The Holly Blue, Celastrina argiolus

The Holly Blue is not a very common butterfly in Yeldham, at Roseland House a few individuals may be seen in a year, or none at all.

Two broods are produced per year. After overwintering as pupae, adults emerge in early April and lay their eggs on Holly. There is a lull of adults on the wing in mid June to mid July before the next brood emerges in later summer to lay its eggs on Ivy where they will hatch, feed as larvae and pupate before the coming winter.

Weather notes:
2011. July - early August very wet.
2012. April - mid July very wet. August to mid September dry.
2013. Winter wet, March and early April, very cold. The rest of the spring was mostly cold. July, mostly very warm. August, warm.
2014. Winter very wet, mild. Spring was early, colder in mid April. Summer to early August, warm without a drought.
2015. Winter normal, March, April - May mostly cold. Sallow flowers opened on March 28 - 29th. Summer, fairly normal.
2016. Winter normal. Sallow flowers opened on April 2 - 3rd. Spring mostly cool and breezy. For a few weeks in late spring there was heavy rainfall and saturated soil and vegetation. Late summer with hot, dry periods.
2017. Winter mildish, hardly any frost. Sallow flowers opened on March 14 - 15th. Warm spells in March. April mostly dry and chilly. First Creeping Thistle flowers open on June 13th, followed by about 7 days of heat wave. Early July was very warm, excellent for counting butterflies. Late summer, autumn normal.
2018. Winter normal with a few days of settled snow. Sallow flowers open on March 26th. March, April mostly cold and wet, May warm. June 11, Bramble flowers opening to greet first Large Skippers. Mid June to early August, very hot and dry. Autumn mostly dry.
2019. Winter normal. Hardly any frost. Sallow flowers seen on March 10th. Spring mostly cool apart from Easter heatwave. May 31, Bramble flowers starting to open. June 1, Buckthorn in full bloom. Dryish summer with some heatwaves.
2020. Mildish winter. Sallow flowers open March 10th. Spring mostly cool. Several warm days in early April and through May. May 28 Bramble flowers opening. Record dry May. June nectar sources mostly Buttercups in the unmown paths, and Brambles.
2021.Winter normal. Very wet, early spring then cold. Sallow flowers opened on March 23rd. Summer with a few hot spells and moderate rain.
2022. Winter, normal. Sallow flowers open on March 18th. Bramble flowers open May 28. Summer, mostly very dry with long hot spells.
2023. Winter normal, some frost. Feb very dry, March very wet. Sallow flowers open on March 21st. Cold wet spring followed by hottest May on record, warm June and wet July. Autumn, mild and wet.
2024. Winter mild and wet. Feb very wet. Sallow flowers open on March 13th. April record rainfall. Late summer, early autumn much dryer.

Other personal sightings:

17 July 2010. West Stow, Suffolk. 1 Holly Blue.
6 April 2011. Fleam Dyke. In the wooded section towards Balsham, 1 Holly Blue.
5 May 2013. Fleam Dyke, west end between the A11 and the railway cutting. 4 Holly Blues.
4 June 2013. Hitchcock's Meadows, Danbury. 1 Holly Blue.
18 July 2014. Clare Country Park, Suffolk. In the car park. 1 Holly Blue.
10 May 2015. Birdbrook. A green lane near the village centre. 1 Holly Blue.
22 Aug 2015. Fleam Dyke. By the A11 lay-by. 1 Holly Blue.
28 Aug 2015. Great Yeldham, Tilbury Road, Mill Cottage drive. 1 Holly Blue, female on Ivy.