Changes in the proportion of young birds in the hunting bag of Eurasian wigeon : long-term decline, but no association with climate

• Published in: European Journal of Wildlife Research
• Main Authors: Pöysa, Hannu, Vaananen, Veli-Matti
• Other Authors: Department of Forest Sciences, Wetland Ecology Group, Forest Ecology and Management
• Format: Article in Journal/Newspaper
• Language: English
• Published: Springer 2020
• Subjects: Age ratio; Breeding success; Climate; Hunting bag; Temperature; NORTH-ATLANTIC OSCILLATION; ANAS-PENELOPE; AUTUMN MIGRATION; AGE RATIOS; WATERBIRDS; PRESSURE; NUMBERS; GEESE; VARIABILITY; 1181 Ecology; evolutionary biology; North Atlantic; North Atlantic oscillation
• Online Access: http://hdl.handle.net/10138/309885

The proportion of first-year birds in annual wing samples provided by hunters has been used as a measure of breeding success in waterfowl. The proportion of first-year birds in the wing samples of Eurasian wigeon (Mareca penelope) from Denmark and the UK shows a long-term decline, probably reflecting a decrease in breeding success. However, previous studies report conflicting results in the relationship between variation in the proportion of first-year birds and variation in climatic conditions. We used wing data of hunter-shot Eurasian wigeon from Finland to study whether the proportion of first-year birds shows a similar long-term decline and whether between-year variation in the proportion of young is associated with variation in climatic conditions. We found a long-term decline in the proportion of first-year birds. The proportion of young also varied considerably between years, but this variation was not associated with weather or the climatic variables considered for the breeding and wintering periods. More research is needed concerning factors that affect long-term changes and annual variation in the proportion of young in the hunting bag and on the suitability of this index to measure productivity in ducks. Peer reviewed