26 Years of the BBS at Amberswood Common

Amberswood Common lies approximately 1.75 miles south-east of Wigan town centre and is surrounded on all sides by the communities of Hindley, Ince, Spring View and Platt Bridge. The site includes a good-sized area on its western side once known as Ince Moss and is spread across four 1km squares (SD5904, SD6003, SD6004 & SD6104). It lies about one mile from the eastern boundary of the Wigan Flashes LNR to the west, separated by Spring View and the West Coast Mainline.

Mosslands once stretched over much of the Borough of Wigan; in the 17th Century, they covered the area now known as Amberswood Common and stretched south-east through the Wigan Flashes along the Leeds-Liverpool canal to Leigh. These mosses were drained during the industrial period, and the landform changed when the land subsided and much of the area was tipped over.

Large parts of Wigan were shaped by mining as early as the mid-1800s. After the coal industry began to close down in the 1960s some of the former collieries, instantly recognisable from their mounds or spoil heaps, began to return to nature, but some – including Amberswood – were subjected to opencast mining in the, leaving distinctive visual eye-sores on the landscape.  Much of this dereliction has subsequently been treated by Lancashire County Council, Greater Manchester Joint Reclamation Team and Wigan Council, with varying degrees of success. 

Many of the wildlife sites in Wigan have developed as a result of this past industrial activity. Subsidence from former coal mines has created many areas of open water, known locally as flashes, which support extensive reedbeds and the specialist wildlife which lives there. The majority of the 160-hectare Amberswood Common site was reclaimed soon after the opencast operation, which ceased in 1988.

The result of this reclamation is that Amberswood Common is now an extensive and diverse habitat with a high water table, consisting of a lake and a series of smaller ponds and lowland raised bog, linked by ditches and streams, and interspersed with species-rich neutral and acid grassland dominated by Reed Canary Grass Phalaris arundinacea. There are also several plantations of deciduous, coniferous and mixed woodland, made up of Scots pine, poplar, alder, cherry, silver birch, oak, rowan and white willow. Many of the trees were densely planted, so ground flora is limited, although a moderate understory is now developing. A number of these habitats are Greater Manchester Biodiversity Habitats. 

Amberswood Common provides valuable habitat for a range of wildlife, including the elusive Water Vole and frogs, toads and newts, which take advantage of the ditch network.  The site is host to a huge variety of birds (163 species recorded to date since data collection began in 1992), dragonflies (I have recorded 11 species over all my visits to the site), damselflies (5 species), demoiselles (1 species), butterflies (17 species), moths and other invertebrates. Roe Deer use the woodlands, as do Willow Tits; one of the fastest declining bird species in Britain, and a Red List species of conservation concern, its abundance has fallen by 92% between 1967 and 2016 nationwide (Woodward et al 2018), but it breeds in good numbers on the Common.

My 1km survey square takes in almost half of the overall area of Amberswood Common, as defined by the boundaries of the Grade B Site of Biological Importance (SBI) status it was granted in 2004. 

When I was allocated the BBS square SD6004, part of which lies on Amberswood Common, I undertook a habitat survey and worked out two transects. This was a real challenge due to the number of physical obstructions on the site - plantations with no paths, brooks, ponds, buildings, private land - and my unfamiliarity with the area. The ideal route for Section 6 should’ve taken me across a large private garden but there was no access so I’ve always had to stand by the road at the (southern) end of the section and look back along the land where the route would have been (red dotted line on the map). 

The route of my two transects has changed twice since 1995 because of changes of access to two of the ten sections.

In the early-2000s the industrial estate, which I used to walk alongside when undertaking section 4, was extended eastwards into the triangle formed by the narrow pond and the railway embankment, forcing me to alter my route around it (amber line).

Then, in October 2003, the landfill site, which was only active on a small scale anyway and only at the eastern end, closed, was capped, grassed-over and access denied (I’d previously climbed through gaps in the fencing at each end of the site – shh, don’t tell anyone – but these were closed when the site was capped). The only way I was able to continue to survey this section was to stand at the southern end of the site and look back along the route, watching and listening for any signs of birdlife (dotted blue line).

Judith recounts, that in the three years following the start of the reclamation, the then still active landfill site attracted many thousands of gulls and good numbers of corvids, as well as large numbers of Lapwing, Golden Plover as well as a few Pink-footed Geese, all of which were attracted to the bare, freshly-turned earth. 

Tree planting began on the Common in January 1989, mainly on the west side of the lake. This water attracted a whole spectrum of waders; it seemed the lake’s position and aspect were attractive to passage migrants, and the shallow muddy fringes of the lake, uncolonised by vegetation, were ideal habitat for these species. 

By autumn 1991, the plantations had reached sapling height and the habitat was ideal for wintering raptors. Short-eared Owls and Kestrels duly appeared to take advantage of the small mammal population, and the growing trees also attracted a flock of fieldfares.

Little Ringed Plover, Lapwing, Snipe and Redshank were all thought to breed on the site, as did the locally-rare Yellow Wagtail.

By the time Mum and I were undertaking my first BBS visit on 8th May 1995 the site was quite different and much less ‘wild’. The plantations were still at the sapling stage but a network of paths was well established and the ground elsewhere was well-covered with grasslands and some
scrub.

Lapwing

When I started recording on the Common, Lapwings were only present in low numbers and were mostly encountered on the landfill site which was still active, albeit on a small scale. The overall drying-out of the ground since reclamation has made the site unattractive to Lapwings, and since the landfill was capped and grassed over in 2003 numbers have dropped dramatically. They’ve now disappeared completely from the survey.

Skylark

Another species of high conservation concern, Skylark was present in good numbers and were recorded from six of the ten sections of the survey in 1995, with a maximum count of thirteen on the early visit and ten on the late visit.

My rose-tinted memory is of Skylarks flying up from everywhere, although that’s not actually the case. Numbers have fallen steadily, and more dramatically than the BBS index for the same period. Almost all records since 1999 have come from the (former) landfill site and I haven’t heard their beautiful song anywhere on the survey since 2017.

Starling, Cuckoo, Redshank and Grey Partridge

Other species of national concern, recorded in the first few years of the survey, have sadly disappeared too. Starling, Cuckoo, Redshank and Grey Partridge were all recorded in 1995, but after that, all became only occasional names on my recording sheets.

Bizarrely, after not recording any of the four species for ten years, I found three of the four species in 2014. Sheer coincidence must be the only reason as none have been encountered since.

The loss of these species from my survey square is very sad and reflects their demise across the UK in recent years.

Wren, Robin and Blackbird

The more common species living on Amberswood Common are, thankfully, faring much better.

Numbers of the three most numerous woodland-dwelling species, Wren, Robin and Blackbird, have risen steadily as the plantations of deciduous and mixed woodlands have grown.

Wren has always been the most abundant of the three species on the survey, and their numbers have increased steadily through the years; the average number recorded per year doubled between 1995 and 2020.  

Robin was the least numerous of the three in 1995 but overtook Blackbird in 2005, increasing three-fold over the years, with Blackbirds showing the smallest increase.

These trajectories seem linked to the species’ preferred nesting habitat. The plantation trees grow much more slowly than the shrubs and herbs, so new potential nest locations for Blackbirds - forks in branches - are slower to appear than nesting spaces in the shrub layer which are used by Wrens and Robins.  I would imagine the numbers of Wrens and Robins will continue to increase until this growth outpaces the number of new available nesting sites in the understory, then numbers will plateau.

Woodland Warblers

Before downloading my data from the BBS pages on BTO's website for this article, my gut feeling was that the populations of the three commonest woodland-dwelling summer migrants, Willow Warbler, Chiffchaff and Blackcap, had all undergone noticeable changes. I thought that Willow Warblers are now less numerous than they were in 1995, while both Chiffchaff and Blackcap had become more numerous.

I converted the data for these three species into a graph and was pleased to see that my ‘hunch’ proved correct.

The graph clearly shows that Willow Warbler numbers have fallen steadily, and almost three-fold. In contrast to Robins, Wrens and Blackbirds which have all benefitted from the woodland ageing, the opposite is true of Willow Warblers, which prefer young woodland or plantations.

In 1995, much of the plantation habitat at Amberswood was only six to seven years old, so it was ideal for ‘Wilbers’ - but not for Chiffchaffs, which prefer larger, more mature trees, and Blackcaps, which need a reasonable amount of understorey. The ageing woodlands have become better habitats for the latter two species and poorer for the first, hence the shifts in average maximum counts.

Blackcap numbers on the survey, which have increased at least four-fold, haven’t quite overtaken those of Willow Warbler, but I expect that will happen in a year or two. Chiffchaffs, which have increased an amazing 13-fold since I started the survey, overtook ‘Wilbers’ in numbers in 2016, and I expect the difference between these similar-looking species to continue to increase in the years to come.

Reed and marsh dwelling Warblers 

As the vegetation around the site has grown since 1995, some of the wet areas have, as you’d expect, begun to dry out and are in the early stages of scrub (despite the high water-table) and Phragmites reedbed succession (because of the high water table). It was clear to me that numbers of Sedge Warblers had fallen over the years, from an already low starting point, and the species was soon almost absent from the survey. Individual birds were recorded 2010-2012, but none have been recorded since. There are suitable habitats in other parts of Amberswood Common, outside of the survey area to the west, but the distinctive song of the Sedge Warbler appears to be lost from SD6004.

In contrast, the numbers of Reed Warblers are of international importance in the Wigan area as it provides many wetland flashes and riparian habitats. Numbers in my BBS count have increased five-fold since 1995. This has corresponded with a substantial increase in the amount of Phragmites australis (Common Reed) over the years across the survey square, particularly around the northern and eastern sides of Amberswood Lake (Judith estimated its depth at around 20 feet deep in places now). The pond marked on the map has seen a large increase too, as have other boggy areas and even alongside footpaths, where there is no visible water. This seemingly unstoppable march has provided more and more suitable nest sites for Reed Warblers, and I expect this trend to continue.

I’ve recorded Reed Warblers’ instantly-recognisable “chugging” song from eight of the ten sections of the survey, including section 5 (not officially part of Amberswood Common) where a small reedbed is surrounded on all sides by a noisy food processing plant, a brook, housing and a tall railway embankment (where I also recorded a “first-ever” a few years ago... keep reading).

Reed Bunting

My gut-feeling about populations of the three reed- and marsh-dwelling species at Amberswood was correct for two of them, but not the third. The first, the Reed Bunting, doesn't appear to be doing so well in SD6004. Whilst numbers have changed little in the past 26 years, there has been a small and steady decline in the number of this marsh-dwelling species. This is in contrast with the national trend, and it’s possible that changes to the habitat at Amberswood are imperceptibly making the area less suitable for Reed Bunting. Having said that, reedbeds are an important habitat for them so there may be other reasons for the small fall in number. As with Sedge Warbler, there are still suitable habitats in other parts of Amberswood Common, outside of the survey area to the west, so I hope they’re both doing well there. I happen to like the simple song of this handsome bird so fingers crossed their population in SD6004 doesn’t decline any further.

Great Tit and Blue Tit 

I have recorded five species of tits on the survey, two of which are far more abundant than the others.

Long-tailed tit has appeared on my survey sheets in most years, with a maximum yearly count of eight. I’ve only recorded seven Coal Tits since 1995, with a maximum yearly count of just two. Since my route doesn’t pass through any of the coniferous woodlands on Amberswood this low occurrence comes as no surprise.

However, two common tit species are doing well in SD6004: Great Tit and Blue Tit. Numbers of Great Tit have more than doubled since 1995, with definite peaks in abundance in 2010 and 2019 (the dramatic fall in 2020 was probably down to the fact that the early visit was cancelled because of COVID-19 restrictions). Doubtless the maturing of the woodlands has generated more suitable nest locations. Blue Tit numbers have increased over the years too, probably for the same reason that their larger cousins have increased. It’s also possible that this rise in the abundance of both species is partly due to the fact that Brits feed “their” garden birds like no other nationality, with the subsequent boost in breeding success resulting in excess birds ‘spilling’ onto Amberswood Common from the large urban areas that surround it.

Willow Tit

One of the UK's most rapidly-declining birds, the Willow Tit, enjoys good fortune across Amberswood Common and Wigan Flashes. The endemic Poecile montanus kleinschmidti is disappearing from its former haunts at an alarming rate, but is increasing in my survey square.

Since 2012, Wayne Parry and Richard Broughton have been undertaking a comprehensive survey of every aspect of Willow Tit life at this combined study site. This has involved ringing 131 adults and 469 nestlings, mapping the territories of all breeding pairs, taking measurements of nest-hole height, diameter and position, and recording brood size, clutch size, brood success rate, and causes of nest loss. Their project was even featured on BBC Springwatch in 2021.

Their paper, published in 2019, states that “Based on the national estimate of 2,750 breeding pairs in 2016 (Woodward et al. 2020), the 35–37 pairs on our single study site represent 1.3% of the British and global population of this endemic subspecies. To put this figure into some context, under the Ramsar Convention on Wetlands a site is considered internationally important if it regularly supports 1% of the population of a waterbird species or subspecies (Grobicki et al. 2016). Willow Tits are not waterbirds, although the British subspecies is often associated with damp woodland and scrub integrated with wetlands, but if similar criteria to the Ramsar Convention were applied, hypothetically, then our site could be considered as internationally important for this taxon.” (Broughton, Parry & Maziarz 2019).

I was recording Willow Tits at the Wigan Flashes two decades ago but it took until 2007 for one to appear on my BBS recording sheets at Amberswood, and then there was a five-year wait for the next. Encounters have been more frequent since 2012 but are still uncommon. Parry & Broughton mapped 18 territories across Amberswood in 2018; it seems I have been unlucky not to have recorded more! I’m sure their sedentary nature contributes to the paucity of sightings on my BBS visits, although they do have that distinctive “tzi tzi derr derr derr” call which can give their presence away. Given the fact that the area appears highly suited to them, I’m looking forward to recording more of this endangered endemic species, and doing my bit to conserve it, in the future.

Great-Spotted Woodpecker

I mentioned earlier that some species present in 1995 are no longer recorded on the survey, but these have been replaced by newcomers.

Great Spotted Woodpeckers appear to have found the maturing woodlands to their liking since I first recorded two in 2006, although I haven’t heard their recognisable “chip” call every year since and I’ve never heard them drumming on the survey. I would imagine I’ll record them more frequently in years to come as the woodlands provide more nesting possibilities. 

Buzzard

Buzzards have undergone a remarkable resurgence, spreading rapidly across the UK in recent years, and this has been reflected in the regularity of their appearance on my recording sheets since 2008. I really enjoy seeing their majestic soaring flight and hearing that instantly-recognisable “mewing” call above the Common, and I’ll never forget the awe-inspiring sight of watching six Buzzards circling overhead in 2017. I look forward to the possibility of seeing them breeding in the woodlands and hearing the distinctive begging call of the young in future years.

...on species totals

I mentioned earlier that 163 species of birds have been recorded at Amberswood. This total is the combination of data kindly supplied by Judith, the Greater Manchester Bird Ringing Group, and the Greater Manchester Local Records Centre. Some of these records will have come from parts of Amberswood that didn’t fall within the boundaries of the SBI when it was designated such in 2004, but as three of the ten sections of my BBS route are outside of what is considered to be Amberswood Common too then I don’t suppose it matters.

In my 26 years of the BBS at SD6004, I have recorded a total of 79 species, which represents 48.5% of the overall species total for Amberswood. Given that records for the entire site go back to 1992 and represent sightings all over the site, not just SD6004, and taking into account that mine come from just two visits-per-year, limited by having to stick to two transects rather than roaming about the square freely, I think my total is respectable.

The number of species I’ve recorded per year, with a maximum of 46 and an average of 39, has been remarkably consistent through the years, reflecting the stable nature of the habitat, even accounting for the closure and capping of the landfill site and the two changes I’ve had to make to my route. If you exclude the four years when only one visit was made, the average rises slightly to 40.5.

…on survey methods

Transect-style surveys are, I’m sure, great for recording species that are easily seen and/or heard like waterbirds or species with loud or distinctive songs and calls but less so for timid, quieter species like Willow Tit or Treecreeper. As the vegetation has grown over the years, I’ve found myself relying more and more on identifying birds by sound rather than sight as they’ve become less and less easy to see. I find being a musician helps a lot in this regard, especially my many years’ experience playing in an orchestra, where it helps to be able to pick individual instruments out amongst the “cacophony” of an orchestral tutti. I’d say that nowadays I identify up to 75% of the species on my surveys by their song or call alone without seeing them.

…changes over the years

The overall site total of 163 includes many species which took advantage of the transient nature of the site in its early days, before reclamation began. Others are from one-off visits from nationally-rare species like Glossy Ibis, Ring-necked duck, Scaup, Bittern, Honey Buzzard, Woodlark and Yellow-browed Warbler, and local rarities such as Red-crested Pochard, Sanderling, Arctic Tern, Hen Harrier, White Wagtail and Twite. In addition to these, a Great Grey Shrike was discovered on Valentine’s Day 2003 and stayed until 29th March, attracting many admirers.

Many species of wader, wildfowl and raptors were recorded by Judith during those early years which are unlikely to be seen now or in such large numbers. Conversely, few could have imagined in 1988 that all that mud and marsh would one day become established woodland and grassland, home to nine species of summer migrant passerines (Reed, Willow, Sedge, Grasshopper, Garden, and one other species of Warbler I’ve yet to tell you about, plus Chiffchaff, Blackcap and Whitethroat) and high populations of many other species of passerines.

Judith visited Amberswood recently, not having been there for five years, and was amazed just how much the plantations had grown in that time, a small slice of the transformation that has been taking place since 1988.

…on new species

I teased you earlier about a species of warbler I’d recorded on the survey.

As I was starting to record section 5 (on the northern side of the railway line, outside of the boundaries of Amberswood Common) on the late visit in 2018, I almost jumped out of my skin when I heard a very loud song from only a few feet away at a reedbed surrounded by scrub.

I didn’t recognise it, and as I was standing right next to some very noisy machinery at work in the adjacent food processing plant, it was impossible to be sure exactly what I’d heard.

I didn’t hear it again and I had to keep walking so it went unidentified. Luckily (though not for my heart), exactly the same thing happened on the early visit a year later and without the noisy machinery hindering my ability to hear it properly.Even though I’d never knowingly heard one before, I had an idea what it could be and a little research on the internet when I got home confirmed my suspicions; I’d heard my first ever Cetti’s Warbler!

cettis_warbler_tony_cox.jpg

Listen to the Cetti's song

cettis_warbler_john_gibson_1_may_2019_sd6004_1.m4a

Audio: John Gibson

Image: Tony Cox

I returned to the reedbed a week later and heard several bursts of song in an hour of observation, during which I made some sound recordings, culminating with a superb view of the “overgrown Wren” singing in the middle of the reeds in plain sight. I heard it again on the late visit and, amazingly, I heard another singing on the opposite side of the tall railway embankment on a non-recording part of my route on the same survey, a road’s width from the official boundary of Amberswood Common.

I soon learned that the species had been recorded singing at the Wigan Flashes as early as November 2007, while Judith tells me there are currently up to 12 territorial males there. There is some suitable habitat on Amberswood and nearby Low Hall LNR so I’m really looking forward to jumping out of my skin many more times on future visits!

So, what of the future? Well, my 1km square was just one of over 4,000 surveyed in 2019 before the pandemic affected surveying a year later, and it gives me a good feeling knowing that I’m doing my bit to help our feathered friends. I don’t expect to be participating in the BBS for another 26 years but I do hope to see more species continuing to thrive on the Common, take my species count over 80 and discover if the changes to the habitat and bird populations I’ve predicted take place. With the continued growth of the coniferous woodlands I hope, one day, to fulfil Judith’s recent prediction of seeing Crossbills in the conifer plantations, and Long-eared Owls nesting in the five owl baskets she erected years ago. I read online that Tawnies are heard calling at the edges of the site so here’s to adding those to my recording sheets in the near future, and lots of Cetti’s too, of course.

I’m indebted to Judith Smith for supplying me with her database of records at Amberswood and for her notes on Amberswood in the early years. I’d also like to thank Steve Atkins and Stuart Fraser from Greater Manchester Ecology Unit for their databases. A big thank you also to Wayne Parry and Richard Broughton for allowing me to use information and data from their amazing Willow Tit project. Finally, I’d like to thank Sarah Harris, BBS coordinator, for suggesting I write the story of my 26 years with the BBS, and BTO Website Editor Miriam Lord for making it happen. I’ve really enjoyed the challenge and it wouldn’t have been possible if I hadn’t been able to download all my data from the data pages of the BBS homepage. Here’s to adding to them in the coming years.

STOP PRESS: On both of my 2021 BBS visits I was treated to a singing Cetti’s Warbler at the edge of Amberswood Lake, almost at the very southern edge of my square, and almost 1km south of the other two locations I’ve previously heard them. My hopes and predictions are coming true already! Ain’t birding brill?