Are songbirds really same level as old Kipper type books?

[Tiggles]

Didn't think I would ever ask a question about reading on here as I am very pleased with the way DS is doing at his reading and how his school are teaching him. But just curious really.

When he gets Biff and Kipper type books (standard ORT?) they seem much harder to read than the Songbirds at the equivalent level, i.e. he can read the Songbirds without stumbling on a single word as the phonics are so much simpler. So is a level 2/3/4 ORT for the same age as a level 2/3/4 songbird etc. or are the level 2/3/4 songbirds easier?

No, the songbirds are phonics books, which means all the words within are decodable to anyone who is learning phonics ( which in theory most schools should be!) The old Kipper books are look and say, which means there are lots of words in there he can't yet decode and has to be told or helped with. So whilst in theory they are meant to be the same level, in practice they are not!
Have a look at www.oxfordreadingtree.com/chart/

Biff Chip and friends are harder for the child to read because they contain words which the children haven't got the skills to read ...yet! Which is why adults need to either tell them the word or tell them to work out what it might be by looking at the illustrations but having said that the books are technically the same reading level.