22 Mar 2015

22 Mar 15 - Vis Mig Produces A Harbour Tick

With the partial eclipse of the sun on the 20 Mar, there has been a close alignment of the sun & moon. The result is there has been incredible set of strong tides over the last few days. With the size of Poole Harbour, holding such a large body of water, there is a lag in time the water takes to leave the harbour & so the low tides never get down to a low tide of 0 metres. Looking at tide tables over the last few years, I don't ever remember the lowest tide at the harbour mouth ever getting lower than 0.3 metres in the tide tables. But this weekend, the lowest tide was a mere 0.06 metres. Correspondingly, there has been the highest tides I've seen in Brands Bay.
Low tide at Brands Bay: (21 Mar 15)
In the last couple of weekends, I have neglected the South Haven part of Studland, in favour of looking for early Black Redstarts & Wheatears in the Old Harry & Greenlands Farm parts of the patch. So this weekend I planned to spend some time at South Haven. The Saturday was fairly uneventful, except for a light Northerly wind which produced a small Northerly Visable Migration (Vis Mig) of mainly Finches across the harbour mouth. Birds like to fly into the wind at low level as they gain lift, which is the same reason that areoplanes pilots prefer to take off into the wind. The highlights were 50 Chaffinches, 5 Meadow Pipits, 2 Bullfinches and singles of Goldfinch, Siskin, Linnet, Reed Bunting & Pied Wagtail. This would be a quiet half hour in the peak Vis Mig month of October, but was good for an early Spring day. There were also 4 Long-tailed Tits that tried on several times to get across the harbour mouth, but despite calling a lot to egg each other on, they never got more than 20 or 30 metres before giving up.
Low tide at Brands Bay: The circular marks aren't a type of marine crop circles, but they are the after effect of the damage that shellfish boats do to the seabed as they spin around & around. They aren't allowed in the inner part of Brands Bay, but some of the boats ignore the rules (21 Mar 15)
Given the Saturday Vis Mig, I decided to give it another go on the Sunday morning, but the news was there didn't seem to be anything on the move before I arrived. I ran into local Birder, Steve Morrison, who spurred on by my news that the Stanpit Birders had seen five Garganey's that morning was tempted to join me to check the South Haven pool. We spent some time checking the pool, but no joy. Then a very large, bulky Accipter flew low over the pool about 30-40 metres from us. This caused panic alarm calls from the local Carrion Crows, which did nothing to fly up and challenge it. We both noted the very large, bulky appearance, deep based wings & long tail. It was larger than the largest Sparrowhawk I've seen. I took it the four or so distinct dark bars on the uppertail, whilst Steve got onto the streaky breast. In less than 30 seconds it had disappeared out of sight. Five minutes later it flew back low over the pool, reinforcing my impressions of the first view & causes the same disapproving alarm calls from the Carrion Crows. As it disappeared, I shouted to alert Steve, who was now on higher ground at the edge of the dunes. He picked it up, as it turned North & out over the harbour mouth and then Brownsea. Going back over the views, we were fairly certain it had to be a male Goshawk: a surprisingly rare Bird in Dorset. I suggested we head back & doublecheck Killian's Collins guide in the car. This confirmed the streaking indicating it was a first winter individual & the size made it a male:a Poole Harbour Tick. News went out at this point on the local Birders email, but I didn't make any further attempt to ring the news out as it was already long gone. So no Finch Vis Mig, yet proof that a Vis Mig watch on an apparently dead day, might still be worthwhile on other days. I have always been sceptical about a number of single observer Goshawk claims in Poole Harbour, given the observer's beliefs that they are commoner locally than they are. I have always thought they are at best a rare species which is a short distance migrant or wandering species within the UK. I was pleased to have had Steve with me, given the Canon 7D was in the car & the SX60 isn't a good camera for reacting quickly for action shots.
Coot: No chance of Goshawk, so I will have to fill this Post up with the news the Coot (my only February patch tick) is still at South Haven
After a celebratory coffee, we decided we should try the Eastern Lake as clearly the Garganey would be there. It's a longer walk from South Haven, but there was the chance the Redpolls that had eluded me all year, might be back in the area: but no joy. However, as we got close to the Eastern Lake, we put up a Jack Snipe from a small wet patch. Although, it looked to come down fairly close to us, it landed out of view. So no chance for more views. This was the second totally unexpected species for the day. Jack Snipe is a very scarce, but overlooked, species at Studland with my only other sighting being three in Brands Bay on 8 Jan 10 during a hard Winter spell. To top off the morning, the Great White Egret was on the Eastern Lake again. Hopefully, it will remain for our final WeBS count this coming weekend.
Finally some high tide pictures from Brands Bay
Even on the highest of normal tides, there are a line of islands dividing the inner bay in two (from left to right): Not today
So unfortunately, no photographs of the two patch goodies from the weekend. I had hoped to get to 130 by the end of March for the Studland/Ballard Year List. These two goodies got me to the 130 mark, without managing to see any early Hirundines, Blackcaps or the elusive Redpoll. There is still a final weekend, when I might get past the March target. There is only fifty species more to reach my end of the year target.

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