Natural Selection

After an uninspiring seawatch from Blackpool North Shore this morning I went to the nearby shorebird roost. If you are new to this blog this used to be a boating pool built into the sea defences, nowadays it’s a go kart track. Depending on whether the go karts are doing their thing waders roost on the outer walls or within the perimeter. It’s the only site for Purple Sandpipers on the Fylde coast these days, and during the week a third bird was reported with the usual two.

When I was at University in Lancaster there was a wintering population of a dozen or so ‘Purps’ that gradually began to dwindle. Careful observations showed that they didn’t take evasive action in flight like the Turnstones they associated with, and were disproportionately falling prey to the local Peregrine. They are barely annual there now.

Why am I recounting this? Well despite being predicted to die out Blackpool’s wintering Purple Sandpiper population clings on, and a factor in that is perhaps literally clinging on. In the picture above the Redshanks and Turnstones have stopped feeding with the tide high, but two of the Purps are continuing to feed on the steep sides of the car track. Their ability to ascend such steep slopes presumably gives marginal gains in being able to feed longer.

This isn’t the greatest picture but you can see that both birds are extending their right legs but not their left legs to enable them to balance on the gradient and continue feeding.

I didn’t think the third bird was present but after taking the feeding pictures saw it was among the other waders already roosting. Perhaps it isn’t as confident as the regulars in wave dodging rock climbing!

If you know where to look all three of Blackpool’s current Purple Sandpiper population are visible in this shot. Basically every smaller bird that isn’t a Redshank is a Purple Sandpiper.

Purple Sandpiper (left), Turnstone (right) and Redshanks (above). Although not the best angle to see all the features of the Turnstone well note the more variegated upperparts and the brighter legs not much different in shade to the Redshanks.

If you are local these birds are immediately in front of the old Cabin Lift on North Shore. The best days to look for them are when there is a bit of an onshore breeze, on milder days they roost on the seawall furthest away from the Promenade, when it’s windy they are more likely to be in the position in the opening photograph.