Post 380 - The Spectacular, Marvellous and Fantastic St. Marks Fly

St Mark's Fly (Bibio marci) at Ripon

Hey everybody, today's Day 380 and as I haven't covered a species for a while so I thought I'd do one today. I sometimes go out to Ripon and a regular walk we do there is at a nice spot where there's a riverside walk, I see lots of species on the river and in woods. I really love it there and it is a great place to walk about. So when I was looking through my photos and I managed to find something that I saw there. It's called a St Mark's Fly, personally, I didn't know my Dad was a saint, but you learn something new everyday! These were tricky to photograph as they didn't land very often and I had to follow them around for quite a while to get some shots.

Quickly, before I start on the facts, I would like to thank every one of you that brought one of my calenders, using the proceeds my parents managed to surprise me with an Opticron telescope. I'm really happy with it and I hope that I will be able to up my list of birds dramatically with it! Can't wait to test it out at a reserve!

So, here are the facts:

Too difficult that day to photo in flight

• The main reason they are called the St Mark's Fly is because they emerge around the time of St Mark's Day.

• When I say St Mark's Day, it's about the 25th of April, so they are very much a Spring Fly.

• St Mark's Day is a festival held in Italy and is basically a huge feast to commemorate Mark the Evangelist.

• This day is celebrated globally, it seems, even though it celebrates the patron state of Venice. It's celebrated in Lithuania and Mexico.

• It has another name for the people that don't celebrate this event much: The Hawthorn Fly.

• It is 11mm long and has a black and shiny body with quite a lot of hair on it too. 

• They are found on Farmland, Woodland, Heathland, Grassland, Towns and Gardens. So a good variety I'd say.

• They have the conservation status 'common' in both Europe and England it seems.

This one looks a bit different with an antennae
- not sure if it is the same species

• In England they are found mostly in the South of England, like most bugs and Flies, but they get less common the further North you go.

• Swarms of St Mark's flies can be annoying in the early Spring but they are actually quite useful.

• As their main food source is nectar making they are very useful pollinators of fruit trees and crops.

• I must have timed my walk well to see these insects as their adult life cycle only lasts about a week.

You can see here how hairy they are.

• They spend the majority of their lifecycle as larva in the soil where they feed on rotting vegetation.

• Once they emerge as adults, the males emerge first followed by the females, they have a short time to mate and then the female lays eggs in the soil.

• The main habitat for these flies is hedgerows and woodland edges especially if it is a moist area.

Here are some links to some more information:

Buglife - St Mark's Fly

NatureSpot - St Mark's Fly

The Wildlife Trusts - St Mark's Fly

Hope you enjoyed,


Z.