Red Knots with Different Winter Destinations: Differential use of an Autumn Stopover Area

• DOI: 10.1675/063.033.0312
• Publication Date: 2010-09-28T16:29:00Z
• Authors: Brian A. Harrington; Stephanie Koch; Larry K. Niles; Kevin Kalasz
• Keywords: 01 natural sciences; 0105 earth and related environmental sciences

Abstract. Southward migrating Red Knots (Calidris canutus) were surveyed on Cape Cod, Massachusetts. Unique markers, including ones applied to birds in wintering areas in North and South America, were found. Northern and southern-marked knots had different migration chronologies, plumage characteristics and flight feather molt. Knots from the two groups were found to have different foods and foraging habitats. Numbers of knots more than one year old were found to increase from mid-July to mid-August, decline during late August and then increase in September–October. As numbers declined in August, the proportion of knots from South America decreased and, by 1 September, all remaining marked birds had been tagged in North America. Average minimum stopover durations were found to vary according to original banding locations, e.g. 8.5 (±2.6) days for South America, 14.2 (±3.2) days for Delaware Bay, 16.1 (±3.5) days for the U.S. mid-Atlantic coast and 49.5 (±24.6) days for Florida. The proportion of knots wit...