Thursday, 18 April 2019

Blenheim Bonaparte's

Bonaparte's Gull has something of a history in spring in Oxfordshire. Indeed if you look back at past records they have all been in April or May:

Farmoor, April & May 2017
Farmoor, April 2009
Farmoor, May 2007
Farmoor, April 2006
Farmoor, May 2000

So perhaps it shouldn't have been too much of a surprise when Nic Hallam (not for nothing is he called the "Gull Whisperer") found a wonderful adult Bonaparte's Gull on Blenheim Palace Lake a few days ago. Having seen the last two county birds I wasn't in too much of a hurry to go and pay my respects but instead waited a few days until I had a convenient break in my work schedule. Since my family are quite partial to a visit to Blenheim themselves we decided to make a family outing of it. Thus whilst they wandered off to visit the butterfly house and to ride the miniature train I headed off catch up with what would be my third county Bonaparte's.

As I was heading off towards the central bridge that divides the lake into the Queen's Pool to the north and the Lower Lake to the south I thought I'd better catch up on my RBA texts. To my consternation there was a message saying that the Boney's had last been seen at 1pm before flying off high to the south. That didn't sound too promising. It was now 2:30pm, had I managed to come just after it's final departure? Actually I needn't have worried: I arrived at the usual viewing area (south over the bridge then turn west and walk down the slope to view the Lower Lake - see here) to find a couple of birders there who informed me that the bird had returned a short while ago. Relief!

Viewing conditions were pretty terrible: we were looking into bright hazy sunshine and the bird was either flying around between us and the old boat house or resting on the water on the far side of the lake. Having read several other blog posts on the matter, I realised that I'd forgotten to bring the all important bread that would lure the gulls in close enough to get a good look - doh! I therefore had to content myself with scope views which were adequate but not exactly crippling.

Bonaparte's Gull is very much a birder's gull - it has a number of subtle difference compared to our Black-headed Gulls (which were also present today). In flight the most obvious feature was the lack of dark underwing primaries. BHG has P8 to P4 quite dark on the underside, giving a dark tipped look in flight whereas by comparison BG is strikingly pale. One would also regularly get glimpses of the lovely bubblegum pink legs as it flew around which was an instant diagnostic feature.

Blenheim Bonaparte's Gull in flight - pale P8-P4 & bubblegum legs, courtesy of Roger Wyatt

Black-headed Gull - note the dark P8 - P5 undersides, from the internet (c) original photographer
When settled on the water the usual diagnostic feature is the slimmer all dark bill compared to the chunkier more deep blood red colour of the BHGs though in the hazy light and at a distance this wasn't always obvious. The hood of the BG was also darker than the rich chocolate colour of a BHG and extended further down the neck though this can be misleading as the extent of the hood does depend on posture. One of the other birders also pointed out that when resting the BHG's generally had a longer necked look to them compared to the more compact jizz of the BG though you can't see this so much in the photos below as the BHG is in loafing mode.

Floating Blenheim Bonaparte's - slim dark bill, dark hood extending further down the neck, courtesy of Roger Wyatt

Black-headed Gull - chunkier deep blood red bill, chocolate hood that doesn't extend down the neck
(c) David Hastings,
Aside from the gulls there was a drake Mandarin, a couple of Common Terns and the usual water fowl that one might expect. As I made my way back up to the bridge a flock of 25 Sand Martins flew in, swirled around the bridge for a few minutes before heading on their way. I checked the island on the Queen's Pool which had a bunch of nesting Grey Herons and at least 6 Little Egrets but no Great Whites. There were also a couple of Shelduck on the Queen's Pool.

Having had my fill of the Boney's I met up with the family and we rewarded ourselves for our respective endeavours with a nice tea in the tea rooms before heading back to the car and home.

Video courtesy of Badger

Courtesy of Roger Wyatt

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