May 2012. We grouped waypoints representing eagle and wading bird nests into seven flight plans that encompassed the entire state. We marked new nests and colonies (those incidentally encountered but not in the current database) with a new waypoint and recorded pertinent data. We identified 148 active eagle nests and 95 active wading bird colonies in Illinois and along the shoreline of the Mississippi, Wabash, and Ohio rivers bordering Illinois. Comparisons with previous surveys (data provided by IDNR) indicated that the number of wading bird colonies in Illinois were stable. We found 95 active colonies in 2012 as compared with 92 colonies that were most likely active in 2001. However, the estimated number of great blue heron nests in active colonies has declined from 129.4 nests in 2001 to 81.3 nests in spring 2012, and nearly all wading bird colonies along the Illinois River south of Peoria were vacant during spring 2012. Conversely, the number of active eagle nests (n = 148) identified during spring 2012 increased substantially from known nests in 2001 (minimum of 70 nests). Bald eagles are expanding their nesting distribution in Illinois. We documented 70 new bald eagle nests and 19 new wading bird colonies in Illinois during spring 2012.