Response to Colour in Birds

Abstract

APART from some experiments by Marples¹, little work appears to have been done on the colour awareness of birds in their wild state. By colour awareness is meant the ability to detect and react to light of widely differing wave-lengths. The possibility that such recognition may, in birds, involve merely the detection of different intensities of a single shade has not been overlooked, but is contra-indicated by the experiments described here. These experiments have been carried out by utilizing the instinct of nest-sanitation whereby most birds, and especially those of the Passerine order, keep their nests free from contamination by the excrement of the young. This instinct has been shown by Smith² to be of the same order of strength as that to feed the young, and the provision at the nest of artificial fæces of various colours gave a ready means of testing the response to colour in certain species. These artificial fæces were made from 'Plasticine' moulded into the shape and size of a fæcal sac, and spectroscopic analysis of the samples employed gave the data shown in