To coin a phrase that my dad and I use when out birding, I feel that any wader seen in Northamptonshire is “worth the entrance money”. Hollowell Reservoir has a good track record of attracting waders, particularly on migration. Here are some of the highlights from this autumn’s passage season.
Autumn passage started on June 24th (midsummer’s day, on some calendars at least), with the classic late-summer inland wader sighting: a Common Sandpiper on a dam, flicking away on characteristic bowed wings, giving the familiar piping call.
The next day brought a Green Sandpiper, the first of the year for me. A week later, 37 Lapwings were assembled around the feeder stream. On July 6th 3 Little Ringed Plovers were on Guilsborough Bay Point and, on July 8th, my first Dunlin of the year. On the afternoon of July 18th, I watched a lively and characterful trio: 2 Common Sandpipers and a Green Sandpiper, moving along the feeder stream.
An evening visit on July 19th brought a Redshank (surprisingly, a site tick for me) and 3 summer plumage Dunlin, feeding on Guilsborough Bay Point.
A visit on the afternoon of Friday July 31st was notable firstly for high temperatures, in fact this day proved to be the UK’s third hottest day on record, with temperatures hitting 35°C in Northamptonshire. 6 Snipe, the first I’d seen since winter, were surprising and incongruous in the conditions. 4 Green Sandpipers proved to be a peak site count for the autumn period.
An evening visit on August 4th: a juvenile Dunlin flew along the shore from the feeder stream before settling and promptly falling asleep, hunkered down near Guilsborough Bay Point.
August 7th, Lapwings again showing well. Thereafter sometimes present, sometimes not, usually gathered around the feeder stream, or in flight over the reservoir and adjoining fields, with numbers building through the summer and into autumn, peaking at 60 birds by end October.
On August 10th a confiding juvenile Dunlin, perhaps the same bird as the one seen on August 4th, gave close views in lovely evening light.
Evening of August 12th, it felt like a storm was brewing, so just a quick visit. The changing weather seemed to have brought some new birds. As I arrived, two Oystercatchers flew from Guilsborough Bay, landing on the point. Scanning the bay from there I picked up an adult Greenshank, resting among the shoreline vegetation.
The Oystercatchers were still there next day (and in fact for a few days more) but the Greenshank had moved on. This proved to be the only one I saw at Hollowell this autumn, in what has so far been a rather poor year for this species in the county. Murky and humid next day, a Green Sandpiper first heard circling high overhead calling repeatedly, it then settled near the point, 3 Common Sandpipers were also present.
Tuesday August 25th brought further changes in the weather as Storm Francis battered the UK, with gusts of 55mph reaching inland locations, including Northamptonshire. Thinking that the storm might have brought something interesting, I ventured out after work. With a SW wind roaring through the conifers I made my way from the sailing club to Guilsborough Bay Point. The reservoir and surroundings seemed strangely birdless, even allowing for the conditions. Through the bin’s I picked up a medium-sized, stocky, grey/white wader battling towards me into the wind, tacking across the feeder-stream end. Buffeted by the wind, it landed briefly on the Point, close enough to identify it as a juvenile Knot. After landing, the bird preened vigorously for about 30 seconds, then headed off south, not to be seen again. A site tick and in fact my first inland Knot: worth heading out into the storm for.
I continued from there to the feeder stream, where a Common Sandpiper flew out towards the main body of the reservoir.
August 31st. A marked contrast in the weather. An early morning visit in calm, still conditions. Heading across the dam, I could hear a Redshank calling loudly, the sound echoing around making it hard to locate. Eventually found it in the small bay just north of the dam spillway. I continued and completed a productive circuit, with 2 Ringed Plovers and a Dunlin present.
Another early morning circuit on Sep 6th. A tantalising view of an unidentified wader, seemingly flushed near the sailing club, seen distantly and briefly through bin’s from the Point as it flew fast up and down the western shoreline, before flying off high west towards Guilsborough. Jizz overall was Tringa sp, but seemed less ‘contrasty’ than Green Sand. Alas, couldn’t hear a call. Went later that morning to Ravensthorpe Reservoir on the off chance I could relocate it, but no luck, so will have to go down as unidentified.
Sep 8th, an evening visit: delighted to get great views of 2 juvenile Ruff, very mobile, flying between Guilsborough Bay, the SE corner near dam spillway and the western shore, where they fed among a large pre-roost flock of gulls and geese. A site tick for me.
Sep 10th: 2 Snipe near the feeder stream, they’d seen me, but stayed low rather than taking flight.
On the evening of Sep 17th, 5 Dunlin dropped onto the point. With water levels dropping, cooler conditions prevailing and the season advancing, it was starting to feel like a second wave of autumn passage could be round the corner.
Sep 18th I arrived at Hollowell Reservoir at 1720. The weather was fine and bright, with a brisk NE breeze which had been blowing for much of the day.
Making my way to Guilsborough Bay Point, I watched two juvenile Ringed Plovers for a couple of minutes. There being nothing else of interest on the point, I then moved west behind the bay to get the low sun behind me so I could check that area for waders. While there, I heard a ‘shreeep’ call which I identified as a Dunlin and through binoculars picked up what I believed was a group of 5, flying quickly over the water beyond the point, where they appeared to settle. I moved back to my original location at the edge of the meadow where it joins the point. Looking along the shoreline I could see, in silhouette, a small group of waders moving along the water’s edge. I could immediately see that there was a clear difference in size between one bird and the rest and knew I was looking at two different species. The birds moved towards me, going in and out of sight in the low vegetation along the shore. As they did this I could see 2-3 Dunlins in various forms of plumage: 1-2 juveniles, and one which appeared to be moulting into adult winter plumage. As the group got nearer, the smaller bird became clearly visible. From its small size (2/3 that of the Dunlin), short, fine black bill, black legs and prominent white ‘braces’ on the upperparts, I identified the bird as a Little Stint.
All five birds then flew briefly out over the reservoir, giving good flight views, before being lost to view for c10 minutes, after which they reappeared just north of the point, moving back towards me, where they fed alongside the Ringed Plovers.
Returning next evening, I relocated the Little Stint, now on eastern shore, feeding with the 2 Ringed Plovers. All three very confiding, allowed close views, they were still there when I left for home – and were seen next day by other birders.
Not a ‘mega’, but a great patch tick, in fact a county tick for me – and as I write, and as far as I’m aware, the only county record in 2020.
I later checked photos of the 5 Dunlin seen on 17th, in case I’d overlooked the stint on that day, but original ID was correct, so next day was either a separate party of five birds, or one Dunlin had moved on and been replaced by the stint.
October 18th. Returned to the patch after a couple of weeks away. An anti-clockwise circuit, with things seeming very quiet, so I was pleased to find a Black-tailed Godwit among the Teal and Black-headed Gulls on the shoreline of Guilsborough Bay.
I’ve seen Avocet, Grey Phalarope, Pectoral Sandpiper, Grey Plover and Curlew Sandpiper over the years at this site. Other waders recorded here include Sanderling, Temminck’s Stint and, I believe, Purple Sandpiper. Overall a great track record for a small landlocked site which doesn’t appear to be on a major migration ‘flyway’.
In summary an enjoyable period, with plenty of interest, usually something that was ‘worth the entrance money’ – and a couple of undoubted highlights. 14 wader species seen, out of a total of perhaps 17 recorded in the county during the period (I’m still collating full and final records as part of my work as county bird recorder).
I also missed a few birds this season, seen by others, most notably a Pacific Golden Plover, which flew over calling on the morning of August 9th, heard well by the observer but in his view not seen sufficiently well to provide the details required to get the record accepted by the BBRC.
Before closing, I thought I’d mention a couple of factors which I feel may play a part in the productivity of Hollowell as a wader-watching site.
Mud – or lack of it?
Local birders will often grumble about the lack of exposed mud at local wetland sites, and I’m no exception (reminding myself of course that this site’s purpose is to provide drinking water). Water levels at Hollowell Reservoir are certainly variable: in recent years there have been prolonged periods of very low water and also long periods when the reservoir is brim-full, no doubt corresponding to the extended dry and wet periods that have been a feature of recent years. 2019 saw very low water levels in late summer, which brought large numbers of waders, including a peak count of 20 Common Sandpipers and up to 7 Greenshanks present in August. This year saw water levels fall steadily through the summer months, presenting a reasonable amount of exposed shoreline, although this did not provide much actual mud, see below.
Invasive Aquatic Plants
Hollowell Reservoir appears to have an advanced infestation of Crassula helmsii, New Zealand Pygmyweed (or Australian Swamp Stonecrop): an invasive species which now dominates most margins of the reservoir. This would appear to be disadvantageous for waders, most of which of course prefer to feed on areas of mud which is either exposed or submerged in shallow water. My observations here are just anecdotal, but I believe that this infestation reduces the suitable area of feeding habitat. It certainly changes the nature of the habitat from its normal condition and appears to have an impact on plant biodiversity. I believe C. helmsii is extremely difficult to control, so perhaps it’s best to try to find a positive, one being that birds such as Yellow and Pied Wagtails benefit, there were reasonable counts of both throughout the period, often feeding on invertebrates living among the mat of vegetation.
While the bulk of the autumn wader passage is now behind us, there’s still the hope of a late straggler, or an interesting winter visitor (Jack Snipe, Whimbrel or a Bar-tailed Godwit perhaps?), so I’m hoping to be back as often as I can over the rest of the year.
This blog post describes birds I’ve seen myself during this period, all opinions expressed are the result of my own observations rather than scientific study. All photos are my own. Thanks for your interest.
Hollowell Reservoir is managed by Anglian Water, access by permit, available from Pitsford Water Fishing Lodge, Holcot Road, Northamptonshire.