Seasonal variation in home-range size and habitat area requirement of lesser spotted woodpeckers (Dendrocopos minor) were studied by radio-tracking in southern Sweden for 6 years. Home-range size did not vary between age-groups or sexes, but varied with season and decreased successively from 742 ha in winter (n = 10), 355 ha in early spring (n = 15), 103 ha in late spring (n = 22) to 43 ha during nesting (n = 10). The home-range in late spring (i.e. the 3-5 weeks preceeding egg-laying) represents the defended breeding territory. This included on average 39 ha of forest utilised for foraging (range 31-46 ha, n = 15). Since food availability in late spring has a significant influence on reproductive success, and mortality is highest in this period, we regard this as an estimate of the habitat area requirement. This estimate is valid primarily for birds in southern Sweden, but circumstantial evidence indicate that the area requirement may not be grossly different in other areas with different forest types. For conservation of lesser spotted woodpeckers, management should focus on a minimum of 40 ha of forest dominated by deciduous trees, which may be fragmented over a maximum of 200 ha, (C) 2001 Elsevier Science Ltd. All rights reserved.