Comparative diurnal and nocturnal diet and foraging in Eurasian Golden Plovers and Northern Lapwings wintering on arable farmland

Auteur(s): Gillings, S; Sutherland, WJ
Bron: ARDEA, 95 (2): 243-257; FAL 2007
Abstract: Knowledge of diet and intake rates are useful first steps in
understanding the distribution and behaviour of foragers. The diet of
Golden Plovers and Lapwings feeding on arable farmland has been rarely
studied, yet these species increasingly occupy this habitat in winter.
They are known to feed at night but little is known about their diet
and foraging success at night. This study aimed to describe and compare
diurnal and nocturnal foraging behaviour in order to explain spatial
and temporal patterns in foraging. Over three winters
(1999/2000-2001/02) diurnal and nocturnal observations of focal
individuals and collection of faecal samples were used to reconstruct
diet and quantify intake rates across a range of arable habitats.
Numerically, arthropods (mostly Carabids and millipedes) were the main
diurnal prey types but by biomass, small earthworms were the major prey
items. Diurnal intake rates were low but comparable with other studies of these species, prompting questions concerning the profitability of
feeding on agricultural farmland and the pause-travel foraging mode.
Nocturnal intake rates were up to 50% higher due to a greater reliance
on catching large earthworms at night. Diurnal intake rates were
highest during mild weather and on grass and sugar beet stubble fields;
they were lowest on cereal crops, yet this was the habitat most
consistently occupied. Current methods for assessing earthworm
abundance limit further explanation of foraging behaviour.