Monday, 1 February 2010

2009 - A summary

In early April 2009 I collared 10 zebra mares within the Makgadikgadi Pans National Park so that I would be able to follow the movements of these zebra throughout the year. Due to regular rainfall throughout the year, 2009 has been an eventful and prosperous year for the Makgadikgadi zebra. The zebra have been able to remain in the open grasslands of the Makgadikgadi to feed on grass which has not stopped growing all year. All of this has meant that the zebra foals born during the 2008-09 wet season have had a great chance to survive their first year of life – typically the hardest for any animal.

During the 8 months since the collars were deployed, 1 collared zebra was killed and eaten by lions in July and 2 of the remaining 9 GPS collars failed due to technical problems. Despite the problems I have been able to collect over 150,000 GPS positions from the 10 collared zebra thus allowing me to view up-to-date movements in response to rainfall, the drying up of waterholes and grass availability.

The fieldwork I have conducted during 2009 has been an incredible learning experience for me with a lot of valuable data collected. Since deploying the collars I have studied the grass that the zebra choose to eat and the waterholes where they prefer to drink. I have also observed the behaviour of zebra by conducting sunrise to sunset observations with additional observations of their grazing behaviour. Samples of grass, water and faeces have been collected for more detailed analysis later so that I can study how the zebra are making the most of limited water availability. During 2010 I will look to build on the data collected in 2009 as well as collecting other types of data to help answer my questions.

When you use GPS collars to track wildlife one of the most important decisions is to decide how long you want to collect data for. There are two main options – a long collar life with less GPS fixes taken daily or a short collar life with a high-intensity of GPS fixes taken daily. Both options have their merits depending on the data that you are looking to collect. I chose the latter knowing that I would have to remove the collars before the end of 2009 to refurbish them with new batteries. Therefore, at the beginning of December, with the assistance of a qualified veterinarian, I set about trying to remove the GPS collars.

Usually when you are darting wild animals, particularly to remove or replace collars, the hardest part is finding your target animal. However, in this instance, finding the collared zebra was the easy part, the hard part was getting close enough so that we could dart them. After a couple of frustrating days when we were unable to get close to any of the collared zebra we realised that our best chance would be in the hours immediately after sunrise when the temperatures were still bearable and the zebra were more relaxed. This meant we needed to be up by 4am so that we could be with a collared zebra before sunrise. Our new strategy paid off immediately as on the third morning we were able to remove the collars of 2 zebra before 8am.

Over a period of 8 days we were able to successfully remove the 7 working GPS collars. I removed 1 of the faulty collars in July and this means that the one collar which remains is one which failed in September. I will try again to remove this collar in March 2010. During the darting we were also able to collect some important information on the weights and physical condition of the collared zebra that were all heavily pregnant and due to give birth imminently.

The data provided by the GPS collars is vital in helping me to understand how zebra are able to survive and thrive in the challenging Makgadikgadi environment. Not only do the collars provide detailed movement data, they also allow me to track the zebra so that I can study behaviour as well as identify and sample the grazing and water resources which they are utilising. It is for this reason that in March 2010, once my collars have been refurbished, I will collar a further 10 zebra mares so that I can follow their movements within the Makgadikgadi throughout 2010.

During the darting period, whilst tracking a collared zebra, we were lucky enough to come across a mare just about to give birth so we stopped to observe this special event. Within 15 minutes the foal was up on its feet before its mother, looking a little wobbly at first but soon gaining confidence in how to use all 4 limbs in unison. The rest of the harem were not far away and soon came to greet the new arrival, a yearling was particularly interested, before they all moved off to rejoin the safety of the herd. The first few days of this foal’s life will be the toughest but if it can stay close to its mother then it will have a great chance of reaching adulthood due to the abundance of water and grass available this year.

If you have any questions or comments then please feel free to email me, or visit the project website where there will be additional photos and blogs added shortly.

Best wishes for a healthy and prosperous 2010.