Nest Protection From Agriculture and Predation to Improve Nest and Chick Survival of the Northern Lapwing Vanellus Vanellus in Swiss Farmland

27 Mar Nest Protection From Agriculture and Predation to Improve Nest and Chick Survival of the Northern Lapwing Vanellus Vanellus in Swiss Farmland

View Original

Abstract

English Abstract

The plain of Wauwil in central Switzerland is a traditional breeding area of the Lapwing. In 1880, the number of breeding pairs was estimated at 100. It dropped to very low numbers by the 1930s, but grew to 40–60 in the 1950s. As in other parts of Switzerland, numbers collapsed in the eighties to a low of merely 10 pairs in 1990–2003. In 2005–2009, numbers fluctuated between 17 and 27 pairs, accounting for a quarter of the Swiss population. In 2009 the plain of Wauwil and its nationally significant Lapwing breeding sites were included in the Federal Inventory of waterbird reserves of national importance. Since 2005, the Swiss Ornithological Institute has been evaluating measures to protect Lapwing broods from the impacts of agriculture and predation. All nests were marked in the field and in close cooperation with the farmers nests and eggs were secured during agricultural work. In addition, most fields with Lapwing nests were surrounded by electric fences to keep out ground predators. As a result of these combined measures, hatching rate climbed to 68.7 %. Of 129 nests protected by an electric fence, 74.4 % hatched, 19.4 % were abandoned, mostly due to farming, and 6.2 % were predated. In 24 unprotected nests, 29.2 % hatched, 4.2 % were deserted and 66.7 % were predated. From hatching to fledging 35–40 days later, merely 0.4 young survived per pair and year in 2005–2007. According to analyses of British ringing recoveries, a fledging rate of 0.7 is necessary for population stability. As documented by radio-telemetry of 78 and 81 chicks tagged in 2006 and 2007, most disappeared during the night and outside the fences and were most likely predated. To extend protection from predation to the flightless chicks, fences were set up also on fields covered by foraging young. To reduce farming impact on Lapwing nests, cultivation was postponed to the end of May on two fields remaining fallow after the harvest the previous year. By this date, 13 of 17 clutches had hatched and the chicks were at least 2 weeks old. Thanks to these additional measures, 0.78 and 1.26 young fledged per pair in 2008 and 2009, respectively. The mean fledging rate in 2005 to 2009, 0.65 ± 0.46, was very close to the rate required to maintain the population. Hence, nest and chick protection substantially reduce the impact of farming and predation on Lapwing breeding success. For the future, we aim to improve the efficiency of a management plan by optimising expense and revenue of the measures taken.