Lutembe – Numbering millions, they fly at once in patterns, blocking light from the sky. In a mind-boggling display, they land. In less than a minute, it is quiet again.
A mixed flock of gulls make for interesting watching at the site.
It is baffling how they do not knock each other while in flight or why they can never be hit if one lobbed a stone in their midst.
Experts say they have a complicated navigation system that enables some of them to fly from as far away as Siberia non-stop to Lutembe Bay on the shores of Lake Victoria in Uganda. And these are not stealth bombers. They are terns — migratory birds.
For centuries, Lutembe Bay has been hosting both native and millions of Palearctic migrant birds. They come mainly from the arctic region that includes mainland Europe, Scandinavian countries and as far away as Russia.
They live nine months of the year here and only go back to Europe to breed. Some fly non-stop to and from the Caspian Sea. However, this allure at Lutembe Bay, one of the biggest breeding sanctuaries for migratory birds, is now threatened by human activity if nothing is urgently done.
Achilles Byaruhanga, the executive director of Nature Uganda, says toxic agrochemicals suspected to have leached from the nearby flower farms have been detected in the waters around this Ramsar Site – wetland of international importance.
Byaruhanga says Lutembe Bay is threatened first, by water abstraction – a process where large quantities of water is drawn to water the flower farms.
“Because of this draining, the marshy water at the bay will become muddy, leading to other vegetation to colonize the area, thus reducing not only the habitat and the feeding area for the birds, but also their roosting space,” Byaruhanga says.
Secondly, he says following a 16-year study, agro-chemicals have now been detected in the waters at the bay. This when not controlled, he says, will pollute the waters and not only threaten the fish stocks, but human beings as well.
Lutembe Bay hosts over 70% of the global population of white-winged black terns (Chlidonias leucopterus), large numbers of the grey-headed gulls (Larus cirrocepharus), black-headed gulls (Larus ridibundus) and gull-billed terns (Sterna nilotica).
In 2000, Lutembe hosted almost the entire population of the white-winged black terns — over 3.5 million birds. The birds start coming from September to October every year and go back between February and March.
In Europe, they are again seen between May and June. Every year, the birds come with their young, hatched the previous season.
The hatchlings are left behind to practice breeding. At this stage, their all–white colour changes to black. Others only have their heads change to black. This change of colour is called breeding plumage.
When it is time to go back and breed, the young ones fly as black birds, breed and come back to Lutembe when they are white. The cycle has been going on for centuries.
“If Lutembe is affected, tourism would suffer not only in Uganda, but also in Europe as the breeding pattern of the birds would be destroyed. If they do not get places like Lutembe, they will not breed. These birds must be given an opportunity to practice breeding,’’ Byaruhanga argues.
He says Uganda receives the biggest share of all Palearctic birds in Africa due to the country’s big and fresh water masses.
Other areas in the country that attract migratory birds include the Kazinga Channel and Musambwa Island. The birds feed on insects and small fish.
Records from Nature Uganda show that Uganda earns over $6m (sh15.3b) from birding tourism, doubling earnings from gorilla tracking. Birding is a high-end tourism product, where birders stay long, leaving more money in the country.
The tourism sector is the second largest foreign exchange earner and generated $805m (about sh2.1 trillion) in foreign exchange earnings in the fiscal year 2011/2012. In particular, the sector’s total contribution to GDP is estimated at $1.4b (about sh3.5 trillion), representing 7.6% of GDP; in the year 2011, trailing only remittances from abroad.
Uganda was recently declared a preferred bird watching destination 2013/2014, a development expected to uphold the country as a birder’s paradise.
About half of all bird species in Africa can be found in Uganda. The country supports more than 1,000 bird species, representing about 50% of the bird species in Africa and 11% of the birds’ global population.
Lutembe is home to 280 species of both water and non-water birds. Apart from Palearctic migrant birds, Lutembe is also home to seven globally threatened species like papyrus yellow warbler, papyrus gonolek, shoebill, African skimmer great snipe and Madagascar Squacco, among others.
A team from Nature Uganda spotted a new migrant species, the great knot, in 2010. The site also hosts hundreds of Palearctic ducks like the garganey (Anas querquedula).
At an altitude of 1,130 metres, covering an area of about 800 hectares, Lutembe Bay is shallow, papyrus-fringed, and almost completely cut off from the main body of Lake Victoria by two papyrus islands.
The biggest congregations of the European birds at Lutembe are gulls and terns, which roost on islets when the water level is low, between September and March.
En-route to Uganda, the terns have stop-over in Sudan and Egypt along the River Nile while the gulls can fly from the Caspian Sea to Lutembe non-stop.