Introduction

Return to Conservation Biology Research on Birds

Wires, L.R., K.V. Haws, and F.J. Cuthbert. 2005. The double-crested cormorant and American white pelican in Minnesota: a statewide status assessment. Final report submitted to the Nongame Wildlife Program. 28 pp.

Introduction:

In North America, numbers of the federally protected fish-eating bird species, Double-crested Cormorant (Phalacrocorax auritus) (DCCO) and American White Pelican (Pelecanus erythrorhynchos) (AWPE), have increased dramatically over the last 20-25 years in many portions of their ranges (Wires et al. 2001; Evans and Knopf 1993). In Minnesota, data collected from the 1960s to present suggest that both species have increased since the 1960s (DNR Natural Heritage Program Data Base). As these species have become more abundant, citizens in some regions of Minnesota have expressed concern over potential impacts on aquaculture and sport fishing (Wires et al. 2003; K.V. Haws, pers. comm., S. Mortensen, pers. comm.). Both species are perceived to affect recreation opportunities and local business economies. Despite public interest in management of these species and the inclusion of Minnesota in the Depredation Order (established by U.S. Fish and Wildlife Service in 1998 to allow individual fish farmers to kill unlimited numbers of cormorants at their ponds), little is known about current distribution and abundance of cormorants or pelicans in Minnesota. Both species occur in the state as migrants and breeders but no complete statewide census for either species has ever been undertaken in one year despite the fact that numbers are thought to be increasing.

In 2003, a federal EIS was issued and a Public Resource Depredation Order established for the Double-crested Cormorant (USFWS 2003 a,b). The Public Resource Depredation Order allows federal, state and tribal agencies to √?¬?√?¬?take√?¬?√?¬? (kill) Double-crested Cormorants believed to be impacting public resources on public and private (with owner permission) lands without acquiring a permit. Because control efforts for DCCOs in MN are under consideration, the MN DNR needs accurate and current data on the number of breeding pairs and location of colony sites to monitor effects on Minnesota√?¬?√?¬?s DCCO population if control is undertaken. Although there is currently no management plan for the American White Pelican, and this species is listed as Special Concern in MN, concern about impacts related to its consumption of fish have been documented (Wires and Cuthbert 2003). Because this species is highly sensitive to human disturbance and known to commonly occur with DCCOs in Minnesota, control efforts for DCCOs could significantly impact pelicans. Given the fish-eating behavior of pelicans, this species is likely to be targeted by local citizens for illegal control efforts and may become a management issue in the future. Thus, the MN DNR also needs to establish baseline information on distribution and numbers for this species.

In addition to information on cormorants and pelicans, data are also needed on other species of colonial waterbirds (e.g., herons, gulls, terns) that co-occur with DCCOs at their breeding colonies. These data will help the MN DNR make informed decisions about management and conservation on a site basis and monitor impacts of DCCO control on other species.

Project Goals: The primary goal of this project was to obtain statewide breeding population estimates for the American White Pelican and Double-crested Cormorant in Minnesota, using data recorded from detailed ground surveys of all reported pelican and cormorant colonies in 2004, and aerial surveys of the primary pelican colony (e.g. Marsh Lake) in 2004 and 2005. The project also has two secondary goals: a) verify current breeding locations of pelicans and cormorants, and enter this information into the Natural Heritage Data Base and b) document presence and/or obtain estimates of nests of co-occurring colonial waterbird species (e.g. gulls, terns, herons) at all active cormorant colonies, because cormorant management activities, if undertaken, are likely to impact these other species.

Funding: This project was funded with a $32,720.00 grant to the University, and a $23,464.00 allocation to the Nongame Program. In 2004, these funds covered the hiring of a part time project coordinator, two field technicians, travel expenses and equipment. The grant included Federal funds and required a state match. The total cost of this project was $56,464.00.

Full document (640 KB) This is a PDF file. You will need Adobe Acrobat Reader to download it.