2021
Kraanvogel Grus grus als broedvogel in Drents-Friese Wold en Holtingerveld in ZW-Drenthe in 2013-21
Publication
Publication
Breeding of Common Crane Grus grus in SW-Drenthe in 2013-21. Drentse Vogels 35: 2-17.
In 2013 Common Cranes started breeding in SW-Drenthe (170 km2) as part of a westward expansion of the breeding range in Western Europe in the late 20th century. In 2021, the breeding population had increased to six pairs, with local densities of up to 0.6 pairs/km2 in a 5 km2 core area. Nesting took place on heathland with fens in the nature reserves of Doldersummerveld (256 ha), Wapserveld (210 ha) and Hoekenbrink (50 ha), with natural grassland, farmland and forest nearby. Occupied nests were 2.0-5.6 km apart. Most nests were found in vegetation of Soft Rush Juncus effusus with the local water depths ranging between 25 and 70 cm. Three nesting sites in areas of up to 0.6 ha in size were used in 7, 5 and 3 consecutive years. Out of a total of 30 territorial pairs in 2013-21, 21 laying attempts were initiated (17x first laying, 4 repeat layings after failure of first attempt) and six pairs raised a total of 9 chicks, resulting in 0.43 young/breeding attempt and 1.5 young/successful breeding attempt. In the breeding season territories were visited at least once per ten days, resulting in a rather wide margin of error where phenology is concerned. After settlement at the breeding site in February-March (mean date 28 February) nest building usually commenced after 3 weeks. In 2021, the birds arrived much later (late winter cold and wet) but started nest-building within 10 days. Start of egg-laying was recorded between 12 March and 16 April (mean 28 March, n=17, first layings only), on average 34 days (7-69, n=17) after arrival at the breeding site. Incubation lasted 30-36 days (mean 33, n=10). Eleven nests failed during the egg stage, on average 13 days into incubation (range 1-27 days. Four replacement clutches were started 2-5 weeks after loss of the first attempt; all repeats failed within 2-3 weeks. Initial brood size was 7x 2 and 3x 1 chick(s), but only three pairs raised two fledglings and another three pairs just one. Loss of chicks was observed 1-52 days (mean 3 weeks) after hatching. The period between hatching and fledging lasted 70-85 days (mean 78). Breeding pairs and families with chicks usually foraged in areas of 150-300 ha in size, consisting of a mixture of moorland or grassland with fens and adjoining woodlands. Families moved as far as 1800 m from the nest site. Annually 3-5, but sometimes up to 10, non-breeding Common Cranes were present in the study area in February-June, when conflicts with nesting pairs were common. Flight initiation distances recorded for incubating Cranes (6x) and families with dependent young (13x) ranged between 137 and 325 m (mean 227, SD=46.9).
Additional Metadata | |
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Drentse vogels | |
CC BY 3.0 NL ("Naamsvermelding") | |
Organisation | Werkgroep Avifauna Drenthe |
A.J. van Dijk. (2021). Kraanvogel Grus grus als broedvogel in Drents-Friese Wold en Holtingerveld in ZW-Drenthe in 2013-21. Drentse vogels. |