The breeding biology of the Lapland Bunting Calcarius lapponicus in West Greenland during two contrasting years

The breeding biology of the Lapland Bunting was studied in an area of central West Greenland during two contrasting seasons. In the delayed thaw of 1984, male birds arrived on the breeding grounds at the same time as in the more typical spring of 1979, but females delayed arrival by two weeks in 1984 compared with 1979. Mean clutch size was depressed in the latter year and declined through the season; breeding productivity was correspondingly reduced in 1984 compared to 1979. Egg and juvenile predation rates were similar for the two years. Nestlings grew as rapidly in 1984 as in 1979 despite an apparent reduction in detected ground‐dwelling invertebrates known to form an important constituent of the nestling diet. Because they bred later in 1984, females tended to commence moult later in 1984 than 1979 but completed moult by early September in both years. Males also commenced moult later but completed earlier in 1984.