scansores

from The Century Dictionary.

• The climbers or scansorial birds, an old artificial order of birds, corresponding to the Grimpeurs of Cuvier, having the toes in pairs, two before and two behind (see cut under pair-toed), whence also called Zygodactylæ.
• Applied by Sundevall to sundry other groups of climbing or creeping birds, as creepers, nuthatches, etc., usually placed in a different order: same as Certhiomorphæ.

from the GNU version of the Collaborative International Dictionary of English.

• noun plural (Zoöl.) An artifical group of birds formerly regarded as an order. They are distributed among several orders by modern ornithologists.