Monthly population changes of Common Teal Anas crecca in a regulated pond in the C district of Morinosato (Atsugi City)

Abstract

We carried out observation of the Common Teal Anas crecca at the C area regulatory pond in Aoyama, Morinosato, Atsugi with the following results:

1)The ducks observed, with the exception of 2015-2016, was about 100± with a peak seen in February. This is a higher population than other fixed linear surveys reported in the Kanagawa area.

2)During the day the Common Teal mostly rest or sleep at the C regulatory pond and at night move to their foraging grounds. Movement occurs during the dark hours after sunset and before sunrise. The ducks movements correspond to the periods of earlier and later sunrise /sunset times. They moved in groups of a few ducks to 10 or more.

3) Movement to their resting/sleeping areas are dependent upon the movement of the sunlight.

4) There was a large difference in the number of observed duck populations each day.

5) After eclipse molt is finished in January (to easier identify) the male/female ratio was calculated. There were slightly more male than female with a ratio of roughly 1:1.