CSIRO Publishing blank image blank image blank image blank imageBooksblank image blank image blank image blank imageJournalsblank image blank image blank image blank imageAbout Usblank image blank image blank image blank imageShopping Cartblank image blank image blank image You are here: Journals > Emu   
  A Journal of BirdLife Australia
blank image Search
blank image blank image
blank image
  Advanced Search

Journal Home
About the Journal
Editorial Board
Online Early
Current Issue
Just Accepted
All Issues
Special Issues
Research Fronts
Rowley Reviews
Sample Issue
For Authors
General Information
Notice to Authors
Submit Article
For Referees
Referee Guidelines
Review an Article
Annual Referee Index
For Subscribers
Subscription Prices
Customer Service
Print Publication Dates

red arrow Complete Archive
blank image
With the complete digital archive of Emu now online, we have selected some of the most interesting and significant papers for readers to access freely.

blue arrow e-Alerts
blank image
Subscribe to our Email Alert or RSS feeds for the latest journal papers.

red arrow Connect with BirdLife
blank image
facebook TwitterIcon LinkedIn

red arrow Connect with CP
blank image
facebook twitter youtube


Article << Previous     |     Next >>   Contents Vol 74(3)

Waking and roosting behaviour of the Indian Myna

J.J. Counsilman

Emu 74(3) 135 - 148
Published: 1974


Waking and roosting of Acridotheres tristis at communal roosts were studied during two years in Auckland. Mynas sleep communally in trees all the year, the only exceptions being incubating and brooding females. Birds use some roosts during late spring and winter only and some roosts throughout the year. The temporary roosts are formed just before reproduction and, when they are formed, numbers of birds visiting year-round roosts drop sharply; they are gradually deserted during the summer long before the end of breeding. At year-round roosts, the times of assembly and of departure show trends relative to civil twilight and are latest and earliest respectively when breeding is at a peak. The intensities of light at which birds arrive and depart are the lowest at this time. These trends are probably because reproductive hormones affect the birds' sensitivity to physical cues or cause an increased attraction to the territory and nest. Throughout the breeding season changes in the status of arriving birds (singles, pairs and groups) correlate with the changing numbers of breeding pairs.

Light is probably the only physical factor that could provide consistent cues to times of waking and roosting. Other factors, such as temperature and humidity, may have an effect, especially on the periods of assembly and departure, An endogenous clock, set by light and possibly a social Zeitgeber, allows early departures, especially important to breeding individuals, it prevents a waste of time and energy during the day that might come from premature roosting.

The time available to breeding birds for feeding and for collecting food for nestlings is increased by leaving early from, and arriving late at, roosts. An early defence of the territory may also advance the time of departure. Vocalizations at roosts do not advertise them but are more proximate socially, as when these calls are given during the day. Gatherings before roosting provide protection from predation, which may be greater in the evening, but do not always prevent foraging. Communal roosting protects Mynas more from predators than if they slept solitarily. Other advantages, such as maintaining the unity of juvenile flocks and an increased efficiency in finding food, come from sleeping communally, but at any one time most birds in Auckland do not exploit these additional benefits.

Full text doi:10.1071/MU974135

© Royal Australian Ornithologists Union 1974

blank image
Subscriber Login

PDF (631 KB) $25
 Export Citation
Legal & Privacy | Contact Us | Help


© CSIRO 1996-2015