Diminishing Lake Levels Spell Doom for Lake Naivasha
Shiv Kapila— 11 June 2009 — in East Africa Project Share
The second week of my study has passed and things are still running relatively smoothly. I completed the habitat classification of the lake in a day, and managed to conduct another total population count. The lakeshore and its riparian habitat have both been degraded to a severe degree recently due to the rise in numbers of flower farms, local artisanal fishing outposts, cattle dips and increasing human settlements. Some stretches of shoreline are so damaged that they are completely devoid of fish eagles and other predatory birds, waterfowl, and hippos as a result of the disturbance and pollution.
The last two counts of the lake have only yielded an average of about 90 eagles (compared to a count of 150 in January by Munir). This short-term decline, apart from the factor of human encroachment, can mainly be attributed to the lower lake level. The drought in Kenya continues and is on the cusp of becoming a national natural disaster. In combination with the constant draining of the lake by the flower farms, the effect is accelerated here. The lake level has gone down by as much as three feet in the last six months and in some places this means that the shore is now two kilometers away from where it previously was. Favoured fish eagle posts and the nearest vantage points are much further away and the fishing conditions are poorer. The birds are simply struggling to find food. A theory that I’m leaning towards is that the drop in eagles may be because most of them are migrating temporarily to other more permanent and stable watercourses, or are simply moving away to find more varied prey. Munir had earlier informed me that during his study at Lake Naivasha, he frequently observed fish eagles scavenging on ungulate carcasses during a similar drought period.
A big positive in the last couple of weeks was that I’ve been very kindly allowed to wander on Crescent Island for a day every week. This part of the lake is inaccessible by boat and is privately owned. The situation on Crescent Island is entirely different. With a coastline of only about seven to eight kilometers, there are twelve pairs of eagles tightly packed in, and half are breeding! A great result! The area of water that Crescent Island envelops is the deepest part of the lake and has the steepest shores-a drop in lake level doesn’t mean so much here, the perches are still close to shore, and the shelter of the spit means the water is always calm. The fishing is still good. Walking underneath the nests is a great way of seeing what the birds actually eat; I’ve found tons of fish, cormorant, crayfish, and cane rat skeletons, as well as the odd lamb–I’ve been told a few have been killed by the odd eagle here in the past few months. This however needs verification.
One of the more exciting and sometimes quite scary aspects of fieldwork in Africa is dealing with the constant presence of the local wildlife, and Naivasha is no exception. Quite regularly on counts we pass pods of hippos and a shallow lake with a muddy bottom is not the best place to be when a hippo charges, as happened last week and while walking on Crescent Island, you have to take care of buffaloes as well! Thankfully no more run-ins but I’ve taken to carrying a massive stick with me on my travels as a slight deterrent.
Today was my day off and I had a car for a change, so I spent the morning in Hell’s Gate National Park, close to Naivasha. Because of the volcanic geology and subsequent weathering, its now a stunning landscape with pristine cliff faces where the harder rock has been left behind-as great a place as any to watch raptors. Good sightings today were a pair of hunting Lanner Falcons, a pair of Verreaux’s Eagles with chick, the Ruppells Griffon vulture colonies, and numerous Augur Buzzards. It’s definitely a must visit if you’re a birdwatcher in Kenya, and it has a great walking circuit through a scenic/slippery/steep gorge, complete with hot springs, which is well worth any pain you may experience while doing it!
During the coming week, I’ll be doing another count, and more eagle-behaviour-watching. In the meantime, let’s pray for rain!
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