The Stanwick ‘Ferruginous’ Duck

It’s not called ‘Fudge Duck’ for nothing. Closely resembling the real thing, hybrids abound, enticing observers into a ticking temptation trap, in which nothing is quite what it seems …

When the news broke of Ferruginous Duck or hybrid at Stanwick GP, at around midday yesterday, it was clearly a sensible move to throw in that cautionary caveat – the dreaded ‘h’ word – as rare ducks are notorious for carrying rogue genes. Although looking good at first sight, this was one such bird which, upon closer scrutiny, clearly did not pass muster. OK, it could be said it was mainly but unfortunately, not wholly, Ferruginous. The following assessment is based upon published images of the bird and follows the most up-to-date ‘hybrid checklist’ of features given by Reeber (2015).

It is assumed the bird is an adult female on account of the iris being dark brown (paler in juvenile/first-winter). In terms of size, it’s too large for a Ferruginous Duck. Two of the images below suggest it is virtually the same size as a Pochard. It also appears too bulky. Ferruginous Duck is small and any bird close in size to, or larger than, Tufted Duck is likely to be a hybrid.

Female Ferruginous Duck-type hybrid, Stanwick GP, 25th January 2020 (Adrian Borley)
Female Ferruginous Duck-type hybrid, Stanwick GP, 25th January 2020 (Adrian Borley)

Head shape is not perfect for Ferruginous Duck and is similar to Pochard. On close inspection, the head shows two slightly paler brown patches, one at the bill base and one on the rear cheeks, which is strongly indicative of hybridisation with Common Pochard. The bill colouration also indicates a hybrid as the pale subterminal mark extends along the sides of the bill, which would form a ‘U’ shape when seen from above. The subterminal mark should not extend in this way (although many published images of so-called ‘pure’ Ferruginous Ducks show it – including some of Reeber’s – so its validity may be questionable). There also appears to be fine traces of black at the bill base – another hybrid characteristic.

Female Ferruginous Duck-type hybrid, Stanwick GP, 25th January 2020 (Steve Fisher)
Female Ferruginous Duck-type hybrid, Stanwick GP, 25th January 2020 (Steve Fisher)
Female Ferruginous Duck-type hybrid, Stanwick GP, 25th January 2020 (Adrian Borley)

The belly is not sharply demarcated as it should be for an adult and it appears a little smudgy. Also, there appears to be a slight demarcation between the breast and the flanks, which is not right for Ferruginous Duck.

Female Ferruginous Duck-type hybrid, Stanwick GP, 25th January 2020 (Steve Fisher)

All the above features exhibited by this bird indicate a hybrid origin. Reeber suggests that hybrids are relatively frequent in the wild and even goes as far as stating that in Western Europe, hybrid-like Ferruginous Ducks are commoner than pure individuals!

Rarity Round-up, 18th to 24th January 2020

With the country sitting underneath a slow-moving area of high pressure for the majority of the week, the weather delivered its own rarity in the form of overnight frost during the first four days. Otherwise, generally mild weather ensued and the range of birds on offer was distinctly narrow – nevertheless new discoveries were made as the week progressed …

The female Ruddy Shelduck, again at Hollowell Res on 18th and 24th, was the closest thing approaching a dapper dabbler this week, while rather more demure divers in the form of Greater Scaup were the first-winter female at Daventry CP all week and the female back at Stanwick GP from 20th to 24th.

First-winter female Greater Scaup, Daventry CP, 18th January 2020 (Angus Molyneux)

Great Egrets remained faithful to Daventry, Ditchford GP, Hollowell, Pitsford Res, Stanford Res, Stanwick and Summer Leys LNR/Earls Barton GP, with a maximum of three at Stanwick on 20th and the same number at Summer Leys on 24th. Summer Leys also produced the first Black-tailed Godwits of the New Year, with two there on 23rd, while three Jack Snipe at Hollowell on 18th and two on 24th ensured this species remained firmly on the radar this week. Hollowell also produced the only rare larid of the week, an adult Caspian Gull on 24th.

Short-eared Owls extended their presence to four localities, kicking off with up to three at Neville’s Lodge (Finedon) between 18th and 24th, one still at Harrington AF between 19th and 23rd, up to two still over setaside east of Stanford Res between 21st and 24th and three at Borough Hill on 21st.

Short-eared Owl, Neville’s Lodge, Finedon, 20th January 2020 (John Moon)
Short-eared Owl, Stanford Res, 21st January 2020 (Chris Hubbard)

Down in the Nene Valley, at Ecton SF, the Siberian Chiffchaff remained throughout the period, being joined there by a second individual on 19th. This new bird was what is often described as a classic ‘Mackintosh-buff’ colour and on close examination it was readily distinguishable from the original bird first discovered on 7th. Twelve Common Chiffchaffs were also present on 20th-21st.

Siberian Chiffchaff, Ecton SF, 19th January 2020 (Alan Coles). The original bird number 1.
Siberian Chiffchaff, Ecton SF, 19th January 2020 (Bob Bullock). The original bird number 1.
Siberian Chiffchaff, Ecton SF, 19th January 2020 (Bob Bullock). Bird number 2 – ‘Mackintosh-buff’ and a different individual to the one in the previous two images.
Siberian Chiffchaff, Ecton SF, 19th January 2020 (Bob Bullock). Bird number 2.

Meanwhile, Stonechats were recorded at five sites, which included DIRFT 3, Hollowell, Pitsford, Stanford and Wicksteed Water Meadows (Kettering), with a maximum of five at Pitsford on 21st. Now, the Siberian version of this species would be a most welcome addition to the county list …

Stonechat, Hollowell Res, 18th January 2020 (Martin Swannell)

Rarity Round-up, 11th to 17th January 2020

In off the Atlantic, Storm Brendan struck in the early part of the week, while the winds were consistently from the south-westerly quarter, reaching thirty miles per hour locally on 14th. Considerable rain topped up and extended local floodwater and while temperatures remained relatively high throughout, a lull ensued in the discovery of new birds during the period.

Perhaps ironically, waterfowl numbers were at a low ebb, with the female Ruddy Shelduck remaining at Hollowell Res on 11th and the drake Red-crested Pochard still present at Summer Leys LNR on 12th. Just along the Nene Valley, two Red-crested Pochards were found at Ditchford GP on 17th. A report of four Greater Scaup at Stanwick GP on 13th remained unconfirmed, while a presumed hybrid female – showing some Tufted Duck characteristics – was at Pitsford Res until at least 14th. The first-winter female, meanwhile, remained at Daventry CP throughout the week.

With no more than two at any one site, Great Egrets were all over the shop, appearing again at eight localities, this week including Clifford Hill GP, Daventry CP, Ditchford GP, Ecton SF, Pitsford, Stanford Res, Stanwick and Summer Leys.

Great Egret, Stanford Res, 12th January 2020 (Chris Hubbard)

The five Cattle Egrets were present at Ditchford throughout the week, roosting on Wilson’s Pits and favouring the small area between the Watersports Pit and the River Nene during the day. Four of them strayed to nearby Stanwick on 15th.

Waders were again in short supply this week with just a Jack Snipe at Ditchford on 12th, while single third-winter Yellow-legged and Caspian Gulls at Daventry CP on 10th were the only scarce larids on offer.

Short-eared Owl, Stanford Res, 12th January 2020 (Chris Hubbard)

Hunting on both sides of the Leicestershire/Northamptonshire county boundary, a Short-eared Owl was found close to Stanford on 12th, another re-emerged at Neville’s Lodge (Finedon) – a proven reliable wintering site for this species in recent years – on 15th and was seen again on 17th, while the Harrington AF bird was seen again on 16th. Others are surely out there, aren’t they! A Merlin was also in the vicinity of Harrington AF on 15th.

Great Grey Shrike, DIRFT 3, 15th January 2020 (Matt Jackson)

Sustained by an apparently inexhaustible supply of small mammals, the DIRFT 3 Great Grey Shrike repeatedly performed well during the period, while the constantly warm area around the processed sewage outflow stream at Ecton SF continued to provide the perfect microclimate for the Siberian Chiffchaff, still present on 14th, along with up to seven wintering Chiffchaffs.

Siberian Chiffchaff, Ecton SF, 12th January 2020 (Angus Molyneux)

Just east of there, at Summer Leys, a Firecrest was reported along the old railway track on 14th.  Stonechats were recorded at four sites, which included Earls Barton GP, Pitsford, Stanford and Wicksteed Water Meadows (Kettering), with a maximum of two at Pitsford on 14th.

Stonechat, Stanford Res, 15th January 2020 (Matt Jackson)


Rarity Round-up, 4th to 10th January 2020

Exceptionally cold air across Greenland this week helped to fuel a strong Atlantic Jetstream, bringing wet, windy and very mild weather to the UK from as far south as the Azores. Not that it made any real difference to the birds we were seeing but it clearly put paid to any hard-weather movements which might have been in the offing at this time of the year. Highlights included the ever-popular, long-staying Great Grey Shrike and a newly discovered Siberian Chiffchaff.

Since the recent disappearance of the adult Whooper Swan which was on the cards to winter at Thrapston GP, this species looks set to revert to its former ‘connection not guaranteed’ status. However, seven dropping into Summer Leys LNR on the afternoon of 4th gave rise to hope they might remain until the following day which, unsurprisingly, they didn’t. On 5th, two flew from Oxfordshire into the upper Cherwell Valley but were not seen subsequently.

Whooper Swans, Summer Leys LNR, 4th January 2020 (Pete Maric)
Whooper Swans, Summer Leys LNR, 4th January 2020 (Pete Maric)

Meanwhile, the female Ruddy Shelduck was back at Hollowell Res on 4th, being seen there again on 10th. The female Greater Scaup continued to be seen at Stanwick GP until 4th and the elusive first-winter female was showing again at Daventry CP on 10th, while the drake Red-crested Pochard remained faithful to Summer Leys LNR’s Main Lake throughout the week.

Great Egrets, now considered part of the winter furniture, were at eight localities, including Ditchford GP, Hollowell, Kislingbury GP, Pitsford, Stanford Res, Stanwick, Summer Leys and Thrapston, with Stanwick holding a maximum of four on 5th. In contrast to last week, however, Cattle Egrets maintained a low profile, with just one at Stanwick on 4th and three at Ditchford GP the following day, on 5th.

Waders remained uncommonly scarce with up to three Jack Snipe remaining at Hollowell throughout the week being the only species of note during the period, while a Yellow-legged Gull at Pitsford on 10th was the only one reported. Away from the wetlands, the Harrington AF Short-eared Owl was again seen on 5th and the Great Grey Shrike remained ever-popular at DIRFT 3 throughout the week.

Great Grey Shrike, DIRFT 3, 4th January 2020 (Martin Swannell)

Not quite matching the latter’s charisma but with its own unique, charming character, was a Siberian Chiffchaff, discovered on 7th in the insect-rich vegetation along the banks of the outflow from Ecton SF into the River Nene. For many years this has been a favoured site for wintering Common Chiffchaffs and it has attracted the odd wintering ‘sibe’ from time to time, including a popular trio in 2013.

Siberian Chiffchaff, Ecton SF, 9th January 2020 (Bob Bullock)
Siberian Chiffchaff, Ecton SF, 9th January 2020 (Bob Bullock)
Common Chiffchaff, Ecton SF, 8th January 2020 (Bob Bullock)

Siberian Chiffchaff is an almost annual visitor to the county, averaging 1.6 records per year over the last two decades, with more recorded on passage during November than in any other month.

Stonechat, Pitsford Res, 4th January 2020 (Ant Hall)

This week’s Stonechats were ensconced in their favoured wintering sites at Hollowell, Pitsford, Stanford, Thrapston and Wicksteed Park (Kettering), with a maximum of four at Pitsford.

Rarity Round-up, 28th December 2019 to 3rd January 2020

The week which straddled two decades and contained the magic ingredient – a bank holiday – saw renewed vigour among local birders keen to kick off their yearlists with the overspill from 2019. The weather was not a key influencer in this respect and remained mild and dry throughout. However, curious things were afoot …

Wildfowl again featured heavily during the period, kicking off with two Dark-bellied Brent Geese paying a brief visit to Hollowell Res on the morning of 31st before quickly departing. A Barnacle Goose bearing what could be a genuine ‘ringer’s ring’ at Clifford Hill GP between 1st and 3rd gave rise to suggestions that it might just be wild as opposed to one from the ever-growing UK feral population.

Barnacle Goose, Clifford Hill GP, 3rd January 2020 (Bob Bullock)

Also on site there, two adult Russian/European/Eurasian White-fronted Geese (capricious nomenclature, so choose your own name) were present from 2nd until mid-morning on 3rd while, just like buses, more Bewick’s Swans came along this week when two flew south-west over Ditchford GP on 28th.

Adult White-fronted Geese, Clifford Hill GP, 3rd January 2020 (Bob Bullock)

The itinerant female Ruddy Shelduck reappeared briefly at Hollowell on 31st before quickly relocating to Foxholes Fisheries (Crick) later in the day, remaining there until 1st, while similarly making it into the New Year was the drake Red-crested Pochard at Summer Leys LNR, on 1st-3rd. Two more drakes were subsequently found at Pitsford Res on 1st, remaining until at least 2nd. The last day of 2019 produced a first-winter female Scaup at Daventry CP ahead of another female found at Stanwick GP on 1st, remaining there until the week’s end.

Female Scaup, Stanwick GP, 2nd January 2020 (Steve Fisher)

Smew numbers dwindled to just one, last week’s drake, still at Pitsford on 30th but inconveniently going AWOL just before the New Year and, adopting the same tack, Hollowell’s two Velvet Scoters did a bunk after 28th.

With no more than two at any single location, Great Egrets were liberally sprinkled throughout the county being noted at Billing GP, Clifford Hill, Daventry CP, Ditchford GP, Earls Barton GP, Foxholes Fisheries, Hollowell, Pitsford, Stanford Res, Stanwick, Summer Leys and Thrapston GP.

Great Egret, Clifford Hill GP, 2nd January 2020 (Doug Goddard)
Great Egret, Pitsford Res, 3rd January 2020 (Tony Stanford)

After their rediscovery at Ditchford GP last week, up to five Cattle Egrets were mobile between the latter site and Stanwick throughout the period, having apparently chosen Wilson’s Pits at Ditchford as a roost site. Will they breed again in 2020?

Cattle Egrets, Ditchford GP, 30th December 2019 (Ady Leybourne)

Far away from the Nene Valley, an eclectic collection of birds included a ‘ringtail’ Hen Harrier at DIRFT 3/Lilbourne Meadows on 30th, up to five Jack Snipes at Hollowell between 28th and 1st and an adult Caspian Gull at Rushton Landfill on 31st while, somewhat vexingly, the Leicestershire gull mecca of Shawell, a mere five kilometres north of Lilbourne Meadows, was enjoying the likes of Glaucous Gull, Iceland Gull and Kumlien’s Gull during the same period. Two sites produced single Short-eared Owls – Harrington AF on 31st and DIRFT 3 the following day, with the latter site continuing to host the highly amenable Great Grey Shrike, enjoying a resurgence in popularity as the New Year broke.

Great Grey Shrike, DIRFT 3, 1st January 2019 (Mike Alibone)

Which brings us to the curious case of the ‘might be’ Penduline Tit, photographed in vegetation around the Ditchford flood pool in which the aforementioned Cattle Egrets had set up temporary home. The blurry photo taken at some distance had all the makings of a monster rare and the suggestion that it was simply an empty drinks can just didn’t hold water.

An investigations team was duly parachuted in the next day, recordings were played and forensics deployed but there was neither sight nor sound of the cameo culprit. While the jury is still out on this one, it’s worth noting that Northamptonshire’s one and only accepted Penduline Tit also occurred at Ditchford, on 22nd October 1983, barely 1,500 metres from the very spot …

Stonechat, Pitsford Res, 2nd January 2020 (Adrian Borley)

Back down to earth, this week’s Stonechats were singles at Billing GP (Whiston Locks), Clifford Hill, DIRFT 3, Hollowell, Pitsford, Stanford, Thrapston and Wicksteed Water Meadows (Kettering), with a maximum of four at Hollowell Res on 30th.

Will 2020 prove to be a record-breaking year on the rarity front? This can only be determined by local birders’ activities in the field, so get out there and pioneer some new sites – you never know what you may find!