SPECTRAL PECKING PREFERENCE IN GULL CHICKS - POSSIBLE RESOLUTION OF A SPECIES DIFFERENCE

Determined the spectral response curve or pecking rate as a function of spectral position of 10 newly hatched dark-reared unfed laughing gull chicks (Larus atricilla) for randomly ordered stimuli in the visible spectrum. Results with wide-band Wratten filters, uncontrolled intensity relationships, and a tungsten source show a single peak in the red consistent with results from Kear on L. argentatus and L. fuscus. However, previous experiments with L. atricilla using narrow-band stimuli of equal quantum intensity and approximate equal luminosity have resulted in a bimodal response curve with a major peak in the red-orange and a minor peak in the blue. Stimulus band width and intensity are thus implicated as important variables controlling the behavior. (PsycINFO Database Record (c) 2006 APA, all rights reserved). © 1969 American Psychological Association.