Saturday, 4 September 2021

Creeping tide clears the beach!

The breeze still from the east. Overcast all day apart from 30 minutes sunshine mid afternoon.

Middleton Nature Reserve 
Ringing report from Alan:

An improvement in the catch this morning with a small selection of warblers that may have arrived over the night before last. Also caught were three Grey Wagtails. The catch comprised 3 Willow Warblers (+ 1 retrap), 3 Chiffchaffs, 2 Wrens and singles of Dunnock, Cetti's Warbler, Lesser Whitethroat, Common Whitethroat, Garden Warbler and Blackcap.

I had a quick check mid afternoon (MD)

Gadwall just 4 again, no sign of Wigeon

Teal 5 on "no swimming" pond, later flew off to south

Common Snipe 1 flushed from edge of main pond - first record this autumn 


Emperor 4

Brown Hawker 2

Migrant Hawker 4

Common Darter 5

South shore

Rock Pipit 1

Wheatear just 2 along the same stretch and at same time that I counted 37 yesterday!

Again, the objective of today's walk was to check out the waders on the water line out from the saltmarsh, I could see there were high numbers from a distance, but as I got closer most of them flew off south, not a raptor today, and I was nowhere near enough to spook them. It was only when I got closer that I realised what had happened (MD).

The morning breeze was fresher than of late and due east, and the sea was quite calm. The net effect of this is that the wind holds back the waves that would normally lap the waterline. When this happens I think of the tide as "creeping" in. This is what a creeping tide looks like coming up the beach.

Creepy, isn't it! This is what it looks like looking down on it, you can just make out some very slight wave action at the end of this clip.

When waders normally stand on the waterline, it is the incoming waves that force them to move forward. But the wave only reaches one or two birds at a time and the flock tends to shuffle forward following the same wave action (even when there is no breeze at all, there are inevitably still small waves lapping the water line). When it creeps in like this, there is no single stimulus to move, the birds tend to just stand there till the water is higher than they are comfortable with, unfortunately this happens to all the birds at the same time, so when one moves they all move, this then spooks nearby birds. As they fly off they spook all the others further south in a domino effect, that is what happened this morning. 

By the time I'd reached a reasonable viewing distance, the only waders remaining were this group of Grey Plover and Bar-Tailed Godwit. The only reason they were still there, is that they would have been the northern end of the original line of waders. It was obvious that the Plover were as deep as they get without swimming and an exit was imminent. The water looks quite choppy in this clip, but that is a foreshortening effect, the birds were over 5m beyond the waterline.

Best estimate of waders seen:

Knot c600

Grey Plover c80

Bar-Tailed Godwit 50

Dunlin c150

Curlew c50

Redshank 12

Oystercatcher c300

Shelduck 4 juvenile together, no sign of any adult. I'm posting this clip, not so much for the birds, but it does clearly demonstrate how the east breeze was pushing back the waves that normally lap on the waterline.

Mediterranean gulls 8 adult - this was a bit frustrating, I could just make out that this one had a white ring, too far away to read, and as soon as it made its way to join a small group of Meds it promptly sat down. If it had remained stood, I might have tried to get closer, but I decided to leave them in peace.

4 of the 8 Mediterranean gulls roosting on the beach