Aarhus University Seal / Aarhus Universitets segl

No. 154: Breeding and resting birds in Vejlerne 2018

Nielsen, H.H. & Clausen, P. 2019. Ynglende og rastende fugle i Vejlerne 2018. Aarhus Universitet, DCE – Nationalt Center for Miljø og Energi, 48 s. - Teknisk rapport nr. 154.  http://dce2.au.dk/pub/TR154.pdf

Summary

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. During 2018, the consultancy firm Avifauna Consult undertook the monitoring programme, the results of which are presented in this report.

As well as monitoring the status and abundance of a variety of species at the site, with the aim to inform the Vejlerne Reserve Management Board of Aage V. Jensen Nature Foundation, the avian monitoring at Vejlerne contributes to the National Monitoring and Assessment Programme for the Aquatic and Terrestrial Environment. (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 (e.g., for dabbling ducks September/October, diving ducks in midwinter and several species of waders in April/May or August).

Among the breeding birds in 2018, record breeding numbers were reported of spoonbill 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 2018 were at or below the levels observed in the previous nine years (2009-2017), although their levels of abundance remained below those of earlier years (2000-2003). This was especially true for the saltmarsh species such as lapwing, black-tailed godwit and redshank, but was also the case for ruff, dunlin and arctic tern that have shown consistent declines since the 1980s and 1990s. Avocet, on the other hand, bred in surprising abundance in 2018 and with the highest number since 2008. Numbers of breeding black tern have also been steadily declining since the late 1970s and the 24 pairs that attempted to breed in 2018 failed to raise any 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.

Notable occurrences in amongst migrants in 2018 were record numbers of great white egret, grey heron, spoonbill, common crane and shoveler, compared to numbers during 2008-2017 (cf. Nielsen & Clausen 2019), whose numbers except for Shoveler were dominated by local or regional breeding populations with offspring. Swans and Common Coot were counted in relatively low numbers compared to previous years, while most geese, ducks and diving ducks appeared in similar numbers to recent years. A large number of species occurred in 2018 in numbers that exceeded international or national 1% of flyway population criteria as described in the report.