Clutch size and egg characteristics of Cotton Pygmy-Goose in Assam (India)

The reproductive output of the waterfowl depends on the nutrients present in the eggs. The average clutch of each species of waterfowl has been evolved in relation to the average availability of food for the female around the time of laying, modified by the relative size of the egg. It has been also suggested that the species laying eggs that were small, relative to their body size, would be able to lay many eggs, whereas species laying large eggs would lay fewer eggs. The Cotton Pygmy-goose eggs were light creamy white or light ivory white in colour on the day of laying with the mean size of 13.94 +0.4 SD. The overall clutch size found was 14.2. The mean size of the eggs ranges between 13.50 to 14.76 cm2 (mean= 13.94 +0.4 SD). The overall mean length of the egg was found to be 42.8 mm +0.7 SD (range 42.0 – 44.6 mm, n=21), whereas the mean egg width was 32.4 mm +0.5 SD (range =31.5 – 33.1 mm, n=21). A strong positive and significant relationship exists between egg length and width (r= 0.8 & p= 0.0001). The mean weight of the eggs was found to be 25.006 +0.2 SD (range: 24.5 to 25.75 gm). Standard methodology was followed to execute the study. The present paper deals with the study of clutch size and various characteristics of eggs of the species in concern and their relation with the female.