Sunday, 7 January 2018

Just published: 'A guide to not birding the North Kent marshes'

Mid-winter, and the birds can be struggling in even the best weather.

A high tide middle of the day means little time when the mudflats are uncovered in daylight; even though waders can feed at night, their sight is impaired (so the likes of Plovers change from visual hunting to less successful blind probing) and blind probers are more spread, often away from optimal edge feeding (mass escape flights a lot harder, better to be in smaller groups).

That's not today. BBC weather has low tide 10:30, Birds are okay. Aren't they?

Some adjustments are needed. First, to the excellent NTSLF site for the surge forecast:

Looking at the 7th, a bit of a surge during the morning, but that peters out by the time the tide comes in. Shouldn't be a problem? A need to visualise that information on the tide details:

Suddenly, not as much feeding available. Firstly, the low tide level not quite as low- mid-estuary, some of the feeding areas reached by the waders that follow a tide out will not be uncovered. Birds that like to stay by a tideline edge do so because their prey much less active during uncovered periods, especially as the water drains out of the mud. They might even burrow deeper. So birds lose out on this.

Secondly, the lower flats out mid-estuary, those that cover by about the 2.5 metre mark, aren't available for as long as could be; the birds will be moving back in and packing the shoreline flats earlier. Overcrowding isn't good. Example, some prey can 'feel' movement above/around them (why Plovers watch from a distance, then dash in) and a few hundred clockwork calidrids dashing about early cause them to go deeper. Feeding conditions are worsened (and, remember, the menu is getting barer now as prey is depleted, plus the birds need more food to get through the poor weather).

Next, it's a Sunday. The great British public are out in numbers. More chances of bird scaring. The waders can't count on those later covering flats being available right up to covering.

Plus, the weather. A quick check of the inshore waters c/o the Beeb, because those winds on your onshore forecast are always down on the estuary actual.

Aww, that's not good. Strong winds really cause feeding problems for some species. A large number of the Redshank will hunker down in the cord grass rather than wobble about, losing body heat. And prey can sense it, can sense the mud drying quicker, down they go earlier.

Still at least it's not raining. Raindrops coming down on mud really mess it up for visual feeders.

So, I'm still typing this, in my jimmy-jams, hot cup of tea close-by. Because not worth borthering the birds much at the moment. I want them to feed. There are no sanctuaries on the estuary, people will be out causing disturbance from the open sections of the sea wall (many inadvertently I hasten to add), people will be out along closed sections carrying out whatever they have to. Me going to either, standing, staring, will only add to it and I can do that under better conditions on a less crowded weekday. Let 'em feed.

Of course, once the tide is in, still problems. High spring tides such as we've been having can cause the birds to have to use sub-optimal roosts. Seen tweets and postings this week where locals have been saying 'birds trying to roost on seawall, but disturbed by x'. More energy wasted. I try to pick my spots carefully on such days. Today is a moderate spring, without a surge over high tide though? Look at that wind speed. The state of the estuary waters, by my own terminology, will be 'flippin choppy'and there'll be a lot of waves breaking on the islands- many relatively safe roost sites won't be.

All in all, a very uncomfortable day for the waders (and the wildfowl) out there. So I'd be tailoring my behaviour accordingly to give them a little peace (birders are one of the main causes of wader disturbance, after all). Nope, my post-op recovery needs are a nice excuse to stay off the wall anyway. There's always tomorrow.

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