Mystery noise - sonic repeller?

[moorfield]

There is a mystery noise we have been hearing outside Moorfield Towers for the last few months that is starting to drive me nuts, if only because I want to understand what it might be. It sounds like a bird call - a collared dove or owl perhaps - but I think is artificial.

Observations so far:
- can been heard irregularly/intermittently at different times of day (mornings, mostly afternoons, and late at night)
- always eight (8) "coos" of same (lowish) pitch, a duration about 2-3 seconds in all - yes I have counted (hence why I think is artificial)
- always from same direction, perhaps from a next-but-one neighbour's property

Lady M describes it sounding like a child's toy eg. "ray gun" - we have ruled that out because we hear it late at night.
There is a small business (funeral people) a few doors down - thought it might be reversing vehicle noise but have also ruled that out.

I can only think it must be some garden gadget somewhere, perhaps some kind of repeller. But a repeller of what, and how activated?

Any thoughts suggestions etc., appreciated.

[moorfield]

- always eight (8) "coos" of same (lowish) pitch, a duration about 2-3 seconds in all - yes I have counted (hence why I think is artificial)

Edit: 4-5 seconds

[mc2fool]

I can only think it must be some garden gadget somewhere, perhaps some kind of repeller. But a repeller of what, and how activated?

Animal repellents (motion detector activated) are all ultrasonic ... and teenager repellents can't be heard by anyone past their early 20s ...

[Mike4]

Is it an artificial noise made by a vehicle reversing, perhaps? An electric vehicle?

Trouble is, questions like this usually result in a thread filling up with wild guesses like mine, all vaguely credible but with little hope of being verified, like mine above.

I think I'd try to track it down by trying roughly to determine which direction it comes from, them asking the neighbours in that direction if they too have noticed it and have any thoughts...

[moorfield]

Trouble is, questions like this usually result in a thread filling up with wild guesses like mine, all vaguely credible but with little hope of being verified, like mine above.

Yes it's a tricky one, if I knew what to Google (I don't) no doubt I'd find something, in that respect even guesses might give me something to work on. The fact it is always 8 low pitch "coos" I hoped someone might recognize ...

[servodude]

Trouble is, questions like this usually result in a thread filling up with wild guesses like mine, all vaguely credible but with little hope of being verified, like mine above.

Yes it's a tricky one, if I knew what to Google (I don't) no doubt I'd find something, in that respect even guesses might give me something to work on. The fact it is always 8 low pitch "coos" I hoped someone might recognize ...

try googling for the call of a short eared owl..
actually here's one https://www.youtube.com/watch?v=FL5Cl6A_1mo
- pretty sure they're found over most of Europe

my first thought for artificial sounding "owl" was a Tawny Frogmouth but you ain't got those https://www.youtube.com/watch?v=Ohu9mPFMXEk

- sd

[moorfield]

try googling for the call of a short eared owl..
actually here's one https://www.youtube.com/watch?v=FL5Cl6A_1mo
- pretty sure they're found over most of Europe

No not that. I think it is an audible bird scarer on an infrared sensor, that's my best guess. Maybe to keep the sh*****g pigeons away.

[madhatter]

No not that. I think it is an audible bird scarer on an infrared sensor, that's my best guess. Maybe to keep the sh*****g pigeons away.
Top

Last year, on a bird watching walk nearby, I was emerging from a patch of woods and detected a “bird noise”.

Actually it was more of a “WTF is that”, noise.

I’ve been trying to learn bird sounds only for the last few years and still have a long way to go, including a book about “Birdwatching with your eyes closed and the RSPB book about British Bird Song, plus several apps that include songs and calls, but this was loud, coming from a house, and didn’t sound like any of the ones I had listened to in practice.

Eventually emerging, blinking into the open there was a oversized owl, fixed to a chimney stack, which seemed to be keeping very still, and was being totally ignored by pigeons, squabbling crows and magpies passing joggers and dog walkers etc.

My eyesight is not good, but bringing binoculars into play showed it to be a model, not particularly convincing, and the sounds seemed to be emanating from the same direction. Not sure what the sound was meant to be. Too much twittering for the owls in the recordings. Perhaps some generic bird in distress?

Whatever, I have since passed the same place several times and while the “owl” is a fixture, it was mostly switched off.

It was not clear if the sound was coming from the model itself or a separate source nearby. Perhaps it would have worked if it had only been used in short bursts of seconds to minutes?

While it was on, it was certainly loud enough and almost continuous and would have quickly got right up my hooter had I lived nearby. If the object was to deter pigeons etc, it was also an epic fail.

[bungeejumper]

No not that. I think it is an audible bird scarer on an infrared sensor, that's my best guess. Maybe to keep the sh*****g pigeons away.

Well it won't be a collared dove sound, then. Having battled for years against some very pesky urban pigeons at our rental property, and having tried everything - including a sonic repeller - we learned something we should have known all along.

Namely, that pigeons and their ilk don't have a distress call, so there's no point in trying to reproduce one. And that the reason pigeons are so hard to shift is that they are too intelligent to be fooled by these sorts of tricks. In fact, the only thing that I can imagine resulting from a repeller is that foxes might turn up in the hope of an easy meal.

We finally solved our urban pigeon problem, though. Partly with netting, which persuaded them to pick on somebody else rather than us. And partly because the council finally got round to prosecuting the crazy old woman who was feeding them. So now she feeds the seagulls instead. You can't win.

BJ