Hi there, I was walking around today when I noticed an odd sound from a bush, I though it was a quiet frog squeal at first, but then noticed it was coming from the leaves.
As I move around I noticed hoverflies (Syrphus or a lookalike) that were flying around and sitting down on the leaves, and when they sat down they made an odd sort of ‘weeeeeeeeeh’ sound till they flew off.
Best way to describe it is like the sound from slowly letting the air out of a balloon.
Couldn’t get pics or sound clips as the dog had gotten bored and carried on without me so I had to go catch up.
Do you kind of know what species of hoverfly they were? Where do you live? The location can also be helpful.
My best guess is a Syrphus, black/yellow striped body but lanky rather than round.
I’m in the East Midlands and was in a wooded area near a local nature reserve.
So, was this sound any different from their wing sound in flight?
Yeah, it wasn’t a buzz of any kind that I’ve heard before, like I said my first though was a frog squealing. It was like listening to a bush full of balloons letting air out slowly, - just more quiet.
Here they state they can make sounds
Spilomyia also makes a high-pitched buzzing sound if disturbed, hypothesized to be an attempt to sound, as well as look, like a wasp.
The distinct high-pitched acoustic response to attack had a significantly higher mean fundamental frequency compared with the fundamental frequency of the same individual’s sounds recorded during flight. High-speed imaging revealed that during this sound production period, wings were held almost parallel to the longitudinal axis of the body and thoracic segments appeared to be vibrating.
Were their wings still moving when this sound was made? I wonder if the leaves were amplifying the vibration like a sounding board - or perhaps an effect of the downdraft of the wings on the leaves. If by ‘lanky’ you mean long-bodied then Sphaerophoria is perhaps an option. (Syrphus itself though fits the behaviour better, and they are quite buzzy)
They did not appear to be moving their wings, and they only did the sound when sitting on the leaves. They also tended to fly off if I got too close so couldn’t get a proper look.
Next time I wander through an East Midlands LNR I shall pay attention to the wheezing Syrphines! Perhaps they’re still recovering from the epic heat…! (I did get a picture of a Syrphus that was flying at 39-point-something °C on Tuesday - not uploaded yet)
Have you checked the article I linked? Was their wing position similar to that?
It’s possible, but I honestly don’t remember clearly enough. I don’t remember them ‘t-posing’ with their wings in any case.
Sort of regretting not taking my phone out for photos/vids because I was just too busy trying to figure out what I was hearing…
This is why Steven Falk calls Syrphus ribesii “Humming Syrphs”.
“the main hoverfly responsible for the mysterious hum that you sometimes hear in a wood (created by thousands of males vibrating their wings as they rest on tree foliage)”
( from Falk’s Flickr )
There are other hovers in the UK which have a notable buzz, but Syrphus are the most common and one of the loudest / most distinctive - of the ones I come across in Shropshire at least.
I found the culprit, didn’t get any sound but caught a pic this time: https://uk.inaturalist.org/observations/128001844
The pic was taken as it was making the sound, it took off and flew around my head a few times, at which point there was normal buzzing sounds as expected, but whenever it landed it made that same whine. (it was also very suspicious of me so I only got that single pic)
Interestingly enough I heard a similar sound, but much lower in volume in the same area, and I found it was coming from a Marmalade Hover Fly (Episyrphus balteatus) - Which flew away before I could take pics.
Now that I’ve heard it a couple of times I find that specific area has a fair bit of that quiet whining noise.
I’m sitting with a syrph now and now too can see where the sound comes from, when sitting it vibrates first pair of wings, so from afar they seem to be in one place, but actually are going fast at small amplitude.
Aye, that is indeed a male Syrphus sp.