Survey – WHBBS

Wealden Heaths Breeding Bird Survey (West Sussex)
2022 Results (25th Year)

 

The attached graphs show the overall WHBBS trends, and the schedule provides the details of the surveyed species on each site. The following is a short commentary on the individual target species and a brief note regarding the other species monitored. The surveyors log males holding territory and breeding proof is not required although surveyors can often provide this information. The aim is to gather data over a long period to assess population trends on the West Sussex Wealden Heaths. The surveyors log their records within 1km squares and these results are entered onto the secure SOS database making the data available for landowners, managers and researchers. Compared to the much larger heathland areas in neighbouring Hampshire and Surrey the Sussex western heaths are both small and largely isolated from each other, it is therefore essential that monitoring continues to assist managers and owners in their efforts to retain and improve these fragile and rare heaths.

When the survey was set up a number of marginal sites were included many being wooded heath subject to occasional forestry clearance work before replanting. These areas are retained on the schedule in case of future restoration to open heathland but also as a reminder that when clearance does occur there is window for open heath species to move in. The survey itself comprises the ten heaths that have been monitored for the full 25 years (Iping and Stedham are treated as separate heaths), plus the later additions of Broad Halfpenny and Graffham Commons. These two latter sites are not recorded on the graphs.

Of the five target species, Nightjar, Woodlark, Stonechat and Dartford Warbler numbers are all holding up well and reference to the graphs show upward trends; Tree Pipit however continues to decline.

Target Species comment.

Nightjar Caprimulgus europaeus
2022 was yet again a good year and at 65 territorial males it overtook 2021 (59) which was the previous best year in the 25 years of the survey. Ambersham/Heyshott Common (18) remains the prime site followed by Iping/Stedham (12), Black Down (10), Lavington (9) and an encouraging six were found on Woolbeding. All of the remaining sites had at least one territory, a most successful year for this migrant species.

Woodlark Lullula arborea
A mainly resident species that forms small, often family flocks in the winter. A count of 53 territories (44 last year) takes this species almost back to numbers found 1998-2000, which was a period when there was very extensive clearance and restoration works undertaken on the heaths, providing ideal conditions for the species. Although such major works are no longer in evidence continuing good management practice has undoubtably been an issue in their steady population growth, particularly over the last 10 years.

Tree Pipit Anthus trivialis
A migratory species, whose population once numbered 81 territorial males on our heaths. Last year it was noted that numbers seem to have stabilised at 20-30 territories but a count of 19 this year was very disappointing. Only Iping/Stedham (7), Ambersham/Heyshott (4) and Black Down (4) had counts of over two and this remains a worrying decline since the peak in 2000. Although numbers have increased in Scotland the decline in England has made it a Red-data species of conservation concern. Although there is a case for surmising the problem is a lack of suitable habitat in the UK it is certain that most of our heaths have excellent habitat for the species, thus the suspicion falls onto problems during migration and at wintering sites with climate change and habitat degradation in Africa being possible negative factors.

Stonechat Saxicola rubicola
A mainly resident species as most over winter in the UK whilst only a few migrate to the Mediterranean area. Some remain on the heaths throughout the winter period. This was the best year of the survey with 69 territories identified and only Lynchmere/Stanley reporting none. Ambersham/Heyshott with15 was the prime site but closely followed by Weavers Down (12),Iping/Stedham heaths and Black Down held 11 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 territory was recorded. The territories increased to 49 and levels are beginning to return to the numbers found prior to the 2011 wipe out. The steady increase is likely to be due to less severe winters and continuing management work. Particularly encouraging were the 9 territories found on Chapel Common, as this site is one of the most used for leisure activities, particularly dog walking.

Of the other species monitored and shown on the graphs Woodcock Scolopax rusticola, Green Woodpecker Picus viridis, Great Spotted Woodpecker Dendrocopus major, Redstart Phoenicurus phoenicurus, Whitethroat Curruca communis and Linnet Linaria cannabina remain relatively stable. Although overall numbers also remain stable for Yellowhammer Emberiza citrinella, it is noticeably absent from the four northern heaths of Weavers Down, Lynchmere/Stanley, Black Down and Chapel Common. However, there was an exceptional count of 22 on Woolbeding.

Stock Dove Columba oenas had yet another good year matching the 30 of last year.

Not shown on the graphs for reasons of low numbers are Hobby Falco subbuteo and Reed Bunting Emberiza pusilla (although this was an exceptional year for the latter species with five reported from Coates/Lords Piece and three from Iping).

Siskin Spinus spinus and Lesser Redpoll Acanthis cabaret (4) do breed in small numbers each year and as an exception to the aforementioned comment, 2022 was the best Siskin (21) year of the survey.

Crossbill Loxia curvirostra is an irruptive species and breed irregularly in the pines either beside or on the heaths this year there were an estimated 13 territories, nine of which were on Black Down.

Heathlands

Weavers Down, Chapel Common, Lynchmere/Stanley Common, Black Down, Stedham Common, Iping Commons, Woolbeding Common, Ambersham/Heyshott Common, Lavington/Plantation/Duncton Common, Coates/Lords Piece.

Additional to original heaths are Broad Halfpenny and Graffham Common.

Weather Synopsis for survey period. The annual survey commences mid- February to identify Wood Lark as they set up their territories and ceases in mid-July. Overall the weather did not prove a problem this year although the extreme temperatures just after mid July did provide ideal fire conditions. It appears we have been lucky and avoided any such conflagrations.

February The weather at the beginning of the month was quite settled and mild, but it soon became much more unsettled, with a succession of depressions bringing rain across much of the country, and a particularly stormy spell between the 16th and the 21st which included three named storms. It remained mostly mild, however, especially in southern areas, with few frosts. March The first few days of the month were rather cold, and the first half was generally unsettled, but it became milder, and high pressure took charge from mid-month with sunshine becoming plentiful. The end of the month was less settled and much colder. As it was mild for the majority of the month, mean temperatures were 1.1 °C above average.. Rainfall was near average in some areas, but rather below normal in the far south-east, giving 72% overall. Sunshine was above average. April The first few days of the month were rather cold, and most of the month’s rainfall fell within the first week. After that it was settled for most of the time, and rather warmer between the 12th and the 24th, but temperatures fell back during the final few days. The settled weather meant that both sunshine and air frosts were above average. Mean temperatures for the month were just 0.2 °C above the 1991-2020 average, helped by daytime temperatures being rather elevated. It was a drier than average month, with less than a third of average rainfall in many places. giving overall just 44% of average. May This month was rather quiet generally, mostly on the warm side except for the latter part, though never totally settled, with showery rain at times throughout and thunderstorms on numerous occasions. Mean temperatures for the month were 1.2 °C above the 1991-2020 average, with eastern areas being warmest relative to normal. Rainfall was near normal generally. Sunshine was near normal in some eastern and southern counties but below normal elsewhere. June saw plenty of fine and settled weather, but also some showers during the first week and the final week. Around mid-month there was a short very warm spell, felt most in south-eastern areas. Overall it was slightly warmer, drier and sunnier than average. Mean temperatures for the month were 0.5 °C above average, with eastern areas being warmest relative to normal. Maximum temperatures were over a degree above normal in eastern areas, while minima were just below average in parts of the south. Rainfall was below average in many areas. Sunshine was broadly above normal, again with the east faring best, giving an overall figure of 118%. July The month began rather cool with a few showers, but within a week it was settled and became increasingly warm. Temperatures exceeded 30 °C in a few places on the 10th, but it was the spell around 18th/19th that broke temperature records, with the UK’s first ever readings above 40 °C. Rainfall was generally below normal for the month, with very little rain in parts of the south and east. .
(Weather details from Met Office)

Alan Perry WHBBS Organiser

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