MISSION 29 of 2012

Name of Mission: Hippo Count at iSimangaliso
Date of Mission: 26 November 2012
Aircraft used: Cessna 182
Pilot: Chris Rattray
Beneficiary: Alexa Prinsloo, University of Cape Town

 Objective of the flight

The objective of the flight was to fly over all the major water bodies within the iSimangaliso Wetland Park, counting and recording the GPS position of all hippopotamus groups or lone individuals observed, to determine the total minimum number of hippos in the system. The GPS positions will be used to determine the spatial distribution of hippos.

Pilot’s Report by Chris Rattray

“Alexa Prinsloo, a Masters student of Zoology at the University of Cape Town, needed to count the hippos in the Greater iSimangaliso Park, i.e. from St Lucia Estuary (mouth) to Kosi Bay (mouth), including all the water, channels and lakes in between, including Sibaya and Bhangazi.

The flight was conducted with a GPS marker – Alexa – and two counters – Dan Groves and Lawrence Beith – on a clear day with minimal turbulence and good visibility. The count was conducted at 300 ft, circling larger pods of hippos which were easily identified.

Alexa will produce a detailed report including the distribution and numbers of hippos seen on the day.”

Beneficiary’s Report by Alexa Prinsloo

“Initially the flight was scheduled for Sunday 25th of November 2012, but it had to be cancelled due to bad weather. Thankfully our pilot, Chris Rattray, was kind enough to make himself available for a flight the very next day. Isimangaliso Wetland Park Authority was truly accommodating in obtaining clearance for the flight on the 26th of November 2012. So with everything coming together and the weather playing along, we were finally able to get a bird’s eye view of the entire system, which is a truly invaluable perspective for a researcher.

The flight was an absolute delight. We flew with Chris Rattray in what was definitely the smallest plane I’ve ever flown in, a Cessna 182. We took off from the Monzi airfield and flew towards the mouth of the St Lucia Estuary, which was closed. The very first group of hippos was observed at the mouth. We flew up along the Narrows counting and recording the position of all observed groups or individuals. From there we flew along the western shores of all large bodies of water, up to the northern edge of iSimangaliso Wetland Park, near Kosi Bay. We then headed back down along the eastern shores of those same water bodies. Upon our return to Monzi airfield we had a smooth landing and a quick photo shoot to commemorate the experience.

Smaller pans extending throughout the wetland - by Alexa Simone PrinslooAltogether we counted a total of 379 hippos. This is less than 50 % of the population as reported in the annual count conducted by iSimangaliso and Ezemvelo for May 2012. This discrepancy may be explained by the increase in rainfall throughout the system, resulting in more small pans forming, allowing hippos to move into areas where the density of vegetation reduced visibility. The area covered by water was also too extensive to cover during one flight, using the current method, thus we did not fly over all water bodies. The majority (66%) of hippos observed were in the Narrows, suggesting that there are habitat variables within this region which makes it more suitable for hippo habitation. My project hopes to determine what these habitat variables are.”

Conclusion: Was the objective met?

“Overall it was a very successful mission. We met the objectives which were to count and record the location of hippos within the major water bodies within iSimangaliso Wetland Park. The discrepancy between our total minimum count and that of the annual count from May 2012 is not of consequence as our object was not to determine the total population, but to determine the coarse spatial distribution of hippos within the system.

I would like to take this opportunity to thank The Bateleurs and Chris Rattray for flying this mission. The data collected will add to our understanding of hippo spatial distribution and habitat requirements, all of which are invaluable in informing conservation decisions.”