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   
Emu
http://www.birdlife.org.au
  A Journal of BirdLife Australia
 
blank image Search
 
blank image blank image
blank image
 
  Advanced Search
   

Journal Home
About the Journal
Editorial Board
Contacts
Content
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 107(4)

Reproductive activity in the Osprey (Pandion haliaetus) on Kangaroo Island, South Australia

T. E. Dennis

5 Bell Court, Encounter Bay, SA 5211, Australia. Email: osprey84@internode.on.net
 
PDF (198 KB) $25
 Export Citation
 Print
  


Abstract

This study reports on aspects of the breeding biology of Ospreys (Pandion haliaetus) on Kangaroo Island from data collected over 18 breeding seasons between 1985 and 2004. Over this period an average of nine pairs were located each year, and a total of 145 occupied territory years were monitored for breeding activity and outcomes. Of these, active breeding occurred in 103 (71%), with 60% of these successfully fledging young. Productivity was found to average 0.66 young fledged per year per occupied territory, and 0.92 young fledged per year per active nest. This level of productivity, while similar to that of other studies in Australia, is below the minimum recruitment levels needed to maintain migratory Osprey populations in the northern hemisphere. However, such high rates may not be needed in the non- migratory population of Australia. Although some early dispersal was recorded among marked Osprey young, strong philopatric recruitment was also evident, with 22% of survivors either remaining on the island, or returning at maturity to join the breeding population. Through the re-identification of individuals, Osprey pairs were found to remain together over many seasons and to use the same primary nesting site. The breeding season began later than reported elsewhere in Australia, extending from August to February, with most laying occurring in September. Undetected nest predation and human disturbance was suspected at accessible nests as contributing to the high level of nest failures recorded. The apparent elongated nestling development period found is comparable to that determined in other studies where fluctuating prey availability directly influenced nestling growth and survival. These factors, plus geographical isolation, suggest the Osprey may be precariously balanced ecologically at the southern extent of its breeding range in Australia.

Keywords: disturbance, eye character recognition, low productivity, nest failure, nest predation, pair fidelity, reproductive outcomes.


   
Subscriber Login
Username:
Password:  

    
Legal & Privacy | Contact Us | Help

CSIRO

© CSIRO 1996-2014