Conservation and Management

Breeds in proximity to human habitation. Intentional or unintentional reductions of breeding populations usually local and short-term (Buckley and Buckley 1984, Blodget 1988). Actively hunted for eggs and feathers during nineteenth century, now protected from both forms of exploitation. Exploitation all but stopped in U.S. but continues in Canada. Oil pollution, pesticide contamination, destruction of food sources through overfishing, and deliberate control measures are human activities most likely to affect populations (Graham 1975, Blodget 1988, Fox 1990).

Herring Gull reached very low numbers during nineteenth century, was considered rare by Audubon. Increase in numbers after turn of century should be viewed in large part as recovery from persecution, especially since we have no good estimates of numbers prior to human impact (Graham 1975). Increased gull population sizes in New England and Great Lakes traditionally attributed to increased food availability from feeding on human refuse, including bycatch and offal from fishing operations (Kadlec and Drury 1968, Hunt 1972, Pons 1992). Actual situation more complex; rapid increase from 1930s through 1960s resulted from combination of factors: (1) serious protection of birds and growth of conservation movement in U.S. (Dunlap 1988), (2) increased fishing activity which (a) generated considerable waste available as food and (b) reduced competition for small to medium-sized fish preferred by gulls by reducing numbers of large fish, e.g., cod, salmon, (3) increasing human population generated large amounts of garbage and proliferation of garbage dumps, which served as foraging areas, especially important in increasing overwinter survival of juveniles, and (4) near extirpation of cetacean and pinniped populations in many areas reduced competition for small fishes (capelin, sandlance [Ammodytes sp.]) and pelagic invertebrates (krill, copepods). Herring Gull numbers leveled off in mid-1970s and 1980s as dumps closed and changed, and overfishing destroyed fish stocks; may actually be declining in several areas at present, e.g., Newfoundland, New Brunswick, and Maine.

Numerous studies of use of refuse from dumps (garbage, distinguished from fisheries wastes) as food by breeding Herring Gulls do not support idea that garbage dumps were major force driving population increases. In Holland, an increase in garbage as food has been related to decline in Herring Gull breeding success (Noordhuis and Spaans 1992). In Newfoundland and Massachusetts, gulls feeding garbage to chicks showed lower chick growth and survival (Pierotti and Annett 1987, 1990, 1991). In Great Lakes, successful breeding pairs fed primarily on fish; although many gulls were observed on dumps, most were loafing rather than feeding (Belant et al. 1993). Fisheries waste (bycatch and fish offal) much higher in quality as food (Pierotti and Annett 1987). Much confusion over role of “refuse” as a food source resulted from investigators failing to distinguish clearly between fishery-generated wastes and garbage from dumps when using term refuse (e.g., Drury and Nisbet 1972, Hunt 1972). Future studies should clearly distinguish between fishery waste and garbage, as these diet categories have different implications for gull nutrition.

Gull culls, egg smashing, and spraying with oil carried out by state agencies and private individuals to provide greater nesting opportunities for other seabirds, including terns, puffins, even other gulls (Drury and Nisbet 1972, Graham 1975, Blodget 1988, Alpers 1991). Efforts ineffective on large scale, although small-scale efforts have been successful in eliminating gulls from small colonies (Blodget 1988, Alpers 1991). In Witless Bay, Newfoundland, Herring Gull supposedly reduced breeding success of Atlantic Puffin (Fratercula arctica) through egg and chick predation, and piracy. Cull suggested as solution (Nettleship 1972). Subsequent work showed Herring Gull did not eat puffin eggs and chicks, except when puffins were disturbed by humans or ravens. Piracy on puffins primarily occurred in areas of low puffin density and in years when puffins had low breeding success because of reduced food availability (Pierotti 1983, Rice 1985). Culling Herring Gull on Isle of May, United Kingdom, resulted in 70% decline in number of breeding gulls but only 10% decline in area of island occupied (Coulson 1991). Primary effect was therefore increase in average Herring Gull internest distance; did not make more habitat available for other species.