26th April 2020

We have started seeing our first Holly Blue butterflies so it is time to feature this delicate, tiny butterfly again. Much more common in the south, the Holly Blue has been spreading north and we see it in Sheffield every year now. It is the first Blue butterfly you will see, and flies up in the shrubs and trees, not near the ground and grasses like later blues. As this small (about 1.5 cm at rest) butterfly speeds in a mazy flight it can appear  very pale and then flash blue- the upper wings are bluer and the males a stringer blue than females, with a dark wing edge ( see photos). It has two generations, spring feed on holly, spindle (which we have planted in our garden as it is a favourite of mine) etc and the summer generation on dogwood and bramble. Numbers vary each year because there is a parasitic wasp, (Listrodomus nycthemerus) which only preys on Holly Blue, and it depends how prevalent the wasp is. Hard to see in detail, try noticing where the is little flake of a butterfly rests and warms up, usually a few feet off the ground. You are in for a treat if you do, or just enjoy it flitting through the garden or local park.  Conditions: slightly cooler  and cloudier after many hot and dry days.

Male Holly Blue

Holly Blue at rest

Holly Blue- female

Temperature: Max 18 Min 8 C. 

30th April 2019

The Holly Blue Butterfly– this is the most likely of the Blue Butterflies to be seen in our gardens- it is certainly flying its high, fast flitting flight in our garden again now. If you see a small, sky-blue butterfly, almost like a petal being blown in the wind, it will be the Holly Blue, as all other Blues emerge later, and fly lower. It has dark wing-tips and pale undersides, if you manage to get a close view- see the photo’s (which, because it doesn’t settle much are very hard to get!). The Holly Blue lays its eggs, first generation on Holly buds, usually in the sun, and second on Ivy. The population levels fluctuate widely, mostly due to the occurrence of a parasitic wasp, Listrodomus Nycthermerus.

Holly Blue

Holly Blue

Holly Blue

This wasp lays an egg in the Holly Blue Larva, and emerge as adults from the Chrysalis. Conditions: Sun and cloud after mist. Temperature: Max 17 Min 9C.

24th July 2017

The small, beautiful Holly Blue butterfly,  the only blue we get in our garden and the one you are most likely to see in parks and gardens in England and Wales, flitting low and fast, is back feeding on our flowers. Numbers of Holly Blue fluctuate greatly, thought to be due to the variable numbers of the parasitic wasp which lays its eggs in their caterpillars. The caterpillars feed on holly as the name suggests, but also on dogwood, spindle, snowberry and other common bushes. The female has a dark edge to the wing. Conditions: cloudy after heavy rain. Temperature: Max 19- Min 13 C.

Female Holly Blue

Holly Blue

Female Holly Blue butterfly

17th April 2017

Holly Blue Butterfly- This is a good time to learn to identify the small Holly Blue. It flies high among bushes and hardly settles -you tend to see is a fast-moving blue flash (very hard to photograph!). The underwings are paler. Holly Blues are out earlier (out now) than other Blues, and much more likely to be the Blue Butterfly you see in your garden or local park or verge. They are the only Blues we get in our Sheffield garden. The caterpillars feed on tender new Holly or Spindle shoots and buds. A real treat- keep your eyes peeled. Conditions: Cloudy, with some sun. Cold nights predicted. Temperature: Max 11- Min 2C.

Holly Blue

Holly Blue

Holly Blue- dark wing-tips and spotted underwing

16th August 2016

Holly Blue Butterfly- If you live south of a Cumbria/`Durham line, and you see a fast-moving blue Butterfly zig-zagging through your garden or park it is most likely to be the delicate Holly Blue. Hard to photograph, this female of this blue Butterly has a dark edge to its forewing. The larvae, which feed mainly on Holly, Ivy and Spindle are parasitised by the Ichneumon Wasp. causing huge variations in populations from year. We have only seen one this year in the garden, but it is a really poor year for Butterflies in general. Conditions: Very sunny. Temperature: Max 22- Min 13C.

Holly Blue- female

Holly Blue- female

Holly Blue

Holly Blue on Snowberry

Holly Blue

Holly Blue