Wilde Zwaan Cygnus cygnus voor het derde jaar broedend in ZW-Drenthe
Drentse vogels , Volume 21 - Issue 1 p. 16- 19
. After failing to raise young in 2005, a pair of Whooper Swan near Wapserveen in SW-Drenthe produced two young in 2006 and four in 2007. In 2005-07 breeding took place on the same nest. In the last week of March 2007 five eggs were laid, hatching on 28 April After some days the family left the nest site and moved to the nearby marshy grassland polder, where they mainly fed on Water Horsetail and various grasses. On 30 May one young had disappeared and on 30 June four cygnets were ringed (aluminium, and yellow darvic rings). Soon after, the family switched to a sand pit at a distance of 5 km (as the)' did in 2006). Approximately on 20 August at the age of ca. 120 days, the cygnets were able to fly. At the same time the female started moulting her primaries, followed by the male in early September. After completing moult the family stayed on pastures in the valley of the Wapserveense 6c Stecnwijker Aa till the end of 2007. The two young of 2006 stayed with there parents till mid-March 2007 and were seen in the area till 30 April. Between 30 April and 19 September they were not observed in the area, but during 19 june-24 August two Whooper Swans, most likely these young, were observed near Beilen in central Drenthe (20 km NE of the breeding site). On 19 September (after moulting) they returned to the breeding area but stayed separated from the family with their four cygnets (further details see van Dijk 2006a, b).
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