Black Duck Joint Venture Progress Report September Linking natal and harvest areas of American black ducks using stable isotope analysis

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1 Black Duck Joint Venture Progress Report September 2008 Project Title: Linking natal and harvest areas of American black ducks using stable isotope analysis Principal Investigators: Dr. Scott Petrie, Executive Director Long Point Waterfowl, P.O. Box 160, Port Rowan, Ontario N0E 1M0, (519) ext 208 Norm North, Waterfowl Specialist, Canadian Wildlife Service, Ontario Region, 465 Gideon Dr. PO Box 490 Lambeth Station, London, Ontario N6P 1R1, (519) Keith Hobson, Prairie & Northern Wildlife Research Ctr., Canadian Wildlife Service 115 Perimeter Road Saskatoon, Saskatchewan, S7N 0X4, (306) Paul Ashley, Ecosystem Scientist, Parks Canada, Iqaluit, Nunavut, X0A 0H0, (867) Project Duration: 2006 to 2009 Project Description Effective harvest management of American black ducks (Anas rubripes, hereafter black duck) requires knowledge of the linkages between production areas and their contributions to regional harvest. Acquiring this information is often logistically and financially challenging using traditional methods of population surveys and banding studies and is especially true for a species such as the black duck which has a sparsely populated but extensive breeding range across eastern North America. To determine if some of these challenges could be overcome using stable isotope analysis we sampled specimen feathers from hatch-year (HY) black duck wings submitted to the Canadian

2 2 Wildlife Service species composition survey. Specifically we are investigating whether natal origins and harvest could be linked with sufficient resolution to be useful for harvest management decisions. The use of isotopic markers to determine origins and habitat use may in some circumstances be preferable to traditional methods of identifying production areas and elucidating migratory movements for several reasons. Black duck banding stations for example are for the most part located at the southern edge of present-day black duck breeding range and analysis of band recapture data is potentially biased towards characteristics of individuals found in that spatially discrete segment of the population captured during the pre-season banding period. Even though considerable cost and effort is expended to band black ducks rigorous analysis of movement patterns is limited by the number of band returns, and analysis lags until there are sufficient recaptures and reports. Also, most young-of-the-year birds have fledged and traveled some distance prior to being captured at a banding station (Gustafson 1987), which reduces the usefulness of banding data to provide linkages between production and harvest areas (except those proportionally few birds that have not fledged and are banded as local ). In contrast, a large sample from a single hunting season representative of the harvested population can be collected from specimen wings submitted to species composition surveys. We provide here a progress report of our work linking natal origins of harvested HY birds from Ontario, Quebec, and Maritmies (Newfoundland & Labrador, New Brunswick, Nova Scotia and Prince Edward Island) using feather-bound stable isotope signatures of deuterium (Marra, Hobson, and Holmes 1998, Hobson 1999, Hebert and Wassaner 2005). We further infer the composition of harvested HY birds that fledged

3 3 from a freshwater or marine environment using C13 signatures. We do this because black ducks are known to breed in a variety of freshwater and saltwater habitats (Longcore et al. 2000) and the contribution of birds from these habitats to the harvested population is largely unknown. We also use N15 signatures to determine whether birds fledged from an agricultural or non-agricultural landscape. Lastly, we determine the relationship between harvest date and latitude of origin using deuterium isotope markers that provide a resolution of about 1.5 degrees latitude (Meehan et al. 2001) because timing of migration may potentially expose certain segments of the population to differential harvest rates. Being able to determine the spatial and temporal derivation of HY harvest is another important tool waterfowl managers can use to appropriately regulate the harvest of black ducks. Our objectives are to provide waterfowl managers with a snapshot of geographical origins of black duck harvest across Canada and relate that to observed harvest. Methods Collection of Specimen Wings We collected 200 hatch-year black duck wings from the 2006 Canadian Wildlife Service Species Composition Survey. Samples were obtained from birds harvested in Ontario (n = 36), Quebec (n= 56) and the Maritime provinces (n = 108) to provide a sample representative of the range of birds harvested in Canada. In recent years, about 2000 black duck wings are submitted annually to the survey, providing a sample pool of > 1500 hatch year wings from which we obtained 200 specimens weighted according to the geographical level of harvest. For each sample we pulled the first primary (adjacent

4 4 to the first secondary) and stored it in a paper envelope. We recorded date and location of harvest from information supplied by the hunter. We determined age and sex using methods developed by Carney (1992). Samples were sent to the University of Saskatchewan stable isotope lab for analysis. Preliminary Results Location of harvested birds derived from information supplied by hunters (Figure 1) indicates that birds are harvested predominantly at the southern portion of their Canadian range and some birds harvested and submitted by Canadian hunters were harvested in the northern US. Figure 1. Location of harvest hatch year black ducks, Isotopic signatures

5 5 Isotopic signatures for deuterium, C13 and N15 are complete. We used a bin approach to pool deuterium signatures (Figure 2). Some preliminary analysis of this work indicate that: 1) the very northern part of black duck breeding range is an important production area for birds harvested in Quebec but almost inconsequential to the Ontario harvest. 2) the near-north isoband, north of Lake Superior and south of James Bay produces the largest proportion of harvested birds for both Ontario and Quebec, and intermediate for the Maritimes. 3) the mid latitude portion of the breeding range is an important production area for all three harvest areas. 4) no birds harvested in Ontario and few birds harvested in Quebec originated from the southern portion of the range, whereas about 30% of the birds harvested in the Maritimes originated south of the Canadian border.

6 6 60 Percent Harvested in Ontario Harvested in Quebec Harvested in Maritime Provinces to to -74 > -75 Feather Deuterium (per mil) Figure 2. Percent of harvested Black Duck samples with inferred natal originsin geographic ranges of stable deuterium concentrations (see map).

7 7 Figure 3. Deuterium Gradient Across North America Our last objective, to determine the relationship between harvest date and latitude of origin exhibited no significant trend. Project Status Stable isotope signatures of C13 and N15 to determine aquatic and terrestrial use have been completed and are being interpreted. A probability surface that propagates the error associated with the regression of feather versus precipitation dd is being produced. Final results will be presented at the North American Duck Symposium in Toronto, August 2009.

8 8 Budget and Project Funding Sources BUDGET (US Dollars) Funding Sources --- Indicate in-kind contributions in italics Expense Category BDJV CWS CWS LPWWRF TOTAL PNR Personnel 4,800 2,400 3,600 10,800 Technician salaries and 8,000 7,000 analytical lab work GIS technician 2,000 2,500 Production/Disbursement of 3,000 3,000 papers/posters etc. Overhead TOTALS BY FUNDING SOURCE 10,000 4,800 2,400 6,600 23,800 No additional funding is requested or anticipated. Literature Cited Ashley, E.P.2005 Wing moult and age determination of American black ducks, MSc. Thesis Dept. Biology, Univ. Western Ontario. London Ontario. 95 pp. Blandin, W. W Population characteristics and simulation: modeling of Black Ducks. U.S. Fish and Wildlife Service Technical Report Series No. 11. Conroy, M. W. Miller, and J. E. Hines Review of population factors and synthetic population model for American black ducks. Wildlife Monographs No. 150., C. J. Fonnesbeck, and N. L. Zimpfer Adaptive Harvest Management of multiple stocks of American black ducks. The Wildlife Society 10th Annual Conference. The Wildlife Society, Burlington, Vermont 6-10 September Environment Canada The Science and the Environment Biulletin. May/June Hobson, K. A Stable-carbon and nitrogen isotope ratios of songbird feathers grown in two terrestrial biomes: implications for evaluating trophic relationships and breeding origins. Condor 101:

9 9 Hobson, K. A., and L. I. Wassenaar Linking breeding and wintering grounds of neotropical migrant songbirds using stable hydrogen isotopic analysis of feathers. Oecologia 109: Krementz, D. G., M. J. Conroy, J. E. Hines, and H. F. Percival Sources of variation in survival and recovery rates of American black ducks. Journal of Wildlife Management 51: ,,, and The effects of hunting on survival rates of American black ducks. Journal of Wildlife Management 52: Longcore, J.R., D.G. McAuley, G.R. Hepp, and J.M. Rhymer. 2000a. American black duck. The Birds of North America Series. A. Poole and F. Gill eds. No. 481, 30pp. Pendleton, G. W. and J. R. Sauer Black duck population units as determined by patterns of band recovery. Pages in D. R. McCullough and R. H. Barrett, Editors. Wildlife 2001: populations. Elsevies Applied Science, New York, New York, USA. USGS How stable isotopes work. Fort Collins Science Centre online. ywork.asp Wassenaar, L. I., and K. A. Hobson Stable-carbon and hydrogen isotope ratios reveal breeding origins of red-winged blackbirds. Ecological Applications 10: Zimpfer, N.L Estimating movement and production rates in American black ducks. M.Sc. Thesis. University of Georgia, Athens, Georgia. 117 pp.