White-billed Diver

White-billed Diver aka Yellow-billed Loon Gavia adamsii is a species that has been near the top of my wish list for several years with little expectation of ever seeing one. It is the largest of the five Diver species, breeds in the Arctic and winters along the coasts of the northern Pacific Ocean and north eastern Norway. It is however a vagrant to the UK and when the opportunity came for a friend to meet me at Grantham station and take me to see the bird which has been on the River Witham for the past ten days, it was too good a chance to miss. Fortunately, it was still at the same site for the eleventh successive day and gave remarkably close views.

This is a juvenile bird and all the major identification features of this species can be seen in this photograph. The bill is very large with a pale tip becoming darker at the base, the sides of the neck are pale and it has a very pronounced bold scaly pattern on the back. The top of the head is flat and similar to Great Northern Diver and the bill of the juvenile is held horizontally. The adult in breeding plumage is a stunning bird which holds its bill pointing upwards.

The bill colour is white or yellowish in the adult which leads to a slight confusion of names. Loon is the commonly used name in North America and the current internatonally recognised English name is Yellow-billed Loon although I am of the old school and have a preference for the European name of White-billed Diver.

References: Wikipedia; Mullarney, K. and Zetterstrom, D. (2009) Collins Bird Guide 2nd edition pp 62-63.