Oral or Poster; Contributed Paper or Plenary Session #; Travel Scholarship and/or Presentation Award

Satellite Tracking Lesser Scaup and Greater Scaup from the lower Great Lakes

Shannon S. Badzinski, Long Point Waterfowl, Bird Studies Canada, P.O. Box 160, Port Rowan, Ontario, N0E 1M0, Canada E-mail:

Scott A. Petrie, Long Point Waterfowl, Bird Studies Canada, P.O. Box 160, Port Rowan, Ontario, N0E 1M0, Canada E-mail:

Extended Abstract: To date, lesser scaup (Aythya affinis) and greater scaup (Aythya marila) migration pathways and their affinities to migratory stopover sites and breedingand wintering areas largely have been inferred from either direct observation or through band recoveriesduring fall/winter. In addition, there is no specific information regarding seasonal migration chronologies or how individual birds move across the landscape during spring and fall. Advances in satellite transmitter technology now allowindividual birds the size of lesser scaup to be tracked throughout the year. Thus, we used satellite telemetry to study several aspects of the migration ecology of lesser and greater scaup captured on the lower Great Lakes (LGL) during spring. The main objectives of our research were to: (1) determine spring and fall migration pathways of LGL scaup, (2) determine the breeding and wintering ground affinities of female scaup, (2) assess spring migration chronology, specifically with respect to females and time spent outside of the LGL region until arrival at their breeding sites, and (4) evaluate among-individual and between-season patterns in migration movements.

Lesser and greater scaup included in this study were captured during early spring migration on the LGL at 2 major stopover sites in Ontario, Canada: Inner Long Point Bay – Lake Erie and Hamilton Harbor – Lake Ontario (Fig. 1). The LGL region of Canada contains some of the most important staging habitats for waterfowl, particularly diving ducks, in eastern North America.

We captured scaup by using corn (or corn and wheat mixture) baited dive-in, cloverleaf, and corral traps. From 1-5 April 2005, Dr. Glenn Olsen (USGS, PatuxentWildlifeResearchCenter, Laurel, Maryland, USA) implanted satellite transmitters (PTT-100 Implantable Version, Microwave Telemetry Inc.) into 6 female lesser

Figure 1. Stopover sites (dark points) on the Canadian side of the lower Great Lakes where lesser scaup (Aythya affinis) and greater scaup (Aythya marila) were captured during spring 2005 and 2006.

scaup (3 = 38 g PTT and 3 = 22 g PTT) at LongPointBay. During spring (11-16 March) 2006, we implanted 15 lesser scaup at LakesErie(LongPointBay: female = 10 and male = 5) and Ontario(HamiltonHarbor: female = 3) and 2 female greater scaup at HamiltonHarbor, LakeOntario with 38 g transmitters. In general, duty cycles were set such that PTTs transmitted every 3 days for spring migration periods and every 7 (2005) and 10 (2006) days during the summer, fall, and winter periods. We used only the most reliable locations (i.e., location classes: 3, 2, 1, and 0) for determining scaup locations and migratory movements.

Data currently are being collected on scaup captured and implanted with PTTs during spring 2006. As a result, those data will be presented and discussed at the 4th North American Duck Symposium. General results and conclusions drawn from our 2005 field season, however, are presented below.

Based on data collected during 2005, we found that the 22 g PTTs provided less data than did the 38 g units. Unfortunately, one bird containing a 22 g PPT died at LongPointBaybefore starting its spring migration. The remaining 2 females with 22 g PTTs departed from LongPointBay and made major migratory flights. However, locations for these 2 birds were available only for part of their spring migrations because both PTTs ceased transmitting during the middle of May. In contrast, the 3 birds with the 38 g models all provided data throughout spring migration and well into the fall and wintering periods. Based on these results, we chose to use the larger 38 g PTTs in all birds captured during spring 2006 to ensure that the maximum amount of data would be collected throughout the annual cycle.

Preliminary results to date suggested that female lesser scaup staging at Long Point during spring had very different migration strategies and chose several different migration pathways to their breeding areas. Ourfindings indicated (and corroborated earlier evidence) that prairie and parkland regions of the North Dakota, South Dakota, Manitoba, and Saskatchewan were important for spring migration of lesser scaup originating from LGL stopover sites and/or wintering areas. It also was noteworthy that female lesser scaup using the LGL during spring were widely dispersed throughout the boreal forest region of North Americaat the end of their spring migration. Specifically, 3 females ended their spring migrations, and likely attempted to breed, in boreal areas within northern Ontario, north easternManitoba, and south eastern Yukon Territory. In addition, we estimated that those 3 females spent about11, 18, and 19 days (average = 16 days) outside of the LGL before arriving at their intended breeding areas. Given that selenium is high in spring migrants on the LGL, female lesser (and greater) scaup, especially those breeding relatively close to the LGL region, may be retaining selenium and transferring it to eggs on the breeding grounds. Thus, we feel continued study of the spring migration ecology of lesser scaup using the LGL region is warranted.

Our evaluations of the fall migration pathways and wintering ground affinities of female lesser scaup using the LGL during spring revealed some noteworthy results. During fall migration 2 of 3 lesser scaup were philopatric to major stopover sites (LongPointBay– Lake Erie and Bay of Quinte – LakeOntario) on the LGL used previously during spring. It was notable that these 2 females also were the birds that attempted to breed in the eastern portion (north-central Manitoba and northern Ontario) of the species range. The female that spent the summer in the western boreal region (Yukon Territory) did not return to the LGL during fall, instead it spent nearly the entire fall migration period in the Canadian parkland/prairie region and relatively less time in the southeastern US enroute to its wintering grounds in eastern Florida. Only one other bird (i.e., the female using the Bay of Quinte, LakeOntario during fall) provided data on wintering ground locations; this bird remained on eastern LakeOntario throughout the entire winter of 2006.Our results suggest that at least some spring-staging lesser scaup using the LGL originate from major wintering areas in the southern portion of the Atlantic Flyway.Our data also show that in some years at least some lesser scaup may remain on the LGL throughout winter and may not necessarily use the same LGL stopover sites each spring.

Based on the favorable results from the first 2 study seasons, we hope to greatly increaseour understanding about migration pathways, chronology, and breeding/staging/wintering ground affinities of lesser and greater scaup using the LGL. To do this, next year we plan to implant satellite transmitters into considerably more female greater scaup that are over-wintering on western LakeOntario. This information, in conjunction with ongoing graduate research conducted by the Long Point Waterfowl and Wetlands Research Fund, will allow us to better evaluate the potential effects that selenium may have on reproduction of greater scaup.