A total of 43 species of hoverfly were recorded compared with 54 seen in 2019. Several regular species of the genus Cheilosia and Platycheirus, that are mostly prevalent in Spring, were not seen this year.
The first hoverfly of the year was a Common Dronefly Eristalis tenax in February, followed by Tapered and Plain-faced Dronefly Eristalis pertinax & arbustorum, Marmalade Hoverfly Episyrphus balteatus and Platycheirus scutatus by early March.
Some hoverflies are highly migratory and numbers can be noticeably boosted by influxes. On 13 June hundreds of Marmalade Hoverfly were on site with lesser numbers of White-clubbed Hoverfly Scaeva pyrastri. By mid August other migrant hoverflies such as Large Tiger Hoverfly Helophilus trivittatus and Syritta pipiens had begun to arrive, sharing Water Mint and Common Fleabane with Batman Hoverfly Myathropa florea, Hornet Hoverfly Volucella zonaria and Giant Pied Hoverfly Volucella pellucens.
Other nectaring hoverflies seen at this time included Common Tubetail Sphaerophoria scripta, Humming Syrphus Syrphus ribesii, Tiger Hoverfly Helophilus pendulus and Stripe-faced Dronefly Eristalis nemorum.
Only one new species was recorded this year, Rural Bulbfly Eumerus strigatus on 12 September. Although there was a lack of new species, several hoverflies confirmed their continuing presence following their first occurrence in 2019.
These included Hook-banded Wasp Hoverfly Chrysotoxum festivum, Common Thistle Cheilosia Cheilosia proxima and Parsley Cheilosia Cheilosia pagana in June, Broad-banded Epistrophe Epistrophe grossulariae and Golden-tailed Hoverfly Xylota sylvarum in July, Lesser Hornet Hoverfly Volucella inanis in August and Yellow-barred Peat Hoverfly Sericomyia silentis in September.
Throughout October hoverflies species started to dwindle, although Common Dronefly were still plentiful on bramble and ivy until the end of the month. By November hoverfly numbers had dropped off considerably with just single sightings of Melanostoma scalare on 19th, Common Spotted Field Syrph Eupeodes luniger and Humming Syrphus on 21st, and Marmalade Hoverfly on 26th. The last hoverfly of 2020 was a Glass-winged Syrphus Syrphus vitripennis on 19th December.