Annual and large-scale variation in breeding output of Greylag geeseAnser anserin Iceland

Capsule Large-scale variation in breeding output of Greylag geese Anser anser is negligible across Iceland but detectable variation is likely related to spring temperature.Aims To identify large-scale spatial and annual variation in breeding parameters to support sustainable utilization and conservation of Greylag geese that are a quarry species in Iceland and the UK.Methods In 2012 and 2013, a total of 360 Greylag nests were visited across Iceland and timing of breeding, egg sizes and clutch sizes were measured. In addition, 888 Greylag families were surveyed in the same period to estimate large-scale variation in brood sizes.Results Timing of nest initiation varied significantly between parts of the country and nesting started on average on 30 April in West and South Iceland, but considerably later in cooler parts of Iceland, North Iceland (10 May) and East Iceland (20 May). In 2012, clutch sizes were similar between areas but in 2013, East Iceland had a smaller mean clutch size than South and West Icel...