Nalegsel van Drentse Raven Corvus Corax succesvol
Drentse vogels , Volume 21 - Issue 1 p. 78- 80
After almost a century of absence Ravens started to breed again in the northern Netherlands in 2003. A single pair raised 2 and 3 young in 2003 and 2004 respectively, but was not successful in 2005. In August 2005, an adult male, presumably belonging to this pair, was found freshly dead. Since early 2006, however, a pair again roamed western Drenthe, but apparently did not attempt to breed. In 2007, a newly built nest in a Scots pine Pinus sylvestris was found in early March, but this breeding attempt failed shortly afterwards. A repeat laying was produced in a newly built nest in a Scots pine some 180 m away from the failed nest. This nest produced 4 chicks (2 males weighing 1240 g on 31 May, 2 females 1040 and 1060 g respectively; wing lengths respectively 295 and 288 mm for the males, 285 and 277 mm for the females). Lateral tarsus width did not show sex-specific variation, ranging between 10.0 and 10.3 mm (no pressure on calliper). Egg laying in this repeat clutch must have started on 30 March. After fledging in early June never more than three young were recorded, the last observations made on 12 and 15 September (ringed juvenile).
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