Category: Storks, Herons and allies

It may come as no surprise to many but Northamptonshire now joins Cheshire, Dorset, Devon, Essex, Hampshire and Somerset as counties which have played host to breeding Cattle Egrets in the UK.

Discovered by Steve Fisher on 8th June, an adult apparently incubating eggs, within a mixed Little Egret and Grey Heron colony in the Nene Valley, gave rise to optimism that we were only a few weeks away from seeing successful local breeding.

Formerly a very rare vagrant, Cattle Egret has become a more regular sight in the UK in recent years, following several large influxes. The first in 2007 saw over 200 arriving throughout Britain and Ireland and resulted in successful breeding in the Somerset Levels in 2008. Another influx in 2016 brought even larger numbers, with further successful breeding in Cheshire in 2017, during which two more colonies were discovered, giving rise to a total of 10 pairs.

In Northamptonshire, Cattle Egret was first recorded in 2006, when one was present at Summer Leys LNR from 11th to 13th August. Others soon followed and individuals of this species were recorded in five of the twelve years between 2006 and 2017, with the first ‘multiple’ (two together) occurring only as recently as 2018. Up to 4 made a protracted stay at Stanwick GP between mid-October and mid-December 2018, after which singles appeared there and at nearby Ditchford GP in March this year, with 3 adults at Stanwick regularly from late May.

 
Breeding then followed and after hatching successfully, young were observed in the nest for the first time on 1st July. A week later they were looking significantly bigger and today (17th July) one was standing on the nest, stretching, walking and preening and fledging appears likely within the very near future. Because of the vegetation cover, it is not possible to be certain if there are 2 or 3 young at this point. One adult was in attendance and two more adults – making up the original ‘Stanwick three’ – flew in to join it after being observed with cattle at Stanwick some ten minutes earlier.

 
Interesting behaviour followed as two of the birds attended to ‘housekeeping’, one of the arrivals passing a stick to the attendant, which then proceeded to add it to the nest platform before breaking off another twig from a nearby bush and repeating the behaviour. According to BWP, both sexes engage in nest-building, the female taking sticks passed to her by the male, one at a time, before putting them in place, with material continually added to the structure during incubation and long after hatching.

Of further interest is that all three adults appear to be involved in the family business, i.e. the breeding pair has a helper, or even a ‘nanny’, if you will. Again, BWP states that temporary trios of two females and one male are not infrequent at the start of the breeding season but these three appear to have stayed together throughout.

Northamptonshire is not alone in producing a breeding pair in 2019. Others have bred in Hampshire and Essex, away from the initial location in the Somerset Levels.

The information on breeding has now been released on the basis that anyone who wants to see a Cattle Egret will have done so by now. Surrounded by water, the site is largely inaccessible and will therefore not suffer from disturbance, successful hatching precludes the possibility of potential egg-theft and the young will shortly leave the nest. It is also unlikely the site will be used again … but who knows?!

Rapid population growth and range expansion is characteristic of Cattle Egret, which is now probably the most widespread species of bird on the planet, having colonised Europe, the Middle East, and North America from Africa, and Australia from Asia.

With special consent from Natural England, Assistant Warden Mischa Cross explains how specialist equipment was used with careful planning to accurately survey nesting Grey Herons at Pitsford.

In early May 2017, the heronry at Pitsford Reservoir Nature Reserve was surveyed using a drone to see if a more accurate count of nests could be established with this method, rather than counting from on the ground. The trial proved very successful with 14 nests counted from the drone footage, compared with 10 nests counted from the ground.

The survey was timed so that the eggs had hatched. This meant adult birds would not be sitting on the nests incubating eggs, as they may be inclined to leave the nest, risking damage or chilling of the eggs. One flight was sufficient to get the required footage and it lasted no longer than 10 minutes. The drone used was a DJI Phantom Vision 2+ v.3, which can fly up to a maximum height of 300ft. For this survey the height was set at 200ft so better quality images could be captured in an attempt to see if egrets were also using the area. It was hoped to get video footage but unfortunately this was unavailable on the day of the survey. The drone was piloted by fully qualified, CAA approved and insured pilot, Josh Hellon. The pilot was always in full manual control of the UAV/drone and it has a failsafe that returns it to the take-off point if there are any problems.

Observations were made from the ground while the drone was in the air to see how the birds in the area reacted to the presence of the drone. No obvious signs of disturbance were witnessed. As the eggs were hatched, the adult birds are likely to have been away from the nest collecting food.

The First in Spring

The words ‘Glossy Ibis’ and ‘Northamptonshire’, when occurring together in the same sentence, are now predictably accompanied by adjectives such as ‘short-staying’, ‘fleeting’, or ‘transient’ to describe this species’ visits to the county. The first one to occur in spring followed the now well established occurrence pattern seemingly mandatory for Glossy Ibises in Northants. This individual managed little more than two hours at Summer Leys today, having been discovered at 11.30, before flying off west at 13.35. Images below from Alan Coles.

                                                                                                                              

This is only the fifth county record, following singles at Ravensthorpe Reservoir on 20th September 2002, Pitsford Reservoir on 17th September 2010, Stanwick GP on 12th October 2013 and Daventry CP on 28th September 2016.

Northamptonshire’s 6th Cattle Egret was found by Neil Underwood this morning, close to the site of last month’s White-fronted Goose grazing area alongside the River Nene, at Dunkleys, between Whiston and Earls Barton. Around midday it moved a few hundred metres to the south to a weedy field between Dunkleys and the newly-formed earth bank running alongside the new quarry conveyor belt.

In a winter notable for its Cattle Egret invasion it would have been surprising (and disappointing!) if Northants had not featured. Currently there are well over 100 individuals at large in the UK, most of which are in south-west England, although some have reached as far north as Lancashire.

A few digiscoped shots below.                                                                                                                                           Lack of dark tip to bill (when not soil-covered) ages it as an adult. There have been 5 previous  records, 4 of which have been in the same short stretch of the Nene Valley as this one. Previous accepted records are:

2006   Earls Barton GP, 11th-13th August                                                                                                                 2008   Fotheringhay, 23rd February; Earls Barton GP, 30th-31st July                                               2009   Earls Barton GP, 27th-28th May                                                                                                            2012   Earls Barton GP, 1st-6th May

Wow! A Northamptonshire rarity, an adult Glossy Ibis, made landfall at Daventry Country Park today. Found by Mark Spirito on the southern shoreline, just after 09.20, the news was put out immediately and a handful of birders, quick off the mark, made it to Daventry just in time to see it before it took to the air at 10.43 and headed off south. I managed a few seconds of long distance video before it took to the air …

This is only the fourth county record, following singles at Ravensthorpe Reservoir on 20th September 2002, Pitsford Reservoir on 17th September 2010 and Stanwick GP on 12th October 2013. At least two others have been reported but the records have not been submitted.

Ageing and Local Status

Summer Leys, early morning on 7th May. A steady trickle of interesting waders throughout the previous day had encouraged a handful of birders to occupy Pioneer Hide in readiness for ‘the big one.’ As it happened there were four ‘big ones’, which arrived from the south at 07.45, sweeping in a wide arc over the main lake before landing on the scrape. Spoonbills!

They stayed for approximately forty-five minutes – just long enough for some decent photos and video and for a few locals to catch up with them before they headed off to the north-west. As they flew in it was obvious that three of them were immatures, each showing variable amounts of black tips to the primaries and, on at least two of them, the secondaries also, as Matt Hazleton’s image below nicely illustrates.

Ageing Spoonbills to year is not as straightforward as it might at first seem (see Alexander Hellquist’s analysis). Bill colour, leg colour and the extent of black in the wing are all variable and relate to hatching time, wear and the condition of the bird in general. However, looking at the three immatures, it would appear we have one 2nd calendar year and two 3rd calendar year birds – as well as an adult, of course.

The 2nd calendar year individual shows all the features of a bird of that age, i.e. extensively dark fleshy-yellowish bill with darker grey basal part and yellowish base to lower mandible, plain pale yellowish lores, dark brown eye, lack of short plumes at rear of crown and grey legs. The 3rd calendar year birds show extensively darker bill with paler yellowish-flesh toward tip, blackish base to lower mandible, obvious black loral line, redder eyes, beginnings of short plumes (short tuft) at rear of crown and dark grey-black legs. What is puzzling, however, is the more extensive black tips to primaries and secondaries of the 3^rd calendar year birds (both are also different) than the 2^nd calendar year. In theory, this should be reversed!

Spoonbills are still rare visitors to Northants. The first county record was as recently as 1965 and there have been thirty-two records in total, the vast majority of which relate to single birds.

A flock of four is not unprecedented, however, with this number having occurred in April 1983 and eight in September 1984 – both records from Pitsford Reservoir. May is the month to find one and there are still three weeks left …

The Ditchford Night Heron

Ditchford’s recently discovered adult Night Heron – Northamptonshire’s tenth – is continuing to draw the local crowds with around 30 birders enjoying the best views yet of this bird last night. It’s still not the easiest of Night Herons to see as Jim Dunkley’s image below demonstrates.

Last night it was very vocal, calling for some 10 minutes from willows by the Bailey bridge before flying off toward Wilson’s Pit at around 22.00. An excellent sound recording made by Adrian Borley is here. For anyone still to make the trip there, it’s around 15 minutes’ walk along the Nene Way footpath from Ditchford Lane. Park near the entrance to Broadholme Sewage Works SP930684 (do not obstruct the entrance as it is in constant use by HGVs), walk east for c.1200 m to the Bailey bridge SP944686 and view from this area. It normally appears any time between 20.15 and 21.45.

Receiving far less attention than the nearby Ring-necked Duck, this ‘black-fronted’ Grey Heron proved to be quite a striking bird. At first sight it may be easy to assume it is oiled but closer examination reveals a rather uniform density of dark feather symmetry – not the patchy, uneven distribution of staining associated with a liquid, and this suggests it is natural pigmentation rather than the result of an oily encounter.

Grey Herons with aberrant plumage occur from time to time. Structurally, the Wicksteed individual is a Grey Heron and is not likely to be a hybrid, unlike this bird, which it closely resembles in plumage but not structure. Interesting bird and thanks to Simon Hales for his image.

Clues to the origin of our Great White Egrets

Tempting as it is to believe that our Great White Egrets originate from The Netherlands (and some may well do so) it appears that the colour-ringed individual currently at Pitsford Reservoir has channel-hopped from France.

The combination of ring colours allows it to be identified as one ringed as a nestling at Lac de Grand-Lieu (Loire Atlantique), in western France, on 14th May 2014. In addition, it also bears a numbered metal ring inscribed CA76915 on its right tibia.

Before it arrived at Pitsford it was also seen at Amwell Nature Reserve, Hertfordshire, on 6th August. This adds to the growing number of British records of other known colour-ringed individuals which originate in France. The returning Blashford Lakes (Hampshire) bird – also ringed at Lac de Grand-Lieu and now enjoying its 12th great UK winter – is a prime example and strongly suggests that wintering birds are site-faithful.

Thanks to Adrian Borley for finding the bird and supplying the images and many thanks to Loïc Marion, the ringer of this bird at Lac de Grand-Lieu, for providing the above information. The Lac is the most important site in France for this species, with a recent breeding population estimate of 144-165 pairs (2008-2010).

Great White Egrets in Northamptonshire

I remember when they were rare. A long drive to Scaling Dam Reservoir in North Yorkshire with Chris Ingram in June 1974 ended in a car crash, the journey to site completed by bus, followed by a long train journey home, sadly returning empty-handed. At the time, it was only the 11th or 12th for Britain and it was to be a few more years before I eventually caught up with one.

News of Northamptonshire’s first (and, by now, Britain’s 57th) broke late in the afternoon on Sunday, 5th July 1992. A quick dash to Stanford Reservoir and there it was, feeding quietly in the shallows of Blower’s Lodge Bay – a shimmering vision in white on a sunny summer’s evening.

Further records followed – the next briefly at Thrapston GP on 18th February 1994, before being seen at Earls Barton GP two days later, and then the first long-stayer, which was found at Billing Aquadrome on 27th November 1997. It remained in the Nene Valley until March 1998, visiting Ecton SF, and gravel pits at Billing, Earls Barton, Ditchford, Stanwick and Thrapston during its four-month stay. As well as setting the trend for the now emerging pattern of records of overwintering in the county, this individual elicited considerable interest because of its apparently wholly black legs, including tibia, and bright orangey bill – characteristics which, at the time, were believed to be strongly indicative of the Nearctic race egretta. This race is not officially on the British list.

We now know better as many of our visiting Great Whites appear to have blackish tibia in winter as standard, as well as brightly-coloured bills, while egretta is said to average 10% smaller, although determining the size of a lone individual in the field is likely to be problematic. According to the British Birds Rarities Committee differences in bare-part colours between European nominate alba and egretta do exist but they may be only average differences and efforts to establish practical identification guidelines are underway; biometrics are diagnostic, however.

The next occurrence in Northants was also interesting but for a different reason: it involved the first flock to occur locally. Three together in flight over Stortons GP on 7th October 2002 was an amazing sight for Chris Coe on his local lunchtime patch and three remains the largest number seen together anywhere in the county to date.

The graphs below provide an overview of occurrence since the species first appeared in Northants in 1992.

In both histograms only the first date of arrival is used within the statistics, i.e. two birds arriving together at Pitsford Reservoir in October and staying until February the following year constitutes one record and appears just once, in the column for October, for that one year only.

There is a clear trend emerging, with the highest number of birds arriving to winter during the last quarter with a distinct peak in October, clearly the best month in which to find your own.

Aside from the first breeding in Somerset in 2012, the records for Northants mirror those nationally and reflect this species’ recent increase on the near continent as this species continues to expand its range westward.

It seems likely that Great White Egrets will follow in the footsteps of Little Egret – at least to some degree – and they are therefore likely to become an increasingly regular sight at our local bodies of water during the winter months.

I would like to thank Clive Bowley, Bob Bullock, Alan Coles, Simon Hales, Douglas McFarlane, Keith Stone and Simon Wantling for supplying the images used to illustrate this post.