Males arrive to the breeding ground in mid to late May and begin to sing in order to attract a mate.[1] In early June, females build their nests on the ground under dense grass or shrub cover, usually inside a low willow shrub, mountain birch,[2] or sunken in a depression of sphagnum moss.[3] Their nest is a well-covered shallow open cup of grasses or sedges.[8] Clutch size is typically 3-5 eggs[2] which are oval in shape and colored pale green to greenish-white and spotted reddish brown.[8] One egg is laid per day, and females begin incubating eggs before the clutch is complete, while males do not incubate.[10] Incubation lasts for about 12-14 days.[8] Young are born altricial and leave the nest about 9-12 days after hatching, although they may be cared for by their parents for another 2-3 weeks.[8] Fledglings are mostly flightless their first day, but their flying abilities quickly improve, and by day six they can fly more than 10 meters at a time.[2]