Projects of the Animal Demography Unit

Colour-ringing of colonial waterbirds on the Cape peninsula

Where do juveniles go after fledging?

Doug Harebottle
Animal Demography Unit
Sacred Ibis colony at Rondevlei
Photo Doug Harebottle
A nursery of African Sacred Ibis chicks at Rondevlei Nature Reserve with an individually colour ringed bird, November 2005

How far do juvenile waterbirds disperse after breeding? Do they return to their birthplace to breed? Do they move around between different wetland sites on a regular basis? These and other fascinating questions about how certain waterbirds use wetlands will hopefully be answered through a colour-ringing study of colonial waterbirds that got underway this breeding season (2002) at various localities in and around the Cape peninsula.

Initiated as part of CWAC and SAFRING projects, this study will focus largely on Sacred Ibis and Cattle Egret, two species' whose size and colonial breeding habits make them perfect candidates for such a study. However, other colonial breeders (inc. spoonbill, herons and night-herons) will also be targeted, where possible.

In keeping with the projects's objectives, pre-fledging birds will be the main focus of the ringing component of this study. Adult waterbirds are generally very difficult to catch, but as juveniles remain flightless until fledging, they are easier to catch and ring. In addition, juvenile Sacred Ibis form relatively large nurseries once they leave the nest, and this allows for large numbers (up to 100 birds) to be caught and ringed during a single ringing session.

All birds caught will be fitted with, at least, a SAFRING metal ring and a single site-colour ring. The colour-rings will be specific to a locality so that we can identify where the bird was originally ringed, while the position of the metal and site colour-ring on the legs will indicate the year or season in which they were ringed. Some birds will also be individually colour-marked using additional colour rings. The ring codes and colour-cominations for each year are given below.

Year Basic SITE CODE Unique colour-combinations Example
2002 METAL on right tarsus
COLOUR on left tarsus.
None
2003 METAL on left tarsus
COLOUR on right tarsus
Additional colours placed above site colour, above metal ring or on left/right tibia.
2004 METAL on right tibia
COLOUR on left tibia
Additional colours placed above site colour, above metal ring or on left/right tarsus.
2005 METAL on left tibia
COLOUR on right tibia
Additional colours placed above site colour, above metal ring or on left/right tarsus.
2006 METAL on right tarsus
COLOUR on right tibia
Additional colours placed above site colour, above metal ring or on left/right tarsus.

Also individually colour-coded rings.
2007 METAL on left tarsus
COLOUR on left tibia
Additional colours placed above site colour, above metal ring or on left/right tarsus.

Also individually colour-coded rings.

The colour rings used for individual sites include the following:

Rondevlei Nature Reserve Red
Paarl Bird Sanctuary Yellow
Robben Island Green
Zeekoeivlei Blue
Intaka Island White
Progress

Click on a link to get an update and summary of birds ringed to date:

How you can help...

You can make an important contribution to this study by becoming a RingWatcher. Launched as part of the Hartlaub's Gull colour-ringing project in 2000, ring-watching will add more excitement to your birding each time you visit a wetland.

To ring-watch all you have to do is be on the lookout in the coming months (and years) for any of the birds that have been colour-ringed at Rondevlei, Paarl Bird Sanctuary and/or Robben Island. If you do see any of the above species with a red, yellow or green ring please report your sighting to SAFRING as soon as possible and include the following information:

All ringwatchers reporting re-sightings will be acknowledged.

Should you know of other localities with large, active heronries please contact Doug.

Acknowledgements

This project has been funded in part by the National Research Foundation, Rondevlei Nature Reserve and the Tygerberg Bird Club

Any queries or questions can be directed to Doug Harebottle
email: doug.harebottle@uct.ac.za    Tel: (021) 650-2330   Fax: (021) 650-3434