Der Rohrschwirl (Locustella luscinioides Savi)

Savi’s Warbler Locustella luscinioides has established as a nesting species in a few shallow reed lakes of southern Sweden during the last twenty years. Knowledge of the habitat requirements of a newly established species is important to maintain a viable population and design action plans. We examined the vegetation parameters in occupied territories of Savi’s Warblers at Lake Tåkern, the country’s stronghold for the species. We found association with the outer edge zones and fragmented areas of vegetation dominated by common reed Phragmites australis. Occupied territories differed from randomly chosen unoccupied (control) sites by having a thicker layer of basal litter, and on average more willow bushes (Salix spp.). Reed density and height did not differ between occupied territories and control sites. It is likely that the Tåkern population will continue to increase until it is limited by lack of willows or dense basal litter, the traits important for the establishment of territories. It is also likely that the species will continue to increase in Sweden as long as suitable reed habitats are left unaffected.

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Low frequency of extra-pair paternity in Savi's Warblers (Locustella luscinioides)

Behaviour ◽

10.1163/000579510x517217 ◽

2010 ◽

Vol 147 (11) ◽

pp. 1413-1429 ◽

Cited By ~ 5

Author(s):

Dennis Hasselquist ◽

Bengt Hansson ◽

Júlio Neto

Keyword(s):

Life History ◽

Bird Species ◽

Low Frequency ◽

Passerine Bird ◽

Migratory Bird ◽

Life History Strategies ◽

Similar Species ◽

Extra Pair Paternity ◽

Historical Factors ◽

Locustella Luscinioides

AbstractAlthough the frequency of extra-pair paternity (EPP) has been described for many species, the relative importance of the various contemporary and historical factors explaining EPP variation is still the subject of debate. In this study, we found 11 polymorphic microsatellite loci in the Savi's Warbler (Locustella luscinioides), and used eight loci to analyze the paternity of 392 nestlings belonging to 102 broods of this little-known species. The frequency of EPP was 4.1% of nestlings and 5.9% of broods, which is surprisingly low given what is known about Savi's Warbler's life history and ecology, and among the lowest found of any socially-monogamous passerine bird. Comparisons with similar species indicate that this low frequency is unlikely to have been determined by the ancient evolution of life history strategies. Our observations suggest that the costs of engaging in extra-pair copulations might be high for the females. Larger males, particularly those with longer bill and tarsus, are more likely to be cuckolded; and the few possible comparisons between cuckolded males and extrapair sires reveal a similar pattern. We further show that bill and tarsus lengths correlate with arrival date, which is associated with individual quality in many migratory bird species.

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