Quail in my area have declined significantly over the last decade. On my Uncle's farm I used to flush large bevys of over 40-50 birds just a decade ago. The habitat hasn't really changed, but a succession of hard Winters and a drop in fur prices are the most likely culprits. There's quite a few more raccoons, skunks, and possums now, resulting in high nest predation and fewer birds being recruited into the adult breeding population. The same factors have affected pheasant numbers, with the Winters probably being the major factor.
For those really interested in Quail management, I recommend Stoddard's seminal work, "The Bobwhite Quail, It's Habits, Preservation, and Increase". It's long out of print, I managed to find an old library copy around 20 years ago. It's fascinating, and well worth the money for any serious quail enthusiast.
Here's a reprint, pricy, although the least expensive I could find via a brief search.
http://www.abaa.org/book/738730272Here's a downloadable form, I'm not sure if it's the complete book or not.
https://archive.org/details/bobwhitequailits00stodRegards
Ken
