An Evaluation of Winter Roost Harassment for Dispersing Double-Crested Cormorants Away from Catfish Production Areas in Mississippi

• Published in: Wildlife Society bulletin 1998-10, Vol.26 (3), p.584-591
• Main Authors: Mott, Donald F., Glahn, James F., Smith, Patrick L., Reinhold, David S., Bruce, Kevin J., Sloan, Charles A.
• Format: Article
• Language: English
• Subjects: Birds; Capital costs; Catfish; Catfish farms; Fish production; Harassment; Ponds; Predation; Pyrotechnics; River deltas; Techniques; Waterfowl; Wildlife management
• ISSN: 0091-7648; 1938-5463

We evaluated the effectiveness of harassing wintering double-crested cormorants (Phalacrocorax auritus) at their night roost sites over a 3-winter period as a means of reducing their impact on the catfish industry in the Delta region of Mississippi. Cormorants were dispersed from night roost sites by persons firing pyrotechnics at the birds in the roost and at those flying towards the roost for a 2-hour period before sunset. Numbers of cormorants at intensely harassed roost sites were greatly reduced in comparison with numbers at roosts that were not harassed or less intensely harassed. Numbers of cormorants surveyed on or near catfish ponds in March also were reduced by ≥70% during years of extensive harassment compared with numbers surveyed the year before harassment. Catfish producers within an area of intensive roost harassment perceived a reduction in problems with cormorant predation during the years of harassment as compared to previous years. Producers within this roost harassment area also reported spending less money on cormorant control on their farms. Those outside the roost-harassment area reported spending more.