Savannah Sparrow (Passerculus sandwichensis) Science Article 1
abstract
The orientation system of the Savannah sparrow (Passerculus sandwichensis) is typical of nocturnal migrant passerine birds. It is based on a system of interacting compass senses: magnetic, star, polarized light and, perhaps, sun compasses. The magnetic compass capability develops in birds that have never seen the sky, but the preferred direction of magnetic orientation may be calibrated by celestial rotation
KENNETH P. ABLE AND MARY A. ABLE, The Journal of Experimental Biology 199, 3-8 (1996)