Excavator: Ground. The nests are aggregated with a minimum distance between the nest entrances of about 10cm. The nesting density may lie between 10-20 nests per square metre. Nests were found on SSW directed slopes and adjacent flat ground. The surface of the ground was bare with small stones and lichen crusts. The nests are constructed in fine sandy soil of morainic origin. At the Abisko nesting sites in Arctic Sweden, the sun is above the horizon permanently between 31 May and 14 July.