Main Bay Heath RSPB
Pontefract
Site Details
Recorders: Rachel Tulloch Distance: 1400m Walk time: 1 hour
Shaped by a long history of coal mining, Fairburn Ings protects a mixture of habitats. Wetland areas created by subsidence include open water, wet grassland, reedbed and wet woodland. While other habitats, including dry grassland, deciduous woodland and lagoons, have been restored on the former coal spoil tips.
This is a grassalnd area under restoration over magnesian limestone . There are large areas of scrub.
Sections
S1 Grassland has good numbers of Meadow Brown and Common Blue.
S2 Has little currently.
S3 is good foe Ringlet and Gatekeeper
S4+ S5 is very good for Common Blue
S5-S6 are best for Large and Small Skippers
S8-10 are generally poorer for species until things improve in S11
Results: 2024
Countywide, after a warm winter April turned cold, very wet and dull and everything just about stopped and it was near impossible to transect walk all month. By May there were already losses among our spring species being down a third in numbers. June brought Arctic winds, a complete reversal of the Hot June of 2023 when nine species reached all time highs here and across the UK. For the first two weeks of this June temperatures were 8’C cooler than in 2023 around a frigid 9’C with only 5 good days of sun at the end of the month. The first three weeks of July had the same theme of cool and damp with 5 warm sunny days at the end. Transect walking for many was very difficult. The persistence of the cold and damp over such a long period had a devastating effect with numerically two thirds of our butterflies in the critical later stages of their development; mortality was very high. It was also one of the longest June ‘Lulls’ lasting from late May to the beginning of July. When the main flight season did arrive it was slow to build up and there was no usual peak. Better weather in August helped save the second generation and very unusually numbers actually went up at the start of September.
Losers
For many species it was a triple whammy after the heat and droughts of the previous 2 years and last July’s poor flight period this year made it a perfect storm. Overall, annual numbers were down 41% against the average and 45% down on last year. Half our species were down more than 50% and a quarter down more than 70%. The Lycaenids, Vannesids and the Fritillaries were amongst the worst affected. Many transect walkers did not see a single Common Blue, Small Copper, Holly Blue, or Brown Argus until late into their 2nd broods.. Four of our long term declining species Common Blue, Small Heath, Small Skipper and Green-veined White had their worst year ever recorded.
The Winners and less bad losers
Northern Brown Argus had an exceptional year up near 50% Other species bucking the trend were Brimstone and Marbled White. The damp loving Ringlet on many limestone/dry sites were up a half while on most wet sites they fell by a half. However if it wasn’t for Ringlet holding up the overall numerical losses, this year would have been significantly worse. It often happens when Meadow Brown has a very poor year, like this one, Ringlet does proportionally better, and vice versa in a warm year.
It has all happened before… many times.
It was our worst year since 2016 but nearly as bad as 2009 when numbers were down 50%. 2024 comes after a run of 6 relatively good years since 2018 along with rapidly rising temperatures including 2 of our hottest summers which were followed by two of our best butterfly years in 2019 and 2023. It is likely 2024 was a blip
Main Bay Heath had a pretty good year in comparison to the county average. The figures suggest it is recovering from drought with teh browns not down very much and teh damp loving Ringlet having 4 times as many as last year! The vanessids and Blues were really badly affected however. Dingy did well here maybe because of recovery of BFT Only the peacock by proportion was less badly hit, and, as with so many sites, not a single Small tortoiseshell was seen. Brimstone did well as they did almost universally and the whites held their ground.
Results: 2022
Overall a bit down on the previous 2 years. However its good to see Dingy Skipper feauture. Brimstone numbers well up this year and the county trend was also up while most of the whites were down. Similar to other sites most of the blues and teh vanessids were down. The browns were mixed while on most sites they were well up. In common with elsewhere speckled wood saw a very large increase particularly in September.