Use of agricultural fields by Ruffs staging in southwest Friesland in 2003–2013

• Published in: Ardea
• Main Authors: Schmaltz, L.E., Vega, M.L., Verkuil, Y.I., Hooijmeijer, C.E.W., Piersma, T.
• Format: Article in Journal/Newspaper
• Language: English
• Published: 2016
• Subjects: Philomachus pugnax
• Online Access: http://imis.nioz.nl/imis.php?module=ref&refid=255409

Intensive dairy farming has changed the agricultural grassland areas of TheNetherlands profoundly, with negative impacts on the reproduction of the shorebirdsbreeding there. This modern agricultural landscape also forms a stagingsite for migrating shorebirds, where they moult and replenish fuel stores, butstaging performance in these areas has received much less attention. Westudied northbound migrating Ruffs Philomachus pugnax staging in the grasslandsof southwest Friesland over a ten year period, during which peak numbersdeclined from 20,000 in 2003 to 3500 birds in 2009 and then stabilized. On thebasis of resighting locations of individually marked birds, we describe changes intheir day-time foraging distribution from spring 2006 to spring 2013. Ruffsprogressively retreated to the centre of the c. 10,000 ha study area, where,among intensive grasslands, established and newly created inland wetlandsoccurred that served as feeding and/or roosting sites. To quantify the spatialchanges, in 2013 we repeated a transect survey of meadow use carried outearlier in 2003. Using similar characteristics of individual meadows in terms ofherb richness (a measure of agricultural intensity) and landscape characteristics(distance to the roost, soil type), we show that, during spring 2013, as in 2003,Ruffs foraged preferentially on meadows close to roosting areas. The surveyalso highlights the preference of Ruffs for the Workumerwaard, a particularlylarge and open polder with a sandy soil and short vegetation bordered by a traditionalroosting area on the shoreline. This study provides some evidence thatinland wetlands may increase the attractiveness for migrating Ruffs of landscapesdominated by modern grasslands