. The Canadian field-naturalist. 1989 Notes 395. Figure 1. Map of Kent Island, Bay of Fundy, New Brunswick. Stippling indicates areas covered by the census. nesting in raspberry, vegetational succession does not seem likely to have caused a decline of this magnitude. Human predation has occurred for many years (C. Huntington, personal communication). During the last two weekends in May and the first two weekends in June, between 4 and 20 "eggers" visited the colony. Although my presence reduced their area of activity, their actions appeared to have significantly affected the gulls. T
. The Canadian field-naturalist. 1989 Notes 395. Figure 1. Map of Kent Island, Bay of Fundy, New Brunswick. Stippling indicates areas covered by the census. nesting in raspberry, vegetational succession does not seem likely to have caused a decline of this magnitude. Human predation has occurred for many years (C. Huntington, personal communication). During the last two weekends in May and the first two weekends in June, between 4 and 20 "eggers" visited the colony. Although my presence reduced their area of activity, their actions appeared to have significantly affected the gulls. The eggers arrived at approximately 1300 h, and in some cases did not depart until 1800 h. While in the colony the "eggers" travelled in loose groups, often displacing approximately 50 gulls at a time. Complete as well as partial clutches were removed. The actual number of eggs taken on any one visit was not quantified directly, but each visitor carried either a one-gallon or a five-gallon pail. Thus, a rough estimate of the total number of eggs taken during a single day would be between 50 and 100 eggs. Some "eggers" were also observed destroying eggs indiscriminately. Such disturbances likely influenced reproduc- tive success (through cannibalism and abandon- ment). The removal of complete or partial clutches released pairs from incubation or brooding duties, and hence temporarily increased the number of potential cannibals in the colony (see Paynter 1949; personal observation). Kadlec and Drury (1968) found that the degree to which reproductive success was adversely affected was directly proportional to the proportion of the colony disturbed and the duration of the disturbance. Such large-scale disturbances have been postu- lated as the cause of colony desertions elsewhere (Buckley and Buckley 1977 in Erwin et al. 1981). The decline of the colony may at least be in part, therefore, due to "egging" by local residents. The "egging" is for
Size: 1241px × 2014px
Photo credit: © Book Worm / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookauthorottawafi, bookcentury1900, bookdecade1910, bookyear1919
