Abstract
The distributions and abundances of Grey Wagtails Motacilla cinerea and White Wagtails M. alba were surveyed using a line transect census in central and south-eastern Hokkaido from late April to early July between 1976 and 2014. The transect was 2 km in length and 50 m in width. One thousand and nine transects were situated in 900 4.5 km-by-5 km quadrats. Grey Wagtails occurred in 321 transects (32%) and 300 quadrats (33%) mainly in mountainous areas, while White Wagtails were detected in 468 transects (46%) and 440 quadrats (49%) mainly in plains. The occurrence frequencies of Grey Wagtails were 9% in Siberian dwarf pine forests, 27% in ever-green coniferous forests (Aa), 58% in mixed forests (Ac), 53% in deciduous broad-leaved forests (Ad), 28% in larch plantations (Ag), 30% in agricultural land with woods (Cw), 10% in agricultural land (C) and 9% in residential areas (D). Those of White Wagtails were 0%, 13%, 4%, 7%, 4%, 63%, 87% and 89%, respectively. The occurrence frequencies of Grey Wagtails at less than 200 m above sea level (asl), 201-400 m asl, 601-800 m asl, 601-800 m asl and 801 m asl or above were 25%, 45%, 52%, 46% and 31%, respectively. Those of White Wagtails were 60%, 30%, 11%, 4% and 6%, respectively. The average numbers of Grey Wagtails per 2 km were 0.2 ± 0.6 in Aa, 0.7 ± 0.9 in Ac, 0.6 ± 0.9 in Ad, 0.2 ± 0.7 in Ag, 0.4 ± 0.8 in Cw, 0.1 ± 0.4 in C, 0.2 ± 0.6 in D. Those of White Wagtails were 0.1 ± 0.3, 0.1 ± 0.3, 0.1 ± 0.4, 0.04 ± 0.2, 0.8 ± 1.0, 1.5 ± 1.2 and 1.8 ± 1.2, respectively.
