Duck Soup ingredients- (vi) a chinois of Shoveler

Their sieve-like bill makes the Shoveler the most specialist feeder of the dabbling duck, with planktonic crustaceans a mainstay. On the Medway they take mainly hydrobia and some salicornia seed. Through necessity feeding takes place on calm (usually fresh) waters, but is also routine on mudflats, especially on the wettest interstitial mud where prey numbers can be much higher than found in open water- why the Shoveler will often feed close to the footpath at low tide in Rainham Creek towards Rainham Docks East, or just offshore from the Twinney Saltings.

Interestingly, Shoveler often loaf within their feeding zone, unlike most other Anas species which prefer distinct separate areas for loafing.

When disturbed, the majority of birds in the western half make for Friars Saltings or Nor. To the east the Twinney flock tuck into Millfordhope/Slayhills, less often into Funton.

As winter progresses, small numbers spread out and take up with ducks at the other main loafing areas.

In the past very few used the estuary as a feeding area. Now, peaks are usually noted during early winter, after which time poor weather (strong winds on open waters) can see decreased numbers (often reflected by increases elsewhere around the North Kent Marshes). Freezing conditions see birds deserting shallow waters first for the estuary flats, all evidencing why large counts alone might not reflect true carrying capacities.

The main autumn loafing areas are marked on the following map (yellow), together with the two main mid-winter concentrations.

From personal experience, the present five year average peak from WeBS (192) is an understatement of the wintering population. Over the covering/high tide, esturine Shoveler tend to tuck up tightly in cord grass; watch a mudflat loafing/feeding group through the covering cycle and numbers will always be higher when the mud is uncovered. WeBS are high tide counts. A good example why birders on many estuaries around the country carry out co-ordinated low tide counts much more often than the BTO LTC six year survey. Another species where more ad hoc counts by birders can help provide a more detailed picture.

Flighting up times

The last couple of session out have seen me mainly musing on disturbance- specifically, fireworks disturbance.

The tide on New Year's Eve had been covering just approaching midnight, which could have meant a fair number of birds close to shore. The traditional British approach of letting off fireworks from any time up to six hours before the stroke of midnight had already put paid to that. A check the following night (with fireworks still being let off around Gillingham), notched up fewer than expected territorial waders close in, and no sign of any moving flocks. Daytime checks along the urban stretches showed the species that follow the tide in, weren't. Just a few hundred Dunlin. It takes time for these birds to feel the area to be 'safe' again. Wildfowl have also been shaken up a bit; more urban stretches of estuary have seen drops in numbers of the 'loafing' daytime species- some 'feeders' (such as the mud-sifting Shoveler) are nearer normal count numbers. This, to me, is a main driver. Food. Go hungry competing for resources on the estuary, or risk starting to return to an area that had seemed totally alien just a night or so prior. If you have a safe secondary loafing/roosting site, you might stick with that for a while longer.

So numbers should rebuild slowly over the next few days, but how much effect does this disturbance have on the birds at the time? Details on a radar study just over the Channel showing just how many birds are caught up in such things can be found here. Dangers during the panic flights, competing for food resources elsewhere, cautious returns over a few days to territories, all add up.

Of course, it isn't just the estuary birds- as I described last year, other roosting species take fright and flight. One example- a typical December 31st  morning watching local flightlines will see a movement of Woodpigeons from safe urban roosts out into the countryside during the first 90 minutes or so, with a minimal commute in the opposite direction. After that time small numbers start drifting back in. A typical January 1st? Exact opposite. The flight back in, I'm beginning to suspect, might not be the commuters checking the roost site is still there, but more likely the urban Woodpigeon who feed primarily in Medway gardens, returning to their favoured feeding areas.

This would all be well and good if nocturnal mass flights did suffer fatalities (they do) and if having to desert favoured feeding areas didn't put strain on survival (it does, especially in hard weather).

Many birders only notice this through rares- "I hope X hangs on into the New year" (Birders of a certain age, hoping for a revisit for a millennium tick, will remember that Aldeburgh Ivory Gull, last seen December 31st 1999).

If you haven't bothered with the Dutch radar study linked above, I'll draw your attention to one thing- fireworks can only be sold to private consumers 29th-31st December. They can only be used for recreational purposes between 18:00 New Year's Eve and 02:00 New Year's Day. How different to the British approach of starting letting off fireworks days before and continuing well into the New Year (there were more last night here). The recovery period for their wildlife is thankfully short. We just keep banging on and on.

Better get back out and see if 'my' local flocks are back to their 2016 numbers yet.

Over the top

Brent beginning to leave the saltings as the tide ebbs

A changing of the guard. Graham, one of the local WeBS counters, was just packing his gear into the boot of his car as I strolled down the hill towards him. He had, once again, carried out his duties with all due diligence, counting his assigned roost on the top of the tide.

We swapped notes. Clearly Shoveler numbers were still sneaking up, and he had a few of the Motney Avocet pinned down as well.

I said I was planning on counting a tad later. I wanted a count for an area just north of his, which holds and hides a lot of waders on this height of tide, so I'd chosen to watch them off. I realised I was being a teensie bit mean, saying how I was looking forward to seeing a good few thousand birds. WeBS counters are a dedicated bunch of volunteers, and Graham had just worked hard for his smaller numbers, with his birds having sat tight at roost.

WeBS is Wetland Bird Survey, organised by the BTO primarily to assess total wildfowl and wader numbers using the UK during our winter months. When you read in the newspapers of birds like Curlew becoming 'red data listed', or of large numbers of wildfowl no longer visiting the UK, it is down to the work of the unpaid army of Grahams.

Now there I was, turning up to enjoy the same view, different spectacle. This is the fun of an estuary, one person can count a spot, then another come and count said same spot an hour later, and the end results will be vastly different.

We said our farewells and I set off to to beat Graham's wader numbers by a fair few thousand. Hollow victory, the value of his counts beat mine hands down. And I never did get anywhere near his Shoveler number.

Slack tide was past and soon birds were moving off certain roosts to head for emerging saltings closer to the awaited mud. The Dunlin were clearly hungry. They had roosted on Bishop, closest saltings to the deep water channel, and were coming, in flights 100, 200, 300 strong, to claim toeholds on Friars', Motney and Rainham saltings. If only some could land, they did, often seeming to fly backwards in the wind to reverse park, but if part of their flock found no room, then the others would take back to the air with them; they were hungry, but they wanted safety in numbers.

Elsewhere in Kent there have been comments about a lack of Turnstone. Certainly here they have not been at their usual roosts close to shore recently, and I began to wonder if they had moved on, but today I noted the old jetty on the north of Nor Marsh was packed tight. Perhaps their usual haul-outs on the wrecks in Sharp's Green Bay and off of the Strand have not felt safe enough?