by Carmel Rickard
DROWNING is a major cause of unnatural deaths in birds of prey. One of South Africa’s top bird specialists, Mark Anderson, says that a bird of prey with waterlogged feathers has little chance of getting out of a farm reservoir, especially if the dam is only partly full, because it cannot scramble up the sheer sides and it cannot fly up from the water if its feathers are too wet.
Once the bird dies its carcass stays in the water, polluting it so that neither humans nor livestock can drink it. It’s obviously a great waste of water when the whole dam must be emptied and cleaned.
According to official records 322 raptors of 29 species have drowned in farm reservoirs in South Africa – but obviously these are only the deaths that are officially logged and Anderson speculates that hundreds die every year.
Experts have so far put forwards three theories for why raptors drown in farm reservoirs. They may accidentally slip into the reservoir while they are perched on the wall to drink. They may also fall in if they are unable to judge the depth of the water and then try to stand in the reservoir, thinking it is the shallows of a river or an earth dam.
The third theory is that raptors and vultures that may have eaten poison of the sort that makes them very thirsty (like strychnine), may have simply plunged into any available water to slake their thirst. When the bird starts to drown and thrashes around it could attract others to what seems like a feeding frenzy.
How can these drownings be prevented? Anderson says the solutions are simple. First, keep reservoirs full. Second, keep reservoirs covered with shade cloth or other material – this will have another spin-off in reducing evaporation and the growth of algae. Third, attach a wooden plank, log, ladder or branch firmly to the side of the reservoir, and let the length project outwards. “A drowning bird will then be able to grasp onto the wood and lift itself out of the water.”
If you need any further information about this issue, please contact me – 082 551 3293 – so that I can put you in touch with Anderson.
