Monday 24 April 2017

Bonaparte's Gull-a return visit 24th April 2017

What a difference in the weather today. Gone was the sunshine and blue skies of Saturday to be replaced by grey clouds and occasional rain  brought on a northerly wind.

Having had such success with the Bonaparte's Gull on Saturday I ventured out for another encounter, reasoning that this was an almost unique opportunity to observe this rare North American gull at close quarters and one that should not be passed up.

My knee is slowly healing so I managed to make the short walk from Lower Whitley Farm and up the steps to the southern side of Farmoor Two reservoir where the Bonaparte's appears to be currently settled, and sure enough, once I was on the perimeter path, I soon saw it patrolling along the edge of the reservoir.

Unlike Saturday, when it remained mainly on the water, it spent much of its time today airborne which gave me a thorough testing in taking flight shots, some reasonably successful but as usual the majority not, but practice makes perfect! I do find trying to remember to make all the different technical adjustments to the camera as the light and the birds position constantly changes so burdensome and frustrating.

Anyway enough of my grumbles, it was still an overall happy and positive experience watching the gull as it flew over and above the Great crested Grebes, waiting for one to bring a small fish to the surface so it could make a flying grab for it from the unsuspecting grebe. Today it was not so successful as two days ago, although it did manage to find a couple of fish floating on the surface of the reservoir, possibly abandoned by a grebe. It would still occasionally fly to a grebe and sit near it more in hope than expectation but soon would take to the air again and patrol a small area of  about three hundred metres along the southern wall, often rising quite high in the air before flying down to water level. It was noticeable that it always remained in the general area where the grebes were feeding as did the half a dozen immature Black headed Gulls with which it was loosely associating.

Although superficially looking similar to a Black headed Gull they are smaller, with slightly shorter wings, a delicate black bill and in flight are more elegant, some say tern like, and indeed the underside of the outer wing is pure white with a black trailing edge similar to that of  Common  and Arctic Terns. 

Today there was ample opportunity to compare its tern like characteristics as at least fourteen Common Terns were also on the reservoir and, coming as a pleasant surprise, so were two Black Terns.

The Bonaparte's tired of flying around and landed on the retaining wall where it picked up, separately, a couple of small fish for which I can advance no explanation as to how they came to be on the wall. These fish were relatively large for such a dainty gull, possibly they were not the usual sticklebacks but they went down its throat in one motion nonetheless, although not without some effort. This resulted in the gull's crop becoming visibly distended. 

The Bonaparte's Gull has just eaten one fish and is about to tackle another
despite appearing to be stuffed full - hence its bulging neck
Note the distended crop!
After such a surfeit of food this then required some quiet time to digest the fish so the gull flew to sit on the water but not for long. Soon it was back on the wall again, this time walking along the top picking off flies and invertebrates as it went.

It was hard to remember that this gull is such a comparative rarity here and I found myself wondering if this is how they behave in their native North America.The last time I saw a Bonaparte's Gull in North America was as part of a compact feeding flock of hundreds of individuals, behaving very much like terns, far out to sea on a whale watching trip, off Venice Beach in southern California during late summer. In the breeding season they form small inland colonies across the northern USA, Canada and Alaska, nesting mainly in trees near lakes and then migrate southwards to the coast to spend the winter.

Watching this gull I could but marvel that such a small and delicate looking bird, that had been raised as a chick in a nest in a tree in North America or possibly even further north had crossed to the American coast and then been swept up in a storm that took it right across the Atlantic wastes to Britain, only to find its way to mundane Farmoor, but this is the romance of birding and the wonders of endurance and chance that it reveals

Five of this delightful gull have now been recorded in Oxfordshire, all from Farmoor, the last, before this latest individual, being in 2009. Currently there is a mini invasion of Bonaparte's Gulls in Britain with at least three present, our one in Oxfordshire, another in Essex and yet another in Hampshire and all appear to be of a similar age i.e in their second year of life.

Some men in power boats arrived from across the reservoir to do some maintenance on a pontoon nearby with the result that the Great crested Grebes left the area and the Bonaparte's Gull duly followed them, so I accepted it was time to go. 

Just to remind me of Spring a pair of Greylag Geese proudly shepherded their newly hatched golden young along the concrete apron at the waterside.

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