Bombycilla japonica · Japanese Waxwing
|datum||3 maart t/m 1 april 2005: 30 dagen|
|locatie||Riemsdijk, De Buurt en Arboretum De Leijen|
|coördinaten||N 51.97558 O 5.6477|
|aantal, kleed||1, adult man|
|status||Niet aanvaard, gepubliceerd in jaarverslag CDNA|
|opmerkingen||photographed, sound-recorded (identification accepted). This male present in a group of Bohemian Waxwings B garrulus in Wageningen from 3 March to 1 April 2005 was considered an escaped cage bird at the time (van der Vliet et al 2007). This was mainly based on the aberrant pale colouration of the waxy tips on the wing and tip of the tail feathers. Jansen (2019) showed that pale tail tips do occasionally occur in wild birds, and therefore cannot be regarded as a sign of captive origin. Based on these findings, the record was re-assessed. The colour of the waxy tips on the wing was not treated by Jansen (2019), and none of the birds with pale tail tips in his paper involved adult males. The committee considers the vagrancy potential of this species to be fairly low, also during an invasion of Bohemian (as was the case in 2005). For Bohemian and Cedar Waxwings B cedrorum, long distance migration has been proven, both from north to south and from east to west (and reverse). Japanese is a short- to medium-distance migrant at best, primarily in a north-south direction. In Cedar, it has been proven that aberrant tail colouration is diet related and not genetically determined. Diet related discolourations occur regularly in captive birds. It is worth noting that an adult female found dead in Amsterdam NH in September 2004 – generally regarded as an escape also because there was no invasion of Bohemian at that time – also had a pale tail band (van der Vliet et al 2005). Finally, this bird was an adult male, which is only the case for a very small minority of vagrant passerines. Adding up all these points, the committee decided that the interpretation that the pale colouration was caused by inadequate food supply in captivity is more likely than a wild vagrant with an aberrant tail colour. Annual Report 2019.|
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