Improving population estimates of Swedish birds using the Breeding Bird Survey fixed routes and correction factors from Finnish line transect surveys

I estimated population size of fifty-nine common birds by using the fixed routes of the Swedish Bird Survey (SBS), which give the number of birds per kilometer. I converted this number to density, birds/km2, using the correction factors for detectability that have been developed for line transects in Finland. I compared the population estimates by this new method with those in a previous account from 2012, in which the estimates of common birds were primarily based on extrapolation of habitat-specific densities from numerous territory mapping plots. There was good agreement for the most abundant species but a clear tendency that the estimates with the new method were higher for many less common ones. As little new density data are being collected, the SBS fixed routes are likely to be the prime source of data for future national population estimates. Although the Finnish correction factors can be used to improve the Swedish estimates for suitable species it is advisable to develop factors specifically adapted to the Swedish counts for application to a wider spectrum of species

Onset of breeding among Swedish Starlings Sturnus vulgaris in relation to spring temperature in 1981-2003

Both spring temperature and date of the first Starling Sturnus vulgaris egg were highly correlated between different study sites and weather stations in the southern half of Sweden. In southern Sweden, but not in northern Sweden, onset of breeding correlated strongly with spring temperature, particularly during the last ten days of April, the period that happens to coincide with the start of breeding. The response was one to two days per degree. No response was found with periods relative to the start of egg-laying, indicating that in the latter part of April the general conditions for breeding are normally satisfied as soon as temperature reaches a certain level. Possible climatic trends were too weak to be detected in the noise of the annual fluctuations. The best current estimate of long-term spring temperature increase during the next one hundred years is four degrees, which would mean that the Starling will start egg-laying 4-8 days earlier at the end of the present than at the end of the previous century

The recent decline of the Starling Sturnus vulgaris population in Sweden: a 22-year nest-box study / Den sentida nedgången av starens Sturnus vulgaris bestånd i Sverige: en 22-årig holkstudie

This study reports the changes in number of breeding Starlings Sturnus vulgaris as recorded in seventeen areas distributed over all Sweden in 1981-2002. The number of breeding attempts declined by about fifty percent, consistent with the general decline observed in the Swedish Breeding Bird Survey. In no area was a long-term increase observed. There was no consistent geographical pattern; areas with declines and areas with stable populations occurred in all parts of Sweden. Reduction of farming and grazing intensity was probably the most important factor since the populations did not decline in areas with continued active farming. The declines were confined to small infield sites surrounded by large forests. Hence the general decline is probably driven by rapid habitat deterioration at numerous small sites rather than by a slow, similar decline in all habitats

Sewage sedimentation ponds - a lost bird paradise : a nostalgic return visit and case study

Sewage ponds with exposed sludge are known to be excellent feeding sites for waders during migration. They still exist in parts of the world but are disappearing in pace with introduction of modern methods which do not involve open exposure of the sludge. Here I report a five-year study from a Swedish plant with open sludge ponds in the 1950s when many similar ones were still active. I counted the waders with frequent visits from 18 April through 2 November, 1952–1956. Ninety-three percent of the dates had a visit in at least one of the years giving an almost complete combined coverage of migration. Nineteen species were recorded at least once. The total average annual number of bird-days was 2868 (5% in spring). Most abundant were the Ruff Calidris pugnax with 35% and Wood Sandpiper Tringa glareola with 32% of all bird days. Temminck’s Stint Calidris temminckii showed the highest spring proportion of bird-days, 30%

Bevakning av häckningsframgången hos staren. Årsrapport för 2008.

(1) Populationsutvecklingen har länge varit stabil och populationen god i bevakningsområdena Revinge, Berg, Fleringe och Kvismaren. Tendensen har tidigare varit negativ i Tiveden, Grimsö och Ottenby. Beståndet har länge varit litet i Tyresta. Under senare år har det dock skett viss återhämtning i områdena med tidigare nedgång. Efter åtgärder (nya holkgrupper) är situationen både för bevakning av häckningsframgången och provtagningen för miljögiftanalyseer tillfredsställande i alla områden utom Tyresta, där en ny holkgrupp skall etableras. (2) Äggkullstorleken, antal flygga ungar och andelen flygga ungar av antal lagda ägg var höga 2008 och har varit tämligen stabila det senaste kvartsseklet. Antalet flygga ungar per häckning var ett av de bästa någonsin

Development of the Goshawk Accipiter gentiles population in Sweden since 1975. / Duvhökens Accipiter gentilis beståndsutveckling i Sverige sedan 1975.

I have used data, mainly from south of 62degreeN, collected within the Breeding Bird Survey and the Winter Bird Count (1975-2001) to describe the population development of the Goshawk Accipiter gentilis in Sweden. The data from the breeding season indicate a considerable population increase. The winter data show a stable population for the winters 1975/1976-1993/94, then six winters with lower values, and a return to the former mean level in 2000/2001. The linear trend for the whole period shows a decline of almost 20%. The winter data are difficult to interpret in terms of breeding population since a large proportion of the hawks are wintering birds from northern Sweden and Finland. The conclusion is that the number of overwintering Goshawks in southern Sweden has declined, especially in recent years, but that the breeding population has increased, or - considering the weak summer data - at least not declined during the last quarter of a century