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Home | Bird Damage | Waterbirds Waterbirds
Canada GeeseHere a goose, there a goose, everywhere another goose. In the early 1960s, federal and state wildlife agencies worked to increase low Canada goose populations in North America. They were so successful that numbers increased from just under 250,000 birds in 1970 to more than 2 million in 1996. Now, many of the growing numbers of geese have settled in urban and suburban areas and are considered pests. While gaggles of geese can elicit giggles of delight from both children and adults, the numerous problems caused by these giant honkers are no laughing matter. You can find geese roaming golf courses, soccer and football fields, parks, bikeways and almost anywhere else lush, green grass is available. But the birds kill the grass by overfeeding and trampling shoots. Fecal deposits in ponds, lakes and other waterways degrade water quality and promote algal blooms. Goose droppings may even affect human health. They harbor strains of E. coli, some of which may cause disease in humans. Geese may affect human safety as well. Aggressive geese will chase and peck individuals that disturb them. Flying geese, sucked into engines or crashing through windshields, can cause airplane crashes. 
HeronsThe great blue heron, very common at northeastern aquaculture facilities, is considered to inflict the most damage to the industry. The bird forages at aquaculture facilities primarily at dawn and dusk. At trout-rearing facilities, a heron can consume 2.2 live trout per hour. The average trout prey is 9 inches long, but may be up to14 inches. At warm-water facilities, great blue herons consume smaller, but proportionally more, fish. At these facilities, herons are thought to consume about 0.5 pound of fish per day. The black-crowned night heron can also be found at northeastern aquaculture facilities but is more common at western aquaculture facilities. This heron usually starts feeding at dusk and may continue to feed through the night, consuming, on average,1.2 live trout per hour apiece. The green-backed heron is the only other commonly occurring heron species that frequents northeastern aquaculture facilities. It is believed that this heron eats about 3 live fish per hour. 
PelicansAmerican white pelicans, in flocks of 1,500 to 2,000 birds are common on catfish farms and adjacent flooded fields in the Mississippi Delta. The large size of this bird, and the resultant higher food requirements, as well as the ability to forage at night, make this bird a potentially great threat to catfish producers (Tobin 1998). CormorantsDouble-crested cormorant predation on catfish farms has been well documented. As the industry has grown, so too have cormorant breeding populations. From 1995 to 1998, the number of cormorants spending the winter in the catfish production region of Mississippi has more than doubled and now exceeds 60,000 birds. Also, in 1998, cormorants were first discovered breeding in Mississippi and Arkansas for the first time in decades. Breeding populations in the Great Lakes region will also likely increase, resulting in more habitat destruction, competition with other waterbirds, and competition with sport fishermen and fisherwomen (Glahn et al. 2000). 
DucksMigrant waterfowl can cause damage in northern and central North American crops. In the spring, they can graze and trample such crops as soybeans, sunflowers and cereal grains. The mallard is a common species of waterfowl that frequents northeastern aquaculture facilities. However, the predation problems it poses occur in isolated situations. Where predation situations do occur, mallards have learned to feed in trout raceways stocked with high densities of smaller fish. In addition to mallards, mergansers, scoters, black ducks, and eiders can cause problems at aquaculture facilities by feeding on fingerling fish. The belted kingfisher is seen at many northeastern aquaculture facilities throughout the year. However, the typically low densities at which it occurs and the smaller fish it consumes lessen its potential impact on the industry. The belted kingfisher forages throughout the day by plunging directly into the water to capture fish near the surface and then rapidly flies off with its prey. It consumes fish at a rate of almost 2 fish per hour. ReferencesGLAHN, J. F., M. E. TOBIN, AND B. F. BLACKWELL. 2000. A science-based initiative to manage double-crested cormorant damage to southern aquaculture. United States Department of Agriculture APHIS 11-55-010 TOBIN, M. E. 1998. Research and management of bird depredations at catfish farms. Pages 67-70 in Barker, R. O. and Crabb, A. C., editors. Eighteenth Vertebrate Pest Conference (March 2-5, 1998, Costa Mesa, California). University of California at Davis, Davis, California. TOBIN, M. E., technical coordinator. 1999.Symposium on double-crested cormorants: population status and management issues in the Midwest (Dec. 9, 1997, Milwaukee, WI) USDA APHIS Technical Bulletin No. 1879. Canada Geese Links http://www.rcre.rutgers.edu/pubs/publication.asp?pid=FS1025(New Jersey) Cormorants Linkhttp://www.dec.state.ny.us/website/dfwmr/cormorant/index.html (New York) |
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Content: Laurie Paulik Last updated:
02/05/08 |
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