Monday, June 21, 2010

First catch your flamingo!

Dr Graham McCulloch has been monitoring the globally threatened Lesser Flamingo in the Makgadikgadi Pans for over a decade and, as is always the case with research, the more you find out about your subject, the more interesting it becomes and the more you realize how little you know!

One fact that is apparent from the monitoring data is that Lesser Flamingo numbers have been steadily increasing. A count of 77,491 Lesser Flamingos at Sua in 2009 exceeded the total estimate for Southern Africa (~65,000). This raises the interesting question: Has the Southern African flamingo population increased by improved breeding success due to better conditions, or has the local population been augmented by an influx of birds from further afield? Because flamingos are highly nomadic, and can travel vast distances, it has long been speculated that birds from East Africa sometimes visit Southern Africa, and vice versa. This could mean that there is one large population with birds moving to and from the best feeding and breeding conditions on the continent; if this were the case, it would have important implications for the conservation of the species.

To find out whether there is any connection between the Southern African and East African flamingo populations, two different but equally innovative approaches could be adopted. Firstly, now that DNA analysis is possible and commonplace, an investigation into the genetics of birds from both areas could tell if there is one large, intermixed population, or two distinctly separate groups. Recent studies comparing the DNA of populations from both regions, using blood samples from the Makgadikgadi, collected by Graham during some ringing excercises some years ago, and samples taken from the soda lakes in East Africa suggest similar DNA and favour a connection between the two populations, or the existence of one interconnected population. Secondly, and also resulting from technological advances, it could be possible to fit individual flamingos with tiny transmitters that send a signal to orbiting satellites which pinpoint their position and relay the information back to Earth! Incredible though this may seem, small transmitters weighing a mere 35 grams are now available with minute but efficient solar panels, that can be fitted to relatively small birds such as the Lesser Flamingo, and this is the approach adopted by Graham in his research.

During 2001, satellite transmitters were deployed on eight Lesser Flamingos from Sua Pan; these were battery-powered (without solar panels) and during the two years that they continued to function, Graham was able to determine that birds from Sua move all over Southern Africa, to the west coast of Namibia, Kamfers Dam in South Africa and even into southern Mocambique. Frustratingly however, none of these birds moved to East Africa! This does not mean that the Lesser Flamingos from Sua Pan don’t go to East Africa – only that these few individuals did not go there during the period of the study!

Base camp for flamingo capture (Photo: P Hancock)

Recently, Graham has been collaborating with the Max Planck Institute in Germany, and they have provided six of the latest solar-charged transmitters for fitting on Lesser Flamingos. This is easier said than done – just how does one catch a free-flying flamingo in the vastness of the Makgadikgadi Pans? In 2001, Graham caught the birds by setting hundreds of small noose-traps in the flamingos favoured feeding areas in the shallows of Sua Pan – once a bird’s foot becomes entangled in the noose, it can be captured without injury or undue stress. But there is more to this technique than betrayed by a simple sentence, as can be imagined! Firstly, it is important to identify the preferred feeding areas on a daily basis, and then set the snares at first light – thereafter, it is a question of waiting patiently at a distance until the birds eventually return and one gets caught!

The first flamingo capture exercise this year took place during early May, just as a practice run, since it was apparent that suitable conditions for initiating this part of the project were returning. It is important to fit the transmitters just before Sua Pan dries up, so that the birds can be relatively easily caught, and will soon start moving away from the Pan – it is pointless paying for the expensive downloads of data from the satellite if the birds are not travelling more than a few hundred metres from one feeding area to another! Two adults were caught in the same number of days – and then late rains put paid to any further capture attempts as Sua Pan filled with water!

A flamingo in the hand is worth measuring in as many ways as possible (Photo: P Hancock)

By mid-June, the shallow, saline waters of Sua had evaporated sufficiently to permit a second capture attempt to be made. Alas, after a few days of setting the trap-lines early in the morning and retrieving them in the evening, no flamingos had been caught - round 1 to the researchers, round 2 to the flamingos!

This is where the project stands at present – we are all looking forward to round 3 so that the real work can begin – that of unraveling the movements of these flambouyantly successful nomads. This blog will provide regular updates, particularly once data become available showing where the birds are, so that the information on their movements can be used to better conserve the species.

Weary team members return at sunset - empty-handed (Photo: P Hancock)

Friday, June 11, 2010

Birds of Lake Xau - 1964

Reading Smithers (1964) Checklist of birds of the Bechuanaland Protectorate and Caprivi Strip gives one an insight into conditions in the country during the middle of the last century. Particularly fascinating is his account of birds at Lake Dow (Xau) – the frontispiece of the book depicts a Gull-billed Tern foraging over Lake Xau, a Category A rarity (seen less than 10 times in recent years). Here are some of the waterbirds seen at the lake during the late fifties and early sixties, and which may be seen there again when the lake floods in future:

Pink-backed Pelican – January 1959 many were seen in immature plumage
African Darter
Black-crowned Night-Heron
Squacco Heron
Black Heron
Great Egret
Yellow-billed Egret
Little Egret
Grey Heron
Goliath Heron – individuals in immature plumage seen in January
Saddle-billed Stork
Marabou Stork – seen in flocks of 50 at a time
African Sacred Ibis
Glossy Ibis
African Spoonbill
Lesser Flamingo – no nests of this species found at the Lake
Fulvous Duck – occurs in large numbers, January 1959, flocks of 200 at a time
Egyptian Goose
Spur-winged Goose
Comb Duck
Cape Teal – a few seen on Inkokwane Pan near Lake Dow
Red-billed Teal – in huge flocks
Hottentot Teal – common, occurring in flocks of upwards of 50
Southern Pochard
African Fish-Eagle
Purple Swamphen
Red-knobbed Coot
Wattled Crane
Grey Crowned Crane
African Jacana
Water Thick-knee
Kittlitz’s Plover
White-fronted Plover
Chestnut-banded Plover – an immature, hardly able to fly, taken on 18 January
Caspian Plover
Greater Painted-snipe
Black-winged Pratincole
Grey-headed Gull
African Skimmer
Gull-billed Tern – recorded in January 1959
Whiskered Tern – in breeding plumage December 1962 and January 1963
Kurrichane Buttonquail – breeding 15 January 1959, c/4 fresh
Yellow Wagtail – particularly common at cattle kraals
Sedge Warbler
Lesser Swamp-Warbler
Southern Red Bishop – in breeding plumage
Yellow-crowned Bishop – in full breeding plumage in January
African Quailfinch

This variety of birds needs a diversity of habitats, including open water, reeds and sedges, aquatic waterweeds, and short grasslands near water, all of which would have been found around the lake fifty years ago. Difficult to imagine, isn’t it?