Use of Grassland and Field Selection by Brent Geese Branta bernicla

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Abstract
Around Scolt Head Island, north Norfolk, 43.7%, 57.7% and 65.5% of the cumulative total number of observations of brent geese were made on grass fields during 1986-87, 1987-88 and 1988-89, respectively. In the first year more time was spent on arable fields compared with the following years. On average, 74% of the day (dawn-dusk) was spent on grass or arable fields during January-March. The time of arrival of geese on the fields in the morning was related to the state of the tide. Arrival was later if high tide occurred around dawn and earlier if low tide occurred around dawn. The geese left grass fields 11 .+-. 22 min before sunset to roost. Individual geese visited 3.9 .+-. 1.6 fields (mean size, c. 5 ha) day-1 spending 1.7 h in each. Foraging was the main activity, comprising 71% of the time-activity budget. Daytime flights between the roost and grassland feeding sites were 8.2 .+-. 2.4 km long. Home ranges were 6.1 .+-. 2.1 km2. Grazing intensity (estimated from dropping densities) averaged 42.8 droppings m-2 for three of the most intensively used fields, representing 2.4 h of grazing m-2. Therefore, it would require 500 m2 to support one goose from November to mid March. Fields with a high percentage of live grass were selected by geese, perhaps on the basis of their colour. Once selected, those fields with the shortest grass (c. 5 cm) and fewest thistles were more intensively used. Grass fields could be used as alternative feeding areas to alleviate grazing on cereals. It is recommended that such areas should (i) be located on the coast close to the roost site of each population of geese, (ii) be split into several sites so that the geese can go to another site if disturbed, and (iii) total 50 ha for every 1000 geese. The sward would need to be maintained in a suitable condition for the geese by appropriate management.
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