Survey – WHBBS

Wealden Heaths Breeding Bird Survey (West Sussex)

 

2021 Update

Overall this has been a reasonable to good year for many of the species the subject of the survey. Of the five main target species Nightjar and Dartford Warbler continue upward trajectories, Stonechat and Woodlark remain largely static and even Tree Pipit seems to be holdings its own albeit at historically (over the 24 years of the survey) low numbers.

The attached graphs show the overall WHBBS trends and the schedule provides the details of each site. The following is a brief comment on the individual target species and a note of any other interesting trends. Please note that the survey logs males holding territory and breeding proof is not required although surveyors often provide this information. The aim is to gather numerical data over a long period which we can use to assess population trends. The surveyors log their records within 1km squares and these results are entered on into secure SOS database making the data available for land owners, managers and research. Covid did not impinge in any meaningful way upon the survey this year.

Weather. The annual survey commences mid-February to identify Wood Lark as they set up their territories, but the weather of the earlier winter can cause problems for our resident species. Worryingly the mean January temperature for that month was 1.2C below the1981-2010 long-term average, the coldest since 2010. February commenced mild but there was a bitter spell with some areas receiving snow before milder weather moved in and by the end of the month England had experienced 121% of average rainfall. March began mostly settled but rather cold before turning milder but windy. It ended very warm in some areas and overall, England received 78% of average rainfall. April was extremely mixed with the month recording temperatures below the 1981-2010 long-term average by 1.9C, the second coldest April in a series since 1884, but it was also the seventh driest recorded since 1862 whilst sunshine was the second highest since 1919. Very much a mixed bag! May was unsettled and windy with a brief warm spell but rain was the over-riding feature with 191% of the average, whilst temperature was 1.3C below the long-term mean. June was predominately warm and dry to start but there were episodes of torrential rainfall resulting in the south-east experiencing over double the average but additionally the mean minimum temperature was the second highest recorded since 1884. July was entered with continuing unsettled weather although it did warm up mid-month. (Weather details from Met Office).

Despite the unsettled and gyrating nature of the weather during our survey months the birds appear to have shrugged off the colder and wetter periods and, as will be seen from the graphs and commentary below, had a largely successful year.

Target Species comment.

Nightjar Caprimulgus europaeus
2021 was the best year since the beginning of the survey for this species: 59 in total. The best site is Ambersham/Heyshott Common with 18 churring males followed by Iping (10), Lavington (8) and Black Down (6). In contrast it is very disappointing that none were found on Lynchmere/ Stanley Commons. It is possible that visitor pressure is the problem here. However, both Black Down and Iping are also visitor hotspots and despite this the species shows annual resilience on these heaths. Overall, it was a successful year for this migrant species.

Woodlark Lullula arborea
A mainly resident species that forms small, often family flocks in the winter. A total of 44 territories confirms the species continues to hold its own on the heaths. There is no doubt that continuing management is extremely helpful to the species as it prefers mown swards, bare areas with tussocky outcrops etc. It mainly eschews dense heather beds except where bare and short sward areas are formed. Recorded on all 10 main heaths; Iping (10) and Black Down (8) hold the largest populations.

Tree Pipit Anthus trivialis
A migratory species, whose population which once numbered 81 territorial males on our heaths, that has declined substantially but has stabilised since 2009 at between 20-30 territories; the count for 2021 was 21. Recorded on six of the heaths only, it appears to be particularly resilient on the north-west heaths of Weavers Down, Chapel, Lynchmere/Stanley and Black Down Commons however Iping with five has the largest single population. Lavington, which once held a very healthy population, has been abandoned since 2016.

Stonechat Saxicola rubicola
This species is also a resident with some birds over-wintering on the heaths and others wandering further afield. Numbers for the past three years have remained static at 49 territories. Recorded on all main heaths, numbers were particularly encouraging on Ambersham/Heyshott which held 14 territories followed by Black Down and Iping with 10 each.

Dartford Warbler Curruca undata
Usually resident on the heaths throughout the year the species is susceptible to severe winter weather as happened in 2011 when only one was recorded. Since that date numbers have increased regularly and, whilst not approaching the peak of 70 territories in 2003, a population of 41, and with an upward trend is an encouraging sign.

Of the other species monitored and shown on the graphs it is apparent that Woodcock Scolopax rusticola, Green Woodpecker Picus viridis, Great Spotted Woodpecker Dendrocopus major, Whitethroat Curruca communis and Linnet Linaria cannabina remain relatively stable, as is Yellowhammer Emberiza citrinella but with perhaps a worryingly regular, albeit slight, decrease. Stock Dove Columba oenas stands out as having had an exceptional year at a figure of 30 and after a pause of five years Redstart Phoenicurus phoenicurus numbers have rebuilt in 2021 to 19. This is not a common species on the Sussex Wealden Heaths.

Some species such as Hobby Falco subbuteo and Reed Bunting Emberiza pusilla have such low numbers they are not shown on graphs. However there are irruptive species such as Crossbill Loxia curvirostra that breed irregularly in the pines either beside or on the heaths and (2021 was a good year for this species with an estimated 19 territories, with the high heaths of Black Down and Lynchmere/Stanley being the favoured sites). Two other species, Siskin Spinus spinus and Lesser Redpoll Acanthis cabaret, are often in evidence in small numbers throughout the year and breeding is suspected more often than confirmed.

Alan Perry WHBBS Organiser

 

2020 Update

Naturally surveying was limited and so this year there will not be the usual graphs. I have commented briefly on priority species which did receive either full coverage on their heaths (daily form of exercise) or could be fully surveyed before lock-down (Yellowhammer) or after lock-down (Nightjar being the prime example). Full or limited data was received from all heaths except Broad Halfpenny and Coates/Lords Piece.

The annual survey commences mid- February to identify Wood Lark as they set up their territories. Regrettably this year the month tended to be stormier and wetter than usual and this weather was with us upon entering March but the remainder of the month was drier. Lock-down began 23 March and only Black Down and Ambersham/Heyshott were able to be visited in each month under the daily exercise allowance. With the raising of the severest restrictions in early May most surveyors recommenced their work. April had been warmer than average (fifth warmest since 1884) and, other than a cold spell in mid-month, May was largely dry and warm. June was wetter than usual but with a slightly higher mean temperature. July was cool, changeable and cloudy for most of the month, but ridges of high pressure brought dry sunny weather mainly to the south at times, it briefly turned very hot in central and eastern areas on the 31st. (weather details from Met Office).

It was anticipated by the surveyors that it would be a good year for our heaths as far as activity levels were concemed, especially dog walking. In reality even April, which was the quietest month, was subject to “daily exercising” and after May 10th many people, being either furloughed or working from home, were enjoying the heaths, leading to activity levels either the same as usual or on the more popular heaths especially, greater.

The overall picture for the heaths where comparisons could be made, indicate that for the five priority species, Nightjar, Woodlark, Tree Pipit, Stonechat and Dartford Warbler there were no great fluctuations in numbers. Black Down did record 12 Tree Pipit territories against seven last year and a welcome count of 14 Dartford Warbler territories (10 in 2019). Yellow Hammer showed great variance with only Iping/Stedham (11), Ambersham/Heyshott (2), Lavington (6) whilst Woolbeding (16) reporting them present.

The results we have received this year will stil be logged in the SOS database and also sent to the owners/land managers/experts as usual.

Alan Perry WHBBS Organiser

 

2019 Update

A mixed bag of weather (as usual) was evident through the survey season. My notes show some clear days at 11c in mid-February rising on the 29th to 20c. Overall spring temperatures were slightly higher than average but a very wet period in March (the UK’s 5th wettest March on record) undoubtedly affected some early breeders. April commenced rather chilly but became warmer with temperatures in the 20c’s at the end.  Early May returned to cool but warmed up during the month and June into July saw daytime temperatures well above average. Most of July was extremely dry (UK receiving 71% of average rainfall).

For our five priority species, Nightjar, Woodlark, Tree Pipit, Stonechat and Dartford Warbler it was a reasonably successful year with all showing a slight increase over 2018 figures.  Particularly encouraging was Tree Pipit and although it was only a small increase from 16 in 2018 to 19 in 2019 this hopefully will be a reversal of the recent declining trend; however the national picture is that the population is contracting in south- east England, occurring at its greatest abundance in Wales, northern England and Scotland. Black Down with a count of seven remains our most successful heath. Also encouraging is the continued resilience of the Nightjar and Woodlark populations throughout the 22 year survey period.  Perhaps indicating that despite greater leisure activity pressure (especially as our heaths are now in the South Downs National Park) ongoing management ensures favourable habitat conditions for breeding. Likewise Stonechat and Dartford Warbler continue to increase their numbers recovering from the terrible winter of 2009/10, the latter however is only a slow increase, perhaps a good summer breeding period will provide the impetus for  a return to the upward surge in numbers seen during the early years of this survey . The increase 2018 to 2019 was 21-34.

It will be noted from the graphs (click here) that the only declines this year were from three of our most successful species – Green and Great Spotted Woodpeckers and Stock Dove. however I doubt this is statistically meaningful but obviously future surveys will check for any adverse trend. Redstart, apart from the outstanding year of 2015,  remains consistently, since 2011, in the 10-15 range. To encourage breeding a nest box scheme is being considered at Lynchmere/Stanley. Perhaps this could be expanded into other heaths particularly those situated on the high ridge area.

Whitethroat retains a steady population as do Linnet and Yellow Hammer, the former (Linnet) with an increase 44-52. Woodcock remains a difficult species to survey unless roding birds “meet up” but the estimate of 14 is within the 10-15 range that has been reported since 2011.

The remaining species within the survey have either provided nil results or their numbers are too low to warrant graphs. However, it was pleasing to have three Crossbill reported after a negative 2018.  Black Down and Lynchmere appear to be the most reliable sites for this species when it does stay to breed, followed by Lavington and Ambersham/Heyshott.

Reports from surveyors reported on-going management but the principle concern, as noted last year is of disturbance. Dog walking or rather free-range dogs being the main culprits particularly where dog-sitters exercise a “pack”. As I reiterate each year our Wealden Heaths are very small, dislocated and fragile and it is only through careful and sensitive management (including education of the users) that we can ensure their future sustainability.

I think it worth noting that these results are not just recorded by the SOS but relevant details are sent to the owners/land managers/experts to provide information for future management.

Alan Perry WHBBS Organiser

 

Background to the survey

Originally the Wealden Heaths and Thames Basin Breeding Bird Survey was set up in 1997 as a collaboration between four county ornithological societies to monitor the important heathlands of West Sussex, Surrey, Hampshire and Berkshire. These included some of the Wealden heaths, designated as a Special Protection Area (SPA) in 1994 (Phase I) and 1998 (Phase II), and the Thames Basin heaths, designated as an SPA in 2005. There are no immediate plans by the statutory authority to implement a Phase III to include the West Sussex group of Wealden heaths. Nevertheless, the Wealden Heaths Breeding Bird Survey (West Sussex) is continuing with the objectives of providing data to assist in management decisions and to enable results to be measured thereafter, to provide a long run of data to help protect the sites from damaging developments either within or adjacent to them, and to ensure that results are retained in the Sussex Ornithological Society database.

Currently fourteen heaths (Iping & Stedham are recorded individually) are regularly monitored and include recently Graffham, Midhurst and Broad Halfpenny. West Heath was formerly monitored but is now largely a sand extraction site, however it is hoped that when the work ceases it will be returned to an actively managed heathland site.

Twenty-one bird species perceived to be specialists of the habitat or typical users were chosen as the subjects of the survey and of these Nightjar Caprimulgus europaeus, Woodlark Lullulu arborea, Dartford Warbler Sylvia undata, Tree Pipit Anthus trivialis and Stonechat Saxicola torquata were considered priority species.

Although these five species are our main quarry the recording form enables us to monitor the remaining species which include Yellow Hammer, Redstart, Linnet and other typical heathland birds (sadly Turtle Dove has not been recorded for many years). A brief schedule of the results are published in the Sussex Bird Report annually.

How can you help?

Although we have surveyors for the sites currently there often problems and we have to ask urgently for a new surveyor or a temporary surveyor is needed to cover a heath due to illness etc. If you would like to help then please contact the coordinator Alan Perry for further information (see below for contact details).

The format of the survey is as follows :

The Survey starts in mid- February, (to find the Woodlarks taking up their territories) and carries on until late June. We try to cover the individual sites entirely on four occasions, including one early visit as mentioned, and two visits (more if you have the inclination and the time), about two weeks apart during May when song activity is at its peak. There will be at least one evening visit (preferably two) in May and/or June to count Nightjar.

With the data collected we are able to estimate the total number of breeding pairs/territorial males of each species and assess the success or otherwise of these birds over a long time frame.

The heathlands we cover are as follows:

Weavers Down
Chapel Common
Lynchmere & Stanley Commons
Black Down
Iping Common
Stedham Common
Woolbeding
Ambersham & Heyshott Commons
Lavington & Duncton Commons
Coates & Lords Piece
Recent additions: Graffham Common, Broad Halfpenny.
Currently not viable – West Heath.
Currently vacant Hesworth Common. A small village-owned heath.

For more information or if you wish to volunteer please contact the organiser Alan Perry on 01798 344417 or by email ap@alanperry.uk.com

A paper of the survey 1998-2015 was published in the Sussex Bird Report 2016 entitled “Wealden Heaths Breeding Bird Survey (West Sussex) 1998-2015”. The paper included heathland background information, site descriptions and notes on wintering birds.

An extended version of this paper including a preface, site maps, management issues and bird photographs, taken mainly by Sussex birders, is available by email from Alan Perry apply ap@alanperry.uk.com.

 

The survey is ongoing

Alan Perry
WHBBS Organiser