The Wildlife Services-National Wildlife Research Center’s Mississippi Field Station working in conjunction with Mississippi State University conducted a study to test the effectiveness of several commercially available physical bird deterrents available on the open market to reduce roosting time on floating oyster cages. Our hypothesis was that reducing birds loafing time on floating oyster cages would reduce the potential for feces to increase coliform counts in water and oysters which could lead to the closure of oyster farms due to excessive bacterial counts.
Fifteen Double-crested cormorants (DCCO) were captured in night roosts in Mississippi or Alabama using a customized capture boat, flood lights, and dip nets and then transported to the National Wildlife Research Center Mississippi Field Station avian test facility. Five DCCO were released into each of three aviary enclosures containing a 0.1-acre pond stocked with catfish fingerlings.
Each pond contained a floating oyster cage to which one of 6 deterrents was applied and was monitored by 3 motion activated cameras that recorded DCCO positions and movements. After capture DCCO were given 1.5 weeks to acclimate and one additional week of a control period. After that each week consisted of 5 days of a deterrent and 2 days of rest with no deterrent. Pond treatments were randomly reassigned so that each week a different pond was the control pond and the treatment ponds each had a new deterrent method. Deterrents were removed from all oyster cages and ponds for two additional weeks with no deterrent methods to see how DCCO would react.
Deterrent methods that were tested included: Float mounted triangle, Bird B Gone Spinning Bird Deterrent®, Scarem Kite®, Zip ties around floats, Gullsweep Bird and Seagull Deterrent®, and Bird Spikes for Bird, Cat, Squirrel, Racoon Animals Repellent®. Data collected by deterrent method included 1) number of times an individual DCCO successfully landed on floats, 2) number of individual DCCO’s on a float, 3) amount of time individual DCCO spent on float, 4) number of times an individual DCCO unsuccessfully attempted to land on floats. Over 184,000 photos were reviewed. Data analysis from this study is underway with preliminary results indicating a variation in the effectiveness depending on the deterrent method tested.