• English, Philina A.
  • Mills, Alexander M.
  • Cadman, Michael D.
  • Heagy, Audrey E.
  • Rand, Greg J.
  • Green, David J.
  • Nocera, Joseph J.
  • Simon Fraser University
  • York University


We tracked 20 males and 2 females breeding in four regions of Canada using geolocators. Wintering locations ranged from the gulf coast of central Mexico to Costa Rica. Individuals from the northern-most breeding site and females tended to winter furthest south, although east-west connectivity was low. Four individuals appeared to cross the Gulf of Mexico either in spring or autumn. On southward migration, most individuals interrupted migration for periods of up to 15 days north of the Gulf, regardless of their subsequent route. Fewer individuals showed signs of a stopover in spring.


We deployed light-logging geolocation tags (Fig. 1), hereafter “geolocators”, in four regions spanning a 1000 km stretch of the species’ range in Ontario, Canada: Rainy River District, Norfolk County, Muskoka District Municipality, and Frontenac County (Fig. 2). The Rainy River site (48° 49–59’N 94° 0–21’W) consisted of a 40000-hectare mosaic of agriculture, poplar (Populus sp.), coniferous forests, logged areas, and wetlands. The Norfolk County site (42° 42’N 80° 21–28’W) was St. Williams Conservation Reserve, which consists of two forest patches totaling 1035 hectares of pine-oak sand barrens and pine reforestation in a zone of intensive agriculture. The Muskoka district sites (including portions of neighbouring Parry Sound District and Simcoe County; 44° 22–56’N 79° 08–47’W) contained extensive pine-oak rock barrens. The Frontenac County site (44° 28–34’N 76° 20–25’W) was Queen’s University Biological Station, which consists of over 3200 hectares of deciduous forest and abandoned farmland in various stages of succession, both with scattered small rock barrens.