KLEEFSTRA R, VAN DIJK A-J, NIENHUIS J, SCHEKKERMAN H & VAN TURNHOUT C (2021) Breeding Eurasian Curlews Numenius arquata in the Netherlands: distribution, trends and breeding success of a wader in trouble. LIMOSA 94 (1): 4-18.
Throughout Europe numbers of breeding Eurasian Curlew
seriously declined over the last decades and the species is
classified as globally Near Threatened on the IUCN Red List of
Threatened Species. The Dutch breeding population shows a
similar negative trend and the Eurasian Curlew disappeared
as a breeding bird in a lot of habitats in the last decades.
This was reason for Vogelbescherming Nederland (BirdLife
the Netherlands) and Sovon Vogelonderzoek Nederland
(Dutch Centre for Field Ornithology) to declare 2019 the year
of the curlew, in which data from monitoring projects and
historical sources were analysed to detect which factors
influence the numbers and distribution of breeding Eurasian
Curlews and how they developed over time.
The long-term trend of breeding Eurasian Curlew in the
Netherlands was positive until the late 1970s, but declined
since (Fig. 1). Over the whole period (1975-2019) the decline
was 1.9% per year, but in the last 15 years the decline is 3.7%
per year. Compared to 1990, the national population has
halved. Based on Atlas data, the Dutch breeding population
in 2013-15 was estimated at 3800-4800 pairs. Negative trends
in nature reserves have been stronger than in agricultural
areas since 1984 (Fig. 2). The trends per region / habitat
show that Eurasian Curlews have virtually disappeared from
mainland dunes in the western part of the Netherlands, in
heathlands, peat moors and in peat bogs since 1984 (Fig.
3). The breeding numbers on the Wadden Sea islands are
declining as well.
The distribution of the breeding population over the various
habitats has changed radically in recent decades: from
breeding mainly in nature reserves in the 1950s to mainly
in agricultural areas nowadays (Fig. 5). In 2013-15, one third
of the agricultural curlew-population bred on arable land
and the remainder mainly on grassland. Breeding in arable
habitat is of a more recent date (since circa 1980). Within
nature reserves, grasslands with management for breeding
birds are particularly important.
The average start of egg-laying is April 14th (1985-2018), and
there is no significant advance or delay in this date (Fig. 9).
Nesting success in farmland shows large annual fluctuations
around an average value of 37.4%, with no clear trend in the
period 2000-20 (Fig. 10). In 2009-14, nesting success of these,
mostly protected, nests was above average, but decreased
from 2015. The average nesting success in nature reserves is
We discuss a wide range of possible explanations for changes
in trends and distribution, such as changes in natural habitats
(due to changes in management, grazing and nitrogen
deposition), low chick survival, and nest predation as main
drivers. Data indicate a low and strongly decreased breeding
success, both in heathland and agricultural land (Fig. 11 and
12). Insufficient reproduction is also considered to be the
main reason for the decline in other parts of Europe, mainly
due to intensification of agriculture in combination with
increased predation pressure. Many Dutch habitats are now
unsuitable and it is unlikely that sustainable populations
could be restored in dune areas, heathlands, moors and
bogs. Opportunities for improving breeding habitat lay in
agricultural areas and on the Wadden Sea Islands.
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