Rarity Round-up, 21st-27th September 2019

South-easterlies, warm continental air and sunshine at the very beginning of the period quickly gave way to the more usual Atlantic low pressure systems, a westerly airflow and periods of gusty wind and rain throughout the week. Migrant passerine numbers dwindled, while bird of the week was undoubtedly the juvenile Little Stint, which graced Boddington Reservoir for the last three days of the period.

Wildfowl were thin on the water this week, with the drake Ruddy Shelduck again at Stanford Res on 22nd-23rd and the female being seen at Pitsford Res on 22nd and 27th, while a Common Scoter was reported from Summer Leys LNR on 24th.

Drake Ruddy Shelduck, Stanford Res, 22nd September 2019 (Steve Nichols)

As far as Cattle Egrets were concerned, the Stanwick six were seen only on 21st and four localities – Pitsford Res, Stanford Res, Summer Leys and Thrapston GP – enjoyed the presence of single Great Egrets at one time or another, although Pitsford produced two on 22nd.  The only raptors were two Marsh Harriers – one flying north over Hartwell on 21st and one south at Thrapston GP on 24th.

But the week’s highlight was a juvenile Little Stint at Boddington Res from 25th to 27th. This is only the second in the county this year, which is a far cry from the days when this species was a guaranteed annual passage migrant.

Juvenile Little Stint, Boddington Res, 25th September 2019 (Mike Pollard)

Also at Boddington during this period was a juvenile Ruff, on 26th – another wader exhibiting dwindling numbers in recent years. The only Greenshanks to be found were at Pitsford, where two favoured the dam throughout the week.

Greenshank, Pitsford Res, 22nd September 2019 (Mike Alibone)

On the larid front, Pitsford’s gull roost also produced all of this week’s Mediterranean Gulls, which included a first-winter on 22nd and a second-winter on 23rd, 26th and 27th, while reports of Yellow-legged Gulls fell to just five, which included two at Stanwick GP on 21st, an adult at Pitsford and four at Hollowell Res on 22nd with an adult at the latter site on 23rd and a juvenile at Boddington Res on 26th.

Adult Yellow-legged Gull, Pitsford Res, 22nd September 2019 (Mike Alibone)

And so to passerines and just when you thought there could surely be no more Pied Flycatchers up popped two more, both of which were found at Yardley Chase on 26th, bringing this autumn’s total up to a whopping ten!

Pied Flycatcher, Yardley Chase, 26th September 2019 (Bob Bullock)

Considerably less sought-after but always guaranteed to brighten any birding day, Common Redstarts also kept coming, with singles in the Brampton Valley on 21st and at Little Irchester on 22nd and two at Harrington AF on 25th.

Whinchat, Sywell CP, 24th September 2019 (Alan Francis)

Just two Whinchats included one in the Brampton Valley on 21st and one at Sywell CP on 24th but more migrant Stonechats included one at Hollowell on 22nd-23rd and up to three at Stanford between 22nd and 27th and the week’s only Northern Wheatear was also at Hollowell Res on 21st.

Male Stonechat, Borough Hill, 21st September 2019 (Linda Honeybourne)

The first Rock Pipit of the autumn was found at Daventry CP on 24th. Hopefully there will be more of these to come over the next couple of weeks.

Rarity Round-up, 7th-20th September 2019

If a week is a long time in politics then two weeks is an even longer time – not just double – when it comes to autumn birding. For the major part of the duration, the weather was dry and temperatures were unseasonally high, hitting the mid-twenties. Winds were largely westerly, alternating between the addition of northerly and southerly components, before swinging a decisive south-easterly at the end of the period. While wader numbers tailed off, passerine migrants maintained their prominence at a number of favoured localities.

In terms of species, there was no change to the wildfowl line-up but some local movements saw Hollowell’s long-staying female Ruddy Shelduck up and go on 14th, only to pitch down again a little further north, at Stanford Res, where it remained until at least 18th. Curiously, during this time it was joined there by a male on 16th-17th. Two Garganeys paid a brief visit to Thrapston GP on 14th, another was on the scrape at Summer Leys on 20th, while Thrapston hosted up to three Red-crested Pochards between 10th and 16th and another Red-crested Pochard visited Clifford Hill GP between 15th and 18th.

Numbers of Cattle Egrets at Stanwick GP ranged between one on 9th and six on 19th, while up to two Great Egrets were at both Summer Leys LNR and Pitsford Res throughout and one was seen at Ravensthorpe Res on 17th.

Great Egret, Summer Leys LNR, 13th September 2019 (Alan Coles)
Slavonian Grebe, Clifford Hill GP, 16th September 2019 (Adrian Borley)

On 16th, two Slavonian Grebes were found at Clifford Hill GP in a rare, short-lived period of overcast and drizzly conditions. In keeping with their congener’s one-day appearances so far this autumn they had gone by the following day.
On the raptor front, a Marsh Harrier was in the Brampton Valley on 11th and the number of Ospreys fell to just two – one at Ravensthorpe Res on 7th and the other over Foxholes Fisheries, Crick on 11th, the latter date also producing a male Merlin at Easton-on-the-Hill.

Wader numbers dwindled during the period to a single Ruff at Stanwick between 9th and 11th and Greenshanks at four localities, which included up to three at Hollowell Res between 7th and 14th, two at Pitsford on 7th with one there on 13th, up to two at Boddington Res between 8th and 11th and one at Summer Leys from 9th to 13th.

Greenshank, Summer Leys LNR, 8th September 2019 (Martin Swannell)
Greenshank, Pitsford Res, 16th September 2019 (Alan Francis)

A juvenile Black Tern at Boddington was the only one of its kind during the period and the same site produced a second-winter Mediterranean Gull on 17th, while single first-winters dropped into Daventry CP on 9th and 17th. Daventry also produced a juvenile Caspian Gull on 16th and an adult visited Hollowell on 7th. Yellow-legged Gulls were found at eight sites with maximum counts of ten-plus at Stanwick on 9th and 8 at Thrapston on 14th.

Northamptonshire has enjoyed a great autumn for passerine migrants and again there was no shortage during the review period. It’s been a real ‘Pied Flycatcher autumn’ and they just keep coming, although all of this period’s remained elusive. One was found at Borough Hill on 7th before promptly vanishing and it, or another, (re)appeared there in exactly the same place, three days later, on 10th. Another at Naseby Res, on 12th, also disappeared within minutes of being found.

Common Redstarts maintained a presence with five at Borough Hill on 7th being the maximum site tally. Elsewhere, singles were at Twywell on 8th, Harrington AF on 10th, 13th 18th and 19th (the latter trapped and ringed), two were at Stanford Res on 14th with one there on 17th and two were at Hockerhill  Farm, Wilby – also on 17th.

Whinchats were also still very much in evidence, with up to three at Borough Hill on 7th-8th, up to three in the Brampton Valley between 8th and 17th, two at Neville’s Lodge, Finedon and two at Ditchford GP’s IL&M on 7th, up to two at Harrington AF between 10th and 19th and singles at Thrapston GP on 7th and at Stanford Res on 14th – the latter trapped and ringed.

Whinchat, Stanford Res, 14th September 2019 (Chris Hubbard)
Whinchat, Brampton Valley, 15th September 2019 (Alan Coles)

The first migrant Stonechats of the autumn also arrived during the period. Singles were at Harrington AF on 10th and 19th, three were at Stanford Res on 14th with one remaining the next day, two were in the Brampton Valley below Hanging Houghton on 17th and two at Summer Leys the following day and singles were found at Milton Malsor on 17th, Wicksteed Water Meadows, Kettering on 17th and 20th and at both Thrapston GP and Borough Hill on 19th.

Stonechat, Stanford Res, 15th September 2019 (Chris Hubbard)
Stonechat, Brampton Valley, 20th September 2019 (Martin Swannell)

Northern Wheatears continued to trickle through, with singles at Hollowell Res on 7th and 14th, Harrington AF on 10th and 13th, Orlingbury on 13th, Clifford Hill GP on 15th-16th, in the Brampton Valley on 17th and at Borough Hill on 19th.

Northern Wheatear, Clifford Hill GP, 16th September 2019 (Doug Goddard)

Rarely identified in autumn, for some reason, a White Wagtail was found at Boddington Res on 7th and on the same date, single Tree Pipits flew over Borough Hill and Croughton Quarry.

Rarity Round-up, 31st August to 6th September 2019

Temperatures fell as the prevailing Atlantic airflow re-established itself, delivering brisk, breezy and mainly dry conditions on the back of variable northerly to south-westerly winds. Local birding survived on the remnants of last week’s migrant rush, the usual long-stayers were still in place, with the popular well-watched sites continuing to produce small numbers of new birds.

At Hollowell Res the female Ruddy Shelduck remained until at least 3rd, while single Garganeys at Pitsford Res on 31st and at Summer Leys LNR on 3rd were both new in.  Unusually scarce so far this autumn, a single drake Red-crested Pochard at Clifford Hill GP on 5th was the only one of its kind in the county this week.

Garganey, Summer Leys LNR, 3rd September 2019 (Alan Coles)

For those still following the Quail trail, it may not yet have gone completely cold, as one was flushed from setaside on the northern edge of Orlingbury on 1st. There are October records from at least one previous year …

Up to six Cattle Egrets remained at Stanwick GP throughout and Great Egrets became marginally more widespread with, in addition to the two at Summer Leys LNR and one at Pitsford Res, on and off, new birds at Ditchford GP’s Irthlingborough Lakes and Meadows LNR on 3rd and at Wicksteed Water Meadows, Kettering on the same date.

And so to the mysterious case of the Night Heron, which was reported from two sites in close proximity at Ditchford GP. Specific grid locations emerged from the ether on 31st and whys and wherefores notwithstanding, locals looked there but the willows were bare – if they ever held fruit in the first place.

Nothing so mysterious about a Black-necked Grebe at Pitsford Res on 1st – remarkably, again, only a one-day bird, or so it would seem.

On the raptor front, a Marsh Harrier flew east over Stanwick’s Visitor Centre on 5th but the number of Ospreys dwindled again to singles at Hollowell, Pitsford and Thrapston on 31st, the latter site hanging on to its bird until the next day.

A poor showing for waders this week saw just one adult Black-tailed Godwit at Summer Leys on 3rd-4th and up to three Greenshanks at Hollowell between 31st and 3rd, plus one at Summer Leys all week and two at Boddington Res on 6th.

Adult Black-tailed Godwit, Summer Leys LNR, 3rd September 2019 (Alan Coles)
Greenshank, Summer Leys LNR, 3rd September 2019 (Alan Coles)

For the second week running, a juvenile Little Tern made its way to the county, appearing at Stanwick GP early in the morning of 2nd. Aside from that, a juvenile Arctic Tern at Pitsford on the same date was noteworthy. Pitsford also attracted a juvenile Little Gull for the best part of the week, between 31st and 5th. Again, just one Mediterranean Gull was found – this time a first-winter – at Boddington on 2nd, while a juvenile Caspian Gull appeared at Stanwick on 1st.

First-winter Mediterranean Gull, Boddington Res, 2nd September 2019 (Mike Pollard)

Single adult Yellow-legged Gulls were at Ravensthorpe on 31st, Stanwick on 1st, Hollowell on 1st and 3rd and at Pitsford on 5th but seventeen were counted at Stanwick on 6th.

Adult Yellow-legged Gull, Stanwick GP, 6th September 2019 (Steve Fisher)

The flood of passerines last week had abated somewhat by the end of the period but Common Redstarts continued to appear in higher than average numbers. Stanford held two on 31st and one was trapped there on 3rd. The last day of August also produced singles near Lamport and at Pitsford and two at Twywell, while the following day saw singles at Harrington AF and Hollowell and three at Fawsley Park. On 3rd, there were four near Walgrave and two at Blueberry Farm, Maidwell – the latter having dropped to one by 5th, on which date there were up to two at Harrington and singles at Wollaston and Fleetland Farm (Duston), Northampton.

Adult female Common Redstart, Stanford Res, 3rd September 2019 (Dawn Sheffield)

Numbers of Whinchats were also still much in evidence, with five at Wollaston on 31st and 5th, up to three were in the Brampton Valley at Blueberry Farm between 1st and 5th, three were at Neville’s Lodge, Finedon on 2nd, singles were at Harrington and Pitsford on 5th and three were at Fleetland Farm on the same date. Northern Wheatears were, however, less abundant with only singles at Fawsley Park on 1st, Harrington on 1st-3rd, Blueberry Farm on 2nd and near East Haddon on 5th.

Pied Flycatcher, Barnwell CP, 1st September 2019 (John Hunt)

Another Pied Flycatcher discovered at Barnwell CP on 31st remained until the following day, continuing this species’ record run so far this autumn. Back at Blueberry Farm, a Corn Bunting on 3rd was the first record in the county since the last winter period.

A gull which doesn’t quite fit the bill

A closer look at the Ravensthorpe ‘Caspian’ Gull

Generally regarded as a Caspian Gull, this second-calendar year (first-summer) bird has been visiting Ravensthorpe Reservoir since early August. From the initial images obtained by Gary Pullan, it looked marvelously ‘snouty’ and long-legged – two features widely associated with Caspian Gull.

Second calendar year gull, Ravensthorpe Res, 16th August 2019 (Gary Pullan)

There were, however, some characteristics which simply did not ring right for Caspian Gull, leading Gary and I to debate its identity, which swung from Caspian to Yellow-legged, though Caspian x Yellow-legged hybrid and then back to Caspian. John Moon chipped in with a better image, which did not really change anything at the time.

Second calendar year gull, Ravensthorpe Res, 19th August 2019 (John Moon)

On 31st August, I managed to get some digiscoped shots (below) of which some, after scrutiny, were perhaps more suggestive of Yellow-legged Gull – not least because of the bill structure.

Summary of features based primarily on images taken on 31st August.

  • Large and lanky and legs long and good for Caspian
  • Shortish (closed) wings but renewed primaries probably still growing
  • Mantle shade of grey too light for Yellow-leggedGul but OK for Caspian (but see comments)
  • Bill long but heavy, with large gonys – looks in some images to be fine for Yellow-legged Gull but too chunky for Caspian but in others ok(ish) for Caspian
  • Underwing coverts quite dark – darker than I would expect for Caspian but Malling Olsen states some Caspians can have quite dark underwings (and see comments below)
  • Head shape, long forehead and eye position ok for Caspian and looks ‘snouty’

I forwarded a set of images to Carl Baggott – the Leicestershire Recorder, ‘King of Shawell’ and a man with a true passion for gulls and with extensive experience of Caspian and Yellow-legged Gulls in eastern Europe and Yellow-legged in Portugal.

Carl kindly commented as follows:

This is quite a difficult bird, but I don’t get a Caspian Gull feel from the images. It seems closer to YLG and I am not too concerned about the lightness of the grey feathers as this is quite variable at that age. The tertials favour YLG also, as does the large head and bill. The snouty description of Caspian Gull head is overstressed and doesn’t really help with most gulls. As you say some Caspian Gulls can have dark underwings and I have photographed birds in Germany with similar underwings. Most 2CY Caspian Gulls have pale inner primaries or a venetian blind effect across the inner primaries.

I have seen birds like this at Shawell and left them unidentified. It can be very difficult with ones like this as you don’t know their origin. I have seen Yellow-legged Gulls in Portugal that are easily confused with Caspian Gulls and even American Herring Gulls.

On the question of the possibility of a hybrid:

It could well be [a hybrid], but difficult to say for certain. There is nothing to really hang your hat on. A colour-ring is always useful as you know so at least you know where it’s from. Hybrids are easier as adults or first-winters usually as you can look at coverts (Caspian Gulls especially) on the young birds and primaries on adults. Then it comes down to matter of opinion unless you know the species of the parents. Hybrid is always the go to, but there is a great deal of variation in pure birds.

The above not only highlights the difficulty of identifying ‘odd’ gulls in the field but also the problems with trying to identify them from images taken from different angles and in different poses – for example, see the apparent change in head shape and bill thickness in the above images.

For a set of images of similarly-aged Yellow-legged and Caspian Gulls in The Netherlands  see here.

Comments welcomed!