Thanks to volunteer Phil for his report and photos.
Sitting in Nettley’s Hide eating lunch I became aware of a small group of people with scopes in the hide discussing a distant raptor perched on a post. I was overhearing comments about a back turned towards the scope but occasionally barring could be seen across the breast. Sparrowhawk and goshawk were mentioned and rejected although my first thought about a barred breast had been a peregrine. I picked up this bird in my binoculars, but it was too distant to identify, and I resolved to take a closer look on finishing lunch.
Setting up my scope later the bird had its front towards me and the barring on the breast was very prominent as shown in this photo.
Other obvious features were yellow legs and a yellow patch on the beak and some dark brown plumage.
The more I looked at this bird the more I concluded that it was a common buzzard, based on size and the general colour of the plumage – a mixture of brown and pale - and the leg and beak colours. I could certainly understand why the visitors briefly speculated about goshawk as this is a similar size and colour and always exhibits barring across the breast. Eventually it flew and gave me the classic showing of the underwing pattern of a common buzzard as in this photo taken a few years ago.
However I cannot recall seeing one with such prominent barring across the breast before.
What this illustrates more than anything is the extraordinary plumage variation in the common buzzard. This has certainly caused confusion to birdwatchers in the past and many less experienced people assume that buzzards are just large brown birds of prey. I recall one occasion when a very pale buzzard was reported as an osprey just because of the pale colour. Ospreys are only very rarely seen at Pulborough Brooks and nearly always flying over on migration when the Arun Valley is sometimes used as a flyway. I have never seen one perched here.
This encounter prompted me to look back through my buzzard photos from Pulborough Brooks. One pattern often seen is a pale broad ring feature across the breast and I have occasionally wondered if this might be a local West Sussex variation. On the other hand it could simply be that I was looking at the same bird!
And here are 2 more photos that showing irregular pale patches on the plumage.
Although the underwing pattern is usually fairly constant, even that can vary as this photo demonstrates.
The French name for a common buzzard is “buse variable” and somehow this seems much more apt.
Notes:
You can find out more about the buzzard on the RSPB's 'Bird A-Z' here.
Here's the sightings board from the weekend which included sightings of Kingfisher from Nettley's hide on both days (and of course at least one of Phil's buzzards).