Date of Award

January 2012

Document Type

Thesis

Degree Name

Master of Science (MS)

Department

Biology

First Advisor

Brett J. Goodwin

Second Advisor

Katherine R. Mehl

Abstract

The Prairie Pothole Region (PPR) is the most important breeding habitat for North American ducks. However, much of the PPR is suitable for large-scale wind energy development and conflicts for waterfowl populations may occur if wind energy alters habitat in a way that reduces survival or productivity. Adult survival of breeding female ducks has a disproportionately large effect on population growth. Thus, populations might be particularly sensitive to increased mortality in this cohort because of direct collisions with wind turbines. Additionally, large home ranges are energetically taxing. If females avoid resources near wind turbines during breeding season activities, females may allocate less energy to reproduction and more energy to visiting distant foraging sites. Thus, wind energy development may indirectly impact duck production. Lastly, wind energy may be a source of indirect habitat loss if females avoid wind turbines when selecting nest sites. To assess these direct and indirect impacts of wind energy on breeding waterfowl, we radio-marked and monitored female mallards (Anas platyrhynchos) and blue-winged teal (A. discors) during the 2009 and 2010 breeding seasons at the Tatanka Wind Farm (TWF) near Kulm, North Dakota and an adjacent reference site without wind turbines (REF).

A single radio-marked female mallard and no blue-winged teal collided with wind turbines. Most mortalities, irrespective of species and site, were caused by predators (78.3%; 36/46). For mallards, the best-approximating survival model indicated that

breeding season survival depended on year and site such that survival in 2009 was high at TWF (S ̂ = 0.90, 95% CI = 0.61 - 0.98) relative to survival at REF (S ̂ = 0.83, 95% CI = 0.48 - 0.95) but survival in 2010 was low at TWF (S ̂ = 0.62, 95% CI = 0.31 - 0.80) relative to survival at REF (S ̂ = 0.84, 95% CI = 0.57 - 0.94). The most competitive model for blue-winged teal including the effect of wind turbines indicated that breeding season survival at TWF (S ̂ = 0.71, 95% CI = 0.57 - 0.81) was lower than survival at REF (S ̂ = 0.81, 95% CI = 0.65 - 0.90). There was a positive association between the presence of wind turbines and home range size for female mallards (â ̂ = 0.0154, SE = 0.0711) and a negative association between the presence of wind turbines and home range size for blue-winged teal (â ̂ = -0.0892, SE = 0.1650), but we obtained no support for this effect on mallard home range size and moderate support for this effect on blue-winged teal home range size. Female mallards and blue-winged teal did not appear to avoid wind turbines when selecting nest sites. Our results suggest that females breeding in wind-developed landscapes rarely collide with wind turbines and probably do not avoid wind turbines during breeding season activities. Thus, waterfowl management strategies in the PPR that include acquiring wetland and grassland easements in wind-developed landscapes may be appropriate. However, differences in survival between TWF and REF for both species may reflect potential indirect effects of wind development activity on female survival and further study may be required given the scope and scale of projected wind energy development in the PPR.

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