P.TL.02 Testing the efficacy of a floating multicapture trap for invasive Egyptian geese

The Egyptian goose Alopochen aegyptiacus is native to Sub-Saharan Africa and the Nile Valley. It was introduced as ornamental waterfowl in western Europe in the 17th century. Meanwhile, the species is well established in several European countries and waterbirdsurveys show that it is still increasing in numbers and expanding its range. Although this shelduck relative is relatively
small, problems due to overpopulation of this species are comparable to those of larger goose species like greater Canada goose Branta canadensis. The problems include agricultural damage, eutrophication of water bodies and sensitive vegetation types, nuisance through faecal droppings, trampling and overgrazing. As Egyptian goose is capable of using cavities for nesting,
there is also anecdotal evidence for disruption of breeding native species through competition for nesting sites. Although several papers have adressed Egyptian goose as a priority species for management in Europe, very little is known about effective methods for population or local damage control of the species. In Belgium, Egyptian goose are culled through hunting. Also egg destruction is practiced as a management measure. Due to poor documentation of the use of these management measures, little is known about their effectiveness or efficiency. Captures of moulting birds, successful in reducing Canada goose numbers, proved inefficient for trapping Egyptian goose. The birds often do not become completely flightless in July, and tend to dive away before they can be caught. Therefore, we explored innovative options for the control of Egyptian goose and developed a floating multicapture trap with a live decoy bird. This cheap, easy-to-assemble and easy-to-operate device is essentially a Larsen trap consisting of three compartments and modified for floating. The cage can also be put on land in the vicinity of breeding pairs. The floating cages will be tested year-round on 20 locations throughout the project area in a standardised design, investigating monthly differences in trapping success. Cages are set up and focused 5 days per month, starting mid-month, on lakes and ponds, evenly distributed over the project area. Locations were chosen outside a 2km radius of one another in order to avoid interference. Decoy birds were sexed and ringed beforehand and were randomly attributed to locations to exclude a potential confounding effect of sex or quality of the birds. We hypothesize that catching success differs between months. Response variables tested include the number of days to first capture and the total number of birds caught throughout the capture week. During the breeding season, additional traps will be placed in breeding areas close to the nest. For larger, post-breeding concentrations of Egyptian goose (e.g. during the moult period), a specifically designed clap net will be tested. Here, we only report on the set-up and preliminary results of a one-year (2013) field trial with floating multicapture traps. This field trial is carried out within the framework of the Interreg IV-A 2Seas project RINSE (Reducing the Impact of Non-Native Species in Europe, www.rinse-europe.eu ) which seeks to improve awareness of the threats posed by invasive non-native species, and the methods to address them.