Abstract

Red-throated Loons Gavia stellata have disappeared from breeding sites regularly used in the mid-1990s, but it is not clear if this reflects a population decline or movements to other sites. Therefore, we searched for potential breeding sites, including sites with old records, in three regions in southern Sweden, where it was possible to repeat surveys conducted in the past. A pattern of abandonment and return to breeding sites was verified; around 30% of the sites were abandoned over a 10-year period, but the loss was largely compensated by establishment at new sites or return to sites used in the past. But almost one quarter of the sites were used in about 75% of the breeding seasons across a period of more than 30 years. Annual breeding success at these sites did not differ from that at the other, less frequently used sites. However, the most continuously used sites produce a larger total of young than other sites and are therefore important for long-term recruitment. They should be identified and prioritised for protection and management.

Highlights

  • Red-throated Loons Gavia stellata have disappeared from breeding sites regularly used in the mid-1990s, but it is not clear if this reflects a population decline or movements to other sites

  • Hotbilden är komplex och innefattar bland annat direkt eller indirekt påverkan av markavvattning vid häckningstjärnarna och utglesade bestånd av bytesfisk i fiskevattnen

  • Karvik noterade smålommar vid bara fem (17%) av de 29 lokalerna med häckning under ett eller flera år under perioden 1994–2012

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Summary

Introduction

Red-throated Loons Gavia stellata have disappeared from breeding sites regularly used in the mid-1990s, but it is not clear if this reflects a population decline or movements to other sites. Smålommen Gavia stellata har länge uppmärksammats i det svenska fågelskyddsarbetet mot bakgrund av farhågor för en långsiktigt minskande trend och en låg ungproduktion Inom ramen för inventeringarna har flera rapportörer noterat att många smålomstjärnar som var regelbundet bebodda av häckande fåglar under mitten och slutet av 1990-talet har stått tomma under senare år, men det har varit oklart om detta beror på en minskning av populationens storlek eller på en omflyttning till andra häckningstjärnar. Inventeringarna inom Projekt LOM visar att smålommens häckningsframgång kan ha varit för låg för att kompensera för den årliga dödligheten på Sydsvenska Höglandet och i artens svenska kärnområde i Svealand, medan häckningsutfallet har varit bättre i Norrland (Eriksson 2012)

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