In the UK people talk of "cabbage white butterflies". Whereas there are two distinct species. The small white (Pieris rapae) and large white (Pieris brassicae). There also reports of the Southern small white (Pieris mannii) which is extending its range northwards.
Unfortunately the Green veined White (Pieris napi) and females of the Orange tip butterfly (Anthocharis cardamines) are confused with so-called "cabbage white". Even the "cabbage whites"won't necessarily lay eggs on commercial brassica crops. They also lay eggs on wild flowers of the brassica family.
Bugs and Birds aren't my thing, but I must say that you folks are posting some spectacular stuff. Not only are the photos first rate, but the information ya'll provide along with them have been an education. Thanks for doing this, and keep them coming.