Great season for Wattled Cranes

The 2011 Wattled Crane breeding season has been a bumper season thus far!  We have managed to complete two aerial surveys, thanks to Ezemvelo KZN

A pair of Wattled Cranes stand near their nest during the aerial surveys

 Wildlife and The Bateleurs, to record the breeding status of the known breeding pairs in the province.

This has helped facilitate the successful collection of 6 abandoned ‘second eggs’, of which all have hatched and are doing well under the care of Johannesburg Zoo.  Wattled Crane pairs may lay two eggs, however only they only ever hatch and raise one chick, thereby leaving the second egg to die.  As a partner in the Wattled Crane Recovery Programme, the EWT is responsible for the second egg collections and, in the future, post-release monitoring of birds released back into the wild. When a nest with two eggs is located then I visit the nest to measure and weigh the eggs in order to determine a hatch date for each egg, the nest is then revisited on the hatch date of the first egg, so that the second egg can be collected once the first egg has hatched. 

Weighing and measuring of the eggs allows us to determine an estimated hatch date

 

A newly hatched Wattled Crane chick

 All six of the chicks are doing very well and are walking several hours a day…keeping both themselves and their handlers very fit!

In conjunction to the egg collections we have caught and colour ringed three Wattled Crane chicks.  Each bird has been fitted with a unique colour combination of rings and will serve as their ‘I.D book’ for the rest of their lives.  The colour ringing gives us valuable infomation about the population including movement, longevity, age-specific mortality, age of first breeding and ‘partnerships’. 

 

A 14 week old Wattled Crane chick is released after it was fitted with colour rings

 Obviously, Wattled Cranes are heavily dependent on wetlands for breeding, and even more specifically they require open water within these wetlands to build their nests.  It is therefore vitally important that we work tirelessly to conserve or rehabilitate this scarce commodity.  We therefore work very closely with the Mondi Wetlands Programme, Working for Wetlands, and the KZN Biodiversity Stewardship Programme to achieve this.  We are in the process of completing ‘Wet-health’ assessments on currently and historically breeding wetlands.  The photo below is the team conducting a ‘Wet-health’ assessment….even in weather conditions only suitable for sitting on a couch and drinking hot chocolate.   

Completing the field component of a ‘Wet-Health’ assessment, that looks at the health and functioning of a wetland and it’s catchment

Until we meet again… hope you enjoyed the read!

 

 
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4 Responses to Great season for Wattled Cranes

  1. An interesting and informative read, Tanya with great photos. Well done as I know much of the monitoring and collecting of eggs takes place in very cold wintry conditions and much coordination goes into getting them safely up to Johannesburg Zoo. Strength to all those who are now feeding them around the clock! It is great that you emphasize how important it is conserve and rehabilitate wetlands for these special birds and other species.

  2. tanyacsmith says:

    Hi Donella, thanks for the comment. Yes the work is often in cold conditions…but it’s so worth it! I do feel for the Jhb staff as they have to feed the chicks every 2 hrs around the clock for the first 2 weeks of their lives…hectic committment! The habitat, breeding pairs are dependent on is vital to ensure the persistance of the population, so I often have mud ‘between my toes’!

    Hope all’s well!

  3. Hi Tanya,
    How do you determine the hatch date by measuring the size and the weight of a fertile egg?
    Great work. Congratulations.
    George Archibald, (George@savingcranes.org).

  4. tanyacsmith says:

    Hi George, without putting the formula and graph online…we basically use the length and breadth to get a measure of volume of the egg. The volume and the weight of the egg can give us the density of the egg. We then have a graph of ‘no. of days incubated’ on the x-axis and ‘density’ on the y-axis. We then plot the eggs densities onto the graph and we know how many days each egg has been incubated for. This allows me to go back to the nest when the first egg is hatching or has hatched and collect the second egg, that normally would perish. All of this is in our breeding site monitoring protocol, if you interested in seeing the graph and formula’s.

    I hope you are well!

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