Scribbleyjack eggs. The name scribbleyjack maybe a local name and I've known it since I understood words. It's easy to understand why its called a scribbleyjack by the patterns on the eggs.
I found many nests when I was a youth, sadly there are not many to find now. When farming practices altered and the stubble was ploughed in and sown before winter the birds couldn't glean the stubbles over winter so starved. Many other birds suffered because of the autumn sowing including Linnets and Skylarks.