What is "brush bird"

Scrub \Scrub\ (skr[u^]b), n.

1. One who labors hard and lives meanly; a mean fellow. ``A sorry scrub.''
   --Bunyan.

   We should go there in as proper a manner as possible; nor altogether like the scrubs about us.
   --Goldsmith.

2. Something small and mean.

3. A worn-out brush.
   --Ainsworth.

4. A thicket or jungle, often specified by the name of the prevailing plant; as, oak scrub, palmetto scrub, etc.

5. (Stock Breeding) One of the common live stock of a region of no particular breed or not of pure breed, esp. when inferior in size, etc. [U.S.]

6. Vegetation of inferior quality, though sometimes thick and impenetrable, growing in poor soil or in sand; also, brush; -- called also scrub brush. See Brush, above.

7. (Forestry) A low, straggling tree of inferior quality.

   Scrub bird (Zo["o]l.), an Australian passerine bird of the family Atrichornithid[ae], as Atrichia clamosa; -- called also brush bird.

   Scrub oak (Bot.), the popular name of several dwarfish species of oak. The scrub oak of New England and the Middle States is Quercus ilicifolia, a scraggy shrub; that of the Southern States is a small tree ( Q. Catesb[ae]i); that of the Rocky Mountain region is Q. undulata, var. Gambelii.

   Scrub robin (Zo["o]l.), an Australian singing bird of the genus Drymodes.