Hi Bob
I may be way off the mark but it sounds a bit like Lapwings. Do you get them in your field or see them around?
I found this alarm call of a flock which were disturbed by a fox.
Play this audio clip
Gunnar Fernqvist, XC220976. Accessible at www.xeno-canto.org/220976.
If it is Lapwings I'm not sure why they would be calling after dark unless disturbed perhaps by the dog.
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Tony
My Flickr Photostream
Here's the thing, I never see them, they only start when it's dark and they're in an empty field next door to the house. To be honest, that Lapwing doesn't sound the same. I've a few more calls recorded which I can also upload. Never hear them during the day, but at night for the last few weeks it's every night without fail.
Upload them by all means, someone may have a better idea than me. Also, it's a good idea to give more information about the habitat and where in the country you are located.
Here's some more, though they only really go big around the 40 seconds mark http://chirb.it/C3Dqk0 Located in NW Northern Ireland along the Derry/Donegal border.