Solothurn, Switzerland
Solothurn, Switzerland

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Christen W.,Langendorfstrasse 42
Ornithologische Beobachter | Year: 2017

In the 32-km2 plain of the Aare between Büren a.A. (canton of Berne) and Solothurn (canton of Solothurn), population sizes of the following 10 bird species were monitored during the breeding seasons 1982-2016: Common Quail, Grey Heron, Common Cuckoo, Common Nightingale, European Stonechat, Common Whitethroat, Eurasian Golden Oriole, Red-backed Shrike, Rook, and Corn Bunting. Population trends in the 35 years of the study differed among species. Population sizes clearly increased in Common Nightingale, European Stonechat, Red-backed Shrike, and Rook. Numbers of Grey Heron increased in the beginning of the study, reached a maximum in the middle of the nineties, and decreased slightly since then. Clear decreases were found in Common Whitethroat and Corn Bunting, and a slightly negative trend was found in the Eurasian Golden Oriole. No clear trend was observed in Common Quail and Common Cuckoo. The population trends in the plain of the Aare were compared with the Swiss Bird Index SBI®, which has been used since 1990 to calculate population indices for all breeding bird species in Switzerland. Numerous potential reasons for the fluctuations in the populations are to be found in the breeding grounds as well as in stopover sites and wintering areas. In the breeding ground, promoting wildflower fallows could support the populations of European Stonechat, Common Whitethroat, Red-backed Shrike, and Corn Bunting.

Martinez N.,Basellandschaftlicher Naturund Vogelschutzverband BNV | Martinez N.,Hintermann and Weber AG | Luthi T.,Vogelschutzverband des Kantons Solothurn VVS | Muller W.,Schweizer Vogelschutz SVS BirdLife Schweiz | And 7 more authors.
Ornithologische Beobachter | Year: 2013

The Middle Spotted Woodpecker Dendrocopos medius is one of 50 priority species for species recovery programmes in Switzerland and its Red List status is considered as Near Threatened. Nevertheless, knowledge of the exact distribution and accurate population size in several cantons containing strongholds of the species are inadequate or outdated. The poor quality of the data is mainly due to the cryptic life of the Middle Spotted Woodpecker. Thus, it can only be recorded reliably with species-specific survey methods. Population surveys with such methods were previously missing from the cantons of Basel-Landschaft, Basel-Stadt and Solothurn, although these cantons are known to be important distribution centres for the species. For these reasons, a species-specific survey was conducted in 2012 to assess population size and distribution of the Middle Spotted Woodpecker in potential habitats in these cantons. Simultaneously, the same method was applied in adjacent regions of the canton of Bern. Overall, we found 415 territories, and we estimated total population size for the four cantons at 455 to 610 breeding pairs. This corresponds to a fivefold increase compared to older data. The comparison with existing data shows that this difference is partly due to methodological differences between the surveys. However, part of the observed increase is also due to a real population increase and an associated range expansion. Due to the large and increasing population, the Middle Spotted Woodpecker is barely threatened in northwestern Switzerland for the moment. However, since oaks of medium ages classes are rare in many forests because oak regeneration was neglected in the 20th century, specific measures for the Middle Spotted Woodpecker should remain an important component of forest management.

Aye R.,Schweizer Vogelschutz SVS BirdLife Schweiz | Bernardi E.,University of Lausanne | Christen W.,Langendorfstrasse 42 | Horch P.,Schweizerische Vogelwarte | And 12 more authors.
Ornithologische Beobachter | Year: 2013

The Corn Bunting is classified as Vulnerable according to the Swiss Red List and a priority species for recovery programmes. Its population in Switzerland has been estimated at 400 to 600 pairs in the years 1993-1996. The objective of the present study was to establish an updated population estimate for the period 2009-2011 and to identify the core areas for the conservation of the species. We based our population estimate on monitoring projects existing in four areas with corn bunting populations and for the rest of Switzerland on casual observations collected by the Swiss Ornithological Institute. This procedure resulted in an estimate of 93 to 103 territories on average for the years 2009-2011. The species has disappeared from many areas and a decline of about 80 % since the mid-1990s has to be assumed. Species recovery should therefore be of high priority in the remaining populations and in areas with a high potential. The current core areas of the species are the Champagne genevoise, the Grosses Moos, the Klettgau and the region from Lake Neuchâtel to Lake Geneva.

In June 2015, a pair of Western Bonelli’s Warblers nested in a garden at the edge of the village of Romont (canton of Berne, 700–750 m a.s.l.). The nest was situated in a embankment, at a distance of only 3 m from the street and 7.5 m from the house. © 2016, ALA. All rights reserved.

Wintering numbers of Eurasian Wigeon along the river Aare between the «Häftli» near Büren a.A. (canton of Berne) and the town of Solothurn (canton of Solothurn) strongly increased in the last decades. Most Wigeon are usually observed along the 7 km long stretch of the «Häftli», an oxbow lake of the Aare. Here, numbers started to increase in the first half of the 1990s. Between 2000/01 and 2013/14 the mean daily maximum per winter was 370 individuals. In five winters more than 400 individuals were observed on a single day, with a maximum of 550 on 12 January 2013. When the oxbow lake is completely ice-covered the Wigeon move to the stretch of the river downstream of Büren. As long as there is little human disturbance they graze on the adjacent fields. Overall wintering numbers in Switzerland from 2000 to 2013 according to the Swiss waterbird census amounted to a mean of 1397 individuals in January, not including the foreign parts of the transboundary lakes. In the study area a mean of 312 Wigeon were counted during the waterbird census, amounting to 22.3 [%] of the national total. The area is the most important wintering area for Wigeon in Switzerland. © 2015, ALA, All rights Reserved.

In the literature, the autumnal migration call of young Common Chiffchaffs Phylloscopus c. collybita is described with a plaintive, disyllabic «sweeoo» or similar. In the surroundings of Solothurn in western Switzerland, birds with this call type were not present every autumn and winter. In autumn 2008, with mostly continuous winds from NE, such calls were heard very frequently. Whether this call type is uttered just by young birds or also by adults from eastern populations or dialect areas is not known. Remarkablyy about half of the breeding birds uttered the «sweeoo» call in the breeding season 2009 around Solothurn. Both in 2010 and 2011 this call was not heard any more from breeding birds.

Between 11 and 27 June 2014 a singing Greenish Warbler Phylloscopus trochiloides was observed repeatedly near Gänsbrunnen (canton of Solothurn) on the northern slope of Weissenstein in the Jura mountains. The bird was mostly singing on large sycamore and beech trees near forest tracks with steep embankments, at an altitude of 1080 to 1220 m a.s.l. The habitat consists of a large north-facing forest with an inclination of 55 %. The song posts were spread over a distance of 800 m. The wide-ranging movements of the bird indicate that it was probably not paired. This is the fourth record of a Greenish Warbler in Switzerland. © 2015, ALA. All rights reserved.

In the plain of the Aare between Büren a.A. (canton of Berne) and Solothurn (canton of Solothurn) all observations of Tree Pipit Anthus trivialis, Meadow Pipit A. pratensis, Water Pipit A. spinoletta, Western Yellow Wagtail Motacilla flava, Whinchat Saxicola rubetra and Northern Wheatear Oenanthe oenanthe were systematically recorded from 1981 to 2012. These six species occur here regularly during autumn and spring migration and yearly in varying numbers. Larger gatherings occur especially when held up by bad weather. The seasonal occurrence is described and shown in phenological diagrams. The migration pattern is compared with other areas in Switzerland. So far the seasonal occurrence of rather common species in Switzerland was roughly described (Glutz von Blotzheim 1962, Winkler 1999) and shown in schematic graphics (Maumary et al. 2007). Phenological diagrams of autumn and spring migration from the same areas on the basis of five-day periods (Berthold 1973) are only available so far for few species and regions, including the area of Lake Constance (Schuster et al. 1983, Heine et al. 1999). On the two Alpine passes Col de Bretolet (canton Valais) and Col de Jaman (canton Vaud) the medians of autumn migration for Tree Pipit (13-14 days), Western Yellow Wagtail (4-7 days), Whinchat (15-17 days) and Northern Wheatear (7-11 days) are markedly earlier than in Solothurn. This could suggest that the four long-distance migrants avoid crossing the Alps with progressing migration and prefer to migrate along the Swiss plateau. With more information on widespread species from daily lists recorded via the online platform it will be possible to increase the number of species for which phenological diagrams can be compiled.

The Aare plain between Büren a.A. (canton of Berne) and Solothurn (canton of Solothurn) covers an area of 32 km2 of mainly agricultural land. After snow melt and intensive rainfall patches of land are flooded and attract numerous waders migrating across Switzerland. From 1981 to 2009 an overall number of 23827 individuals from 36 species (excluding Northern Lapwing) were recorded. The occurrence of waders varied greatly between years and across the seasons, depending on the availability of suitable habitats. On average, 17 (11-24) species were recorded per year. The sum of the maximum number of birds per five-day period amounted to 550 (155-2041). During periods of rainfall for several days migratory birds are held up, which results in high numbers of birds interrupting their migration. With 49 % of all observed individuals Common Snipe was by far the most abundant species, followed by Ruff (9 %), Common Sandpiper (8 %), Wood and Green Sandpiper (6 % each). The sums of the maximum numbers per five-day period indicated comparable intensities of spring (first half of the year) and autumn (second half of the year) migration in the long term. The largest numbers of waders were recorded on flooded patches in agricultural land (60 %), followed by the bank and the islands of the river Aare (14 %), agricultural land and other sites (11 %), «air», i.e. birds recorded in flight (7 %), ditches and ponds (6 %), and algal mats on the river (2 %). In the second half of the 1980s the Aare plain was evaluated as the third most important stop-over site for waders in Switzerland. It is doubtful whether this is still the case. Drainage projects in 1989 led to a marked reduction in temporarily flooded areas. When birds are disturbed, alternative refuge sites are lacking and birds leave the area. Out of the 14 most abundant species 9 showed a decrease of over 40 % between the periods 1981-1995 and 1996-2009, namely Black-tailed Godwit (-97 %), Common Redshank (-69 %), Ruff (-68 %), Spotted Redshank, Eurasian Curlew, Common Snipe, Dunlin, Little Stint and Common Ringed Plover.

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