Forget the fifteen minute rule

One of those days where the wind whips the scope over. But one of those days where the birds are having it much worse than you. Forget all the feeding drivel from yesterday's post, today was just about holing up. The surge arrived just after high tide, so the 6.3 only became about a 6.5, but wave height was enough to cut off Horrid Hill, and drench all the roosts; the waders ran for cover, and the diving birds took to the sheltered bays. For sure, the wave action wasn't huge; it never is, but was enough to disrupt normal behaviour patterns. As soon as the waters were dropping, they started heading for favoured sheltered spots mid-river.

So, instead of loafing, and instead of feeding, they were actually flying; just like a real flippin' seawatch. Shame my chauffeur was only allowing me an hour out, but plenty of time to enjoy the Mergansers and the Goldeneye.

Again, the same game as yesterday. A second birder present, I put him on the two drake Goldeneyes that had just flown in. "Out in the channel separating Nor from Friars'. If you look beyong, they're effectively under the end of the Stoke Crossing bridge."

"I can see them. Too far for me."

Again, we had a nice chat on many things, especially numbers back a few decades. But that too far for me stuck. I found myself apologising for seeing them when I chatted with one of the Rangers. "Goldeneye, that's nice."

"Yeah, but too far for most to enjoy, sorry 'bout 'dat." Flip! Apologising for seeing things. Whatever next?

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Last five mins of my recuperative visit saw me scanning Rainham Saltings as they started to reappear. That's where the Great Crested Grebes had come in to ride out the gale. They never get that close in normal circumstances. Books say they hate wind/high waves, and often move when conditions set in. Hopefully tomorrow mornings lull will give them a chance to feed up. Good excuse to count. Again.

The fifteen minute rule

Joined by a birder for a very short stay at the end of Horrid. You know the sort. Say they're a 'regular'. Come here two or three times each winter. They were in the mood to tell me all what was out there. Made my mood a mite mischievous, especially when he hinted at the estuary always being a bit, well, "dull".

"Not much to see here though. Twenty-three Greasies. That's about par for the course for me here."

"Forty-seven." I replied

Pause. Counting noises. "Well I can manage twenty-four. Just"

I smiled. "You counted that stretch in under three minutes. I usually take fifteen, because the distance between the two points is fifteen fields of view in my 'scope, you really need a minute for each.Also lets you get your eye in for any distant birds"

Stunned silence. So, I fill it.

There's more chance of the bird being under than on the surface at the mo'. They're feeding on shoals moving up with the tide. Now the average Great Crested Grebe dive length is under for thirty seconds or less; but they might stay on the surface for much less than that.  So, watching each field of view for a minute means you should get them on the surface before you pan left and repeat (though you will still miss the odd one that swims submerged between fields).

"Seems like hard work to me."

"It is. The bad news is if you're checking for Great Northern Divers, they can routinely be under for up to a minute as a rule. Red-breasted Mergansers? Bit of a bummer, up to thirty seconds the norm, but they can chase prey for up to about the two minute mark. And they can move between fields a lot. Only found a couple out there so far, and only seen a couple of times. Goldeneyes are easier though, they're usually only about twenty seconds a dive."

"Haven't got time for all that." was the short version of their reply.

"Didn't think I had, either, when I started birding here all the time. Problem is, all these sorts of species are mainly seen here on the water. You can't really get by with seawatching tactics. These birds made an effort to come into the estuary, now they're here, they're settled. Little need to fly anywhere."

The regular birder went his way. I was sure he muttered twenty-four as he went. Nice chap. I made a mental note to explain how the true number was even higher than forty-seven, because some loafing birds had already drifted away into sheltered creeks such as South Yantlet. I'm really sure he'll appreciate more useless tips from me.

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Well, the conversation didn't exactly go like that, much more civilised, wouldn't have made a good read. But the important point was taking a count as Gospel. If someone doesn't like identifying distant birds, then counts will be low, and that is often the case for occasional visitor counts you see from around the estuary. That knocks quite a few off the total, then missing the feeding birds adds to the difference. Birds might dive for half-a-minute but that doesn't mean they're up on the surface for half-a-minute; small grebes might only be up for less than ten seconds before diving again; why some birders can never turn them up. While at the same time avid readers of social media start to think those lower totals are really what is there. As with the spin in the opening preamble, don't take everything you read as Gospel. Count for yourself.

'Birds of the Western Palearctic' has sets of average dive times for most species, often differing based on depth of water being utilised; the following table is my own rough and ready calculator based on those tables, the depths the birds frequent here on the Medway over the high tide and my own timings. The list has all the commoner diving birds, but that doesn't mean they're all here- one I haven't seen here for about three decades. The main thing is it might inspire some to think about such things.

One of the best B.W.P. entries is for Great Northern Diver. Studies have shown they can spend excessively long times under- up to eight minutes. But these longer periods were not thought to be due to feeding behaviour, more likely an evasive/escape behaviour when feeling pressured. To date this winter no reports from the old Docks basins, but they have been reported via Birdtrack, so only a matter of time and a good blow I reckon, then it'll be interesting to record how long dives are there, and how often the longer ones actually see bird(s) coming up with prey. Just feeding or evading birders? Something to brighten up a dull day. The more you read, the more you want to check things out.

What's the F U in Ham Ooze? (Boris Waters, part four)

Towards the end of August I can always guarantee seeing at least one other birdwatcher out and about Ham Ooze. This individual will usually be on his boat, scanning the mudflats, looking in towards Ham Creek.

Scanning for duck, August 2015

I saw him out on there on the 20th and 30th August this last year. He always kept his distance from the shore, making sure he didn't disturb any duck that might have already returned to this part of the estuary. The date for the start of the wildfowling season is pretty much bang on- first numbers have usually arrived by September, and this local wildfowler knows how to check up on the Greenborough/Slayhills/Burntwick dabbling duck numbers for the start of their season; do not bother checking the islands themselves, simply check (what ornithologists call) the optimal daytime areas of the Functional Unit.

A Functional Unit (or Core Area) is, for a duck, all of the habitats used routinely during any 24 hour period. Think of it as being like a nesting territory, but without a nest. For the majority of (well-fed) dabbling duck, daylight hours are spent loafing. It makes sense to carry out much of your feeding at night, spread out among the islands, saltings, marshes and fields, when predators are less likely to find you. Then you simply rest up by day- safety in numbers, always a few birds in the flock alert for predators and similar threats (such as human recreational disturbance).

Ham Ooze, distant wildfowl and waders, September 2013

And for this part of the estuary, the main loafing area is where Sharfleet Creek turns south to merge into Ham Creek.

The main named areas within Ham Ooze

The reasons for choosing Sharfleet/Ham are fairly obvious; a fair depth of sheltered water, even on low tide. More open views than will be found inmany of the other creeks around the islands. On the flood the majority of the birds can simply drift in towards Millfordhope Creek and not waste energy flighting from one area to another (avoiding the guns)- and they remain a sizeable distance from observers on the mainland at all times. Finally, the Ooze is not an easy area to navigate, only possible for boats with a shallow-draft on the highest tides, so they are rarely bothered by pleasure craft. It is a true wildfowl refuge.

Ham Creek Wigeon moving into Slayhills/Millfordhope, September 2013 

Hungrier duck will also continue to feed in the loafing area as well as along the tidal edge of Half Acre and the small creeks, where tidal action will be stirring up plant seeds. Numbers also cross to and from the freshwater pond on the edge of Bayford Marsh to drink and bathe.

Marsh Harrier putting Wigeon to flight, Slayhills, October 2013

At the right time of year cumulative totals of Wigeon, Teal and Pintail can routinely run into four figures. And that will be only what can be counted easily at a distance; undoubtedly birds are often missed. The birds have chosen an extremely safe area for this part of their functional unit.

Wigeon, Ham Ooze, October 2014

The Medway Estuary gets scant coverage here by birders because it is remote and the birds are distant. Public viewing is only possible from the Saxon Shoreway footpath at Shoregate Creek. It is an area for which even I have few photos, though I'm usually happy with 'speck-shots'. But the spectacle of thousands of wildfowl and waders is always enjoyable.

Part of Ham Ooze tideline, September 2013

Whilst not too many duck make the journey to mid-estuary and the likes of Bishop Spit, Brent Geese can often be seen there. The Spit appears to provide good feeding, as well as being a gathering point for flocks departing the Medway, remaining popular through to the last departing birds in May. Often where the small number of over-summering birds can be picked out June to August.

A distant gathering of Brent Geese, Bishop Spit, May 2014

Shelduck also gather in large numbers about both areas, especially late winter. In the summer, the goose interest is more 'feral', with the local Canada and Greylag Geese flocks often to be found swimming between Nor/Friars and the island complex. They are likely not to be able to move out of the way of any seaplane very quickly, being they use these waters are their safe area during their full wing moult when they are unable to fly. (One hopes, for safety's sake, any seaplane pilot might recognise these birds won't be able to leave an operational area at any great rate of knots.)

Canada Geese (and hybrid) off Ham Green, July 2015

Offshore, the Half Acre channel appeals to feeding diving duck, with Red-breasted Merganser and Goldeneye often feeding throughout the covering/uncovering of the tide (rarely Eider), rafts of Great Crested Grebe, the odd Diver and scarcer Grebe species. As winter evenings approach, Bishop and Half Acre can often hold five-figure roost gatherings of Gulls. In the summer months Terns often hunt for food for their young, and three-figure counts of Little Egret crisscross the estuary. Ham Ooze and Bishop Spit are clearly important parts of the functional units for many species that rely on the Medway estuary complex.

Little Egret, Ham Ooze, October 2014

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The notification of these seaplane operational areas alongside Bishop and Ham moves ahead next month regardless. Whether Natural England (or RSPB/Kent Wildlife Trust) do eventually raise concerns over recreational disturbance will have to be seen. I hope this short series of posts have given an indication as to why they should.

Shallow divers

The two regular diving duck species on the estuary at this time are Red-breasted Merganser and Goldeneye. The local guide books always mention them, but sometimes visitors leave disappointed. They are not easy. There are never that many of them, and it's a big estuary.

As with any visit, you need to be thinking about the state of the tide.

Both species feed routinely at just a few metres' depth, and follow their prey. High tides can be frustrating. Making/falling tides can be the best bet.

This morning was one of the good days. Arriving at Bloors Wharf just as the water started to ebb from the shore, a pair of drake Mergansers had taken a liking to Rainham Creek. Creeks are often a lure for the fresh water, but they were more interested in feeding. The Creek had been excellent the day before when a Common Seal was clearly catching Flounders with ease, and today must have had small shoals present as the Mergs continued to feed actively for the 90 minutes I watched them.

There was also a pair of Drake Goldeneye, but much further out, on the northern edge of Bartlett Creek. "Adequate 'scope views" in the birding parlance. (That is, if you squint you can just , just, make out the cheek patch. With imagination.)

I returned at low tide in the late afternoon. A mile of mud, but knowing where to squint found the birds settled in the shallow creek separating Nor Marsh and Friar's Saltings. The creek holds a fair depth of water (and food) over a neap low water.

The Mergs continued to feed, but now the Goldeneye were displaying. There were now four, three males and a female. Two males kept tight to the wake of the female, displaying at her all the time. Courtship display.

Intriguingly, among ducks there is a fine line between love and hate. The same movements that make up the courtship display can often be found in territorial defence and in outright aggression.

So what exactly was in the mind of the third Goldeneye was a little harder to tell. He sat just a matter of metres away, busy going through the very same motions, all the head-pointing, the head upending, the bowspriting that the other males were engaged in, but he was displaying at a Great Crested Grebe.

Had the Grebe been fishing too close? Was this pent-up frustration being vented, with the female preferring the other males? Impossible to tell which side of the fine line, but the Grebe remained completely indifferent either way.