Askham Bog YWT


Site Details: 

Recorders: David Firth + Richard Leatherly , Lizzie McFarlane          Distance: 1200m              Walk Time:  50 mins    Altitude  15m. 

Askham Bog is small area of peat bog and Site of Special Scientific Interest situated within the Vale of York in North Yorkshire, England. It lies to the south-west of York, north of Copmanthorpe and near Askham Richard and Askham Bryan. It is regarded as one of the most ecologically diverse sites in Northern England

Askham Bog is remarkable survivor of the ancient fenlands of Yorkshire. It occupies the site of an ancient lake, left behind by a retreating glacier 15,000 years ago - the low hill to the south of the Bog, along which the A64 road runs, is the terminal moraine from that glacier. 

Dating back to Roman times Askham Bog was used by local communities as a source of peat for fuel, resulting in a mosaic of habitats and a legacy of ditches, probably originally used for peat extraction.

It was purchased  by YWT in 1946 and restored to ts original state as a wildlife reserve 

Magnificent royal ferns, rare gingerbread sedge and spectacular displays of water violets are to be found in this mosaic of fen, woodland and meadow. 


S1 is largely wet woodland and section 2 3 and 4 are raised walkways with small meadow areas to their south  and section 5 has meadow areas to its north. S6 is a more open  meadow area while 7 and 8 are part raised walkway  and rather shady

No section habitat details have been entered in UKBMS

Comma is seen in S6-8 while Gatekeeper tend to frequent S2, 5 and 6 . Whites are farely uniform across the site. The little meadows of S2-5  see large Skipper and Ringlet. Meadow Browns favour S2 and 6.  Peacocks also favour the more open S6 along with Tortoiseshells. Small Skipper is most frequent in S4-5 while the shade loving Speckled Woods S7+8. The wall has been seeen on occasion lately in S5

2023 Results 

County wide 2023 results reflect  the 2022 and  2023 spring drought with Small Tortoiseshell and Peacock nearly halved for the second year against their 5 year average. Red Admiral arrived in force in July and took advantage of soft nettle growth of the rains and had their best year ever. Drought sensitive species on thin soils were badly hit,  particularly Dark -green Fritillary and Northern Brown Argus but also Ringlet, Green-viened White and Small Heath.  Less drought affected species along with the hottest June on record built even more on gains last year leading to Comma, Brimstone, Holly Blue and most Browns  having a fantastic year reaching all time highs. A increase of 9% overall was mostly due to sheer numbers of Meadow Browns and Gatekeepers ment 2023 nearly pipped 2014 as best year in modern times.  Most noticeable was the large differeces between mositure retaining mineral soils of the valleys and thin, dry limestone or sandy soils. A large number of damp grassland, hedgerow and woodland  dominated sites benefitted hugely with 3 sites seeing more than 50% increase . A smaller number of thin, chalky, sandy or craggy sites did badly some down up to 25%.

2023 results at Askham Bog  reflect the county trends  along with the change in route which brings in more grassland  and their species and less woodland so increasing overall numbers by 33%  a good part due to sheer numbers of Gatekeepers which had its best year ever.

Transect reports 2020

2022 Results 

Has had another rather poor year so while most sites were close to average Askham was noticeably down and sufficient to raise concern by the walkers that the route habitats have changed with much more shading in places and a reroute is being considered. However when you compare to  a similar close by site Bishop Wood then there are  some similarities with small skipper being well down. However the whites here seem to have suffered a good deal more with only Green viened up as in Bishop wood. Holy Blue follows the county trend in being up significantly  but all the Vannesids down although for most sites Comma at least was up.  Speckled wood up as for most sites as was Gatekeeper matching the county trend  Ringlet was well down as at Bishop wood and seperates it from the county trend which was up. 

2021 Results 

Results are in line with other transects in 2021 with a poor showing from Small Skipper, Small  White, Large White Red Admiral and particularly Comma , The two winners were Small Tortoiseshell and Gatekeeper  along with Brimstone, Green-veined white  and Orange tip.  Meadow browns have been more common the last two years.  Speckled wood also had a very poor year as in other transects.  Overall numbers were down rather more than elsewhere but it is difficult to be sure due to lack of walks.

2020 Results

2019 was always going to be a tough act to follow and numbers were slightly down after adding estimates for lockdown.  Comma and Speckled wood  and all the  whites and Brimstone were  down.  However there were more Meadow Browns and a boom in Gatekeeper and Small Skipper and in common with all other transects Small Tortoiseshell had there best year for some time.