Alabama – Yellowhammer State.

Alabama has been known as the “Yellowhammer State” since the Civil War. The yellowhammer nickname was applied to the Confederate soldiers from Alabama when a company of young cavalry soldiers from Huntsville, under the command of Rev. D.C. Kelly, arrived at Hopkinsville, KY, where Gen. Forrest’s troops were stationed. The officers and men of the Huntsville company wore fine, new uniforms, whereas the soldiers who had long been on the battlefields were dressed in faded, worn uniforms. On the sleeves, collars and coattails of the new calvary troop were bits of brilliant yellow cloth. As the company rode past Company A , Will Arnett cried out in greeting “Yellowhammer, Yellowhammer, flicker, flicker!” The greeting brought a roar of laughter from the men and from that moment the Huntsville soldiers were spoken of as the “yellowhammer company.” The term quickly spread throughout the Confederate Army and all Alabama troops were referred to unofficially as the “Yellowhammers.”
source: http://www.archives.state.al.us/emblems/st_bird.html