Ardea
Official journal of the Netherlands Ornithologists' Union

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Piper S.E. (2001) Elucidating population structure in the Long-tailed Wagtail Motacilla clara: The use of the space-time diagram. ARDEA 89 (1): 113-122
The Long-tailed Wagtail Motacilla clara is the African analogue of the Palearctic Grey Wagtail Motacilla cinerea. It may be expected that their demographies and life-history strategies should be similar, but this is not so. The African species has a higher survival rate (65.5 2.5% yr-1 versus 46.3 7.9% yr-1 for Grey Wagtail), seldom shows partial migration and generally holds permanent and life-long territories. The concept of a space-time diagram was used to track individuals holding linear territories along a river. Using data from a 22-year study of the autecology of the Long-tailed Wagtail it was shown that the population was comprised of six components. Breeding pairs that occupied permanent territories, often held for life. The boundaries of most of these territories did not change from 1977 to 1999. Breeding pairs that occupied temporary territories inserted between existing breeding territories along the river and held by a pair for periods of three months to seven years (Only once did a pair breed therein). Temporary pairs attracted to gaps between permanent territories that stayed a few months. Solitary floaters that occupied interstitial territories for a few months. Floaters having located a 'preferred' area reappeared there from time to time until they either gained a territory or disappeared. Floaters who passed through many territories until dying or locating a preferred area


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