Double-crested Cormorant (Phalacrocmax auritus) numbers in the Great Lakes of North America have increased dramatically during the past three decades. Current concerns include negative effects of cormorants on aquatic food webs, destruction of nesting habitat and competition with other avian species and odors due to feces. Control of cormorant nesting and roosting has been variably successful and sometimes involves lethal force and/or loud devices. These approaches may be unsuitable in some settings, such as parks or residential areas. A large group of cormorants (up to 2,000 individuals) has used Farr Island, a small island near houses on the North Shore of Hamilton Harbour at the west end of Lake Ontario, Canada, as a post-breeding roosting area. The concentration of birds has resulted in complaints regarding odors from the island. In an attempt to alleviate the strong odor and to examine options to limit cormorant nest site competition with other species, a tethered Steppe Eagle (Aquila nipalensis) was placed on the roost island for twelve days from 9 to 21 September 2003. The eagle was effective at causing roosting cormorants to avoid the island, apparently causing many to move their roost site a short distance to another island nearby. Complete cormorant displacement lasted at least four days beyond the period of eagle presence on the island. Using a tethered large raptor appears to be an effective non-lethal tool for local displacement of roosting Double-crested Cormorants.
You have requested a machine translation of selected content from our databases. This functionality is provided solely for your convenience and is in no way intended to replace human translation. Neither BioOne nor the owners and publishers of the content make, and they explicitly disclaim, any express or implied representations or warranties of any kind, including, without limitation, representations and warranties as to the functionality of the translation feature or the accuracy or completeness of the translations.
Translations are not retained in our system. Your use of this feature and the translations is subject to all use restrictions contained in the Terms and Conditions of Use of the BioOne website.
Vol. 35 • No. sp1