Original Article Canada Goose Nest Survival at Rural Wetlands in North-central Iowa BRENNA N. NESS, 1,2 Department of Natural Resource Ecology and Management, Iowa State University, 339 Science Hall II, Ames, IA 50011, USA ROBERT W. KLAVER, U.S. Geological Survey, Iowa Cooperative Fish and Wildlife Research Unit, Iowa State University, 339 Science Hall II, Ames, IA 50011, USA ABSTRACT The last comprehensive nest survival study of the breeding giant Canada goose (Branta canadensis maxima) population in Iowa, USA, was conducted >30 years ago during a period of population recovery, during which available nesting habitat consisted primarily of artificial nest structures. Currently, Iowa’s resident goose population is stable and nests in a variety of habitats. We analyzed the effects of available habitat on nest survival and how nest survival rates compared with those of the expanding goose population studied previously to better understand how to maintain a sustainable Canada goose population in Iowa. We documented Canada goose nest survival at rural wetland sites in north-central Iowa. We monitored 121 nests in 2013 and 149 nests in 2014 at 5 Wildlife Management Areas (WMAs) with various nesting habitats, including islands, muskrat (Ondatra zibethicus) houses, and elevated nest structures. We estimated daily nest-survival rate using the nest survival model in Program MARK. Survival was influenced by year, site, stage, presence of a camera, nest age, and an interaction between nest age and stage. Nest success rates for the 28-day incubation period by site and year combination ranged from 0.10 to 0.84. Nest survival was greatest at sites with nest structures (b ¼ 17.34). Nest survival was negatively affected by lowered water levels at Rice Lake WMA (2013 b ¼0.77, nest age b ¼0.07). Timing of water-level drawdowns for shallow lake restorations may influence nest survival rates. Published 2016. This article is a U.S. Government work and is in the public domain in the USA. KEY WORDS Branta canadensis maxima, giant Canada goose, habitat, Iowa, nest survival, Program MARK, rural. The giant Canada goose (Branta canadensis maxima) was extirpated from most of its range in the early 1900s as a result of overharvest of the birds and their eggs, as well as habitat destruction through wetland drainage (Schrader 1955, Bishop 1978, Hanson 1997). Restoration efforts in Iowa, USA, were initiated in 1964 by confining flocks of flightless geese to 15 wetland areas across the state (Bishop and Howing 1972, Zenner and LaGrange 1998a). These efforts were very successful and by the end of the century, giant Canada geese (hereafter, Canada geese) were nesting in every county in Iowa. The first reintroduction sites were in north-central Iowa (Iowa DNR 2002), which lies within the southernmost portion of the Prairie Pothole Region (PPR). The PPR is characterized by shallow lakes and marshes that serve as highly productive waterfowl nesting habitat (Shaw and Fredine 1956). Restored goose populations flourished and geese now nest there in high densities (Zenner and LaGrange 1998b). Canada goose reintroduction sites were rural wetlands that provided ideal nesting habitats (Iowa DNR 2002). Iowa’s Canada goose population is currently stable, but most reintroduction sites remain closed to Canada goose hunting (Iowa DNR 2002). The goal of goose management in Iowa is to maintain a sustainable population for maximum recreational opportuni- ties while keeping goose numbers at socially acceptable levels (Iowa DNR 2002). Rural wetland sites in Iowa’s PPR provide a variety of nesting habitats for Canada geese. Multiple lakes and marshes contain islands; muskrat (Ondatra zibethicus) activity in marshes produces additional nest sites; and the Iowa Dept. of Natural Resources (DNR) has erected nest structures for geese on some areas. Islands provide refuge from mammalian predators, but host limited numbers of geese because of the birds’ territorial behavior (Vermeer 1970, Ewaschuk and Boag 1972, Giroux 1981). Muskrat houses and cattail (Typha spp.) mounds provide isolated nest sites generally safe from predators, but can be susceptible to flooding. Nest structures are highly secure nest sites, but require upkeep to remain usable (Mackey et al. 1988, Ball 1990, Zenner et al. 1992). We selected 5 rural wetland sites to monitor Canada goose nest survival in Iowa’s PPR during the 2013 and 2014 nesting seasons. Drought conditions in 2012 provided an opportu- nity to renovate Rice Lake, one of our selected study sites. These conditions prompted the Iowa DNR to lower Rice Received: 12 June 2015; Accepted: 5 September 2016 Published: 25 November 2016 1 E-mail: brennatowery@gmail.com 2 Present address: 315 Main Street, Odessa, DE 19730, USA Wildlife Society Bulletin 40(4):705–713; 2016; DOI: 10.1002/wsb.716 Ness and Klaver  Canada Goose Nest Survival in Iowa 705