Nielsen, H.H. & Clausen, P. 2021. Ynglende og rastende fugle i Vejlerne 2019. Aarhus Universitet, DCE – Nationalt Center for Miljø og Energi, 57 s. - Teknisk rapport nr. 195. http://dce2.au.dk/pub/TR195.pdf
Since 2007, the Aage V. Jensen Nature Foundation and the Department of Bioscience, Aarhus University have had an agreement to undertake extended annual monitoring of selected breeding and migratory birds at the Foundation’s Vejlerne reserve. This report provides a detailed review of the breeding birds as well as summary results of the monitoring of staging migratory species for 2019.
As well as monitoring the status and abundance of a variety of species at the site, avian monitoring at Vejlerne contributes to the national monitoring programme NOVANA. This delivers consistent, quality-assured nationwide data as the foundation for the Environmental Protection Agency's preparation of plans for protected Natura 2000 sites, as well as providing data for the official Danish reporting to the EU. Full details of the monitoring methods are described in more detail in the technical instructions, which are referenced in the report. More extensive bird monitoring is carried out at the Vejlerne reserve than is strictly necessary under NOVANA (whose primary focus is Annex 1 species), including additional breeding species, carried out annually (whereas currently NOVANA typically monitors species every other year). Similarly, staging migrant species are monitored year-round, in contrast to under NOVANA, where species are monitored only during the months when the national population typically reach their maximum abundance.
Among the breeding birds in 2019, record breeding numbers were reported for common crane in Vejlerne and great white egret in a plantation immediately west of the Eastern Vejler. For several ground-nesting meadow species (whose occurrence typically peaked during 2000-2003), numbers in 2019 were at or below the levels observed in the previous ten years (2009-2018), although their levels of abundance remained below those of earlier years (2000-2003). This was especially true for the marsh species such as lapwing, black-tailed godwit, redshank, ruff, dunlin and arctic tern, where the latter three have shown consistent declines since the 1980s and 1990s. After an exceptionally good breeding year in 2018 (178 pairs), avocet had another poor breeding season with just 53 pairs in 2019. Numbers of breeding black tern have also been steadily declining since the late 1970s and the 20 pairs that attempted to breed in 2019 failed to raise offspring. For several of the breeding species, the low numbers in recent years may be the result of dry springs and summers, in combination with high local predation pressure. Table 4 of the report highlight the significance of Vejlerne for breeding birds in an international and national perspective. Two species, Eurasian bittern and dunlin from the Baltic population breed in numbers that exceed international 1% population criteria and many other species have far more than 1% of the national population.
Notable occurrences in amongst migrants in 2019 were record numbers of great white egret, common teal, shoveler, common crane and golden plover compared to numbers during 2008-2018 (cf. Nielsen & Clausen 2019a,b). Bewick’s swans were largely absent, while Eurasian spoonbill, common coot and wood sandpiper were counted in relatively low numbers compared to before. By early March, there were over 50,000 geese in the area, especially pink-footed and barnacle geese. A large number of species occurred in 2019 in numbers that exceeded international or national 1% of flyway population criteria as described in the report.