Of course in my “line of work” the books I know and recommend are mostly out of print, but these are fabulous:
Books by:
Robert McClung (I’ve had a couple of families join my library just to have access to these – some are for olders…look for titles such as Ruby Throat, Bubo, Stripe, etc.)
Gladys Conklin (I bet I read I Caught a Lizard to my son 100 times)
Alice Goudey ( Here Come the… series, wonderful! And I second the Day We Saw the Sun Come Up…I love that book!))
Millicent Selsam (she wrote for olders, too)
The Step Up series – ____ Do the Strangest Things (Insects, Birds, Reptiles, Fish, etc.)
Let’s-Read-and-Find-Out – many of these are in print. Illustrations redone but the text is the same. These are very good for this age group written on many topics. Ex. Germs Make Me Sick, Fireflies in the Night, How Many Teeth, Straight Hair, Curly Hair, etc.