Zeekoevlei #3: Cool Bird!
The cache, a small, screw-capped camo-taped plastic tube, is hidden on the eastern side of this large lake which forms a major part of the False Bay Nature Reserve (FBNR) - a unique area of incredible biodiversity. On World Wetlands Day 2 February 2015 FBNR was designated as a Ramsar site: a wetland of international importance, the only one in Cape Town and one of 22 in South Africa.
Whilst searching for a suitable hide location, a small 'squadron' of these unmistakeable huge birds flew low across the vlei before landing and settling near a reed bed on other side.
To reach the cache location: take the M17 Strandfontein Road to the junction with Dollarbird Road @ S 34 03.198 E 18 31.771. Turn west here and follow the road around the traffic circle and on to the FBNR (Zeekovlei section) entry gate @ S 34 03.290 E 18 31.227. This is open 07:30-19:30 in summer and 07:30-18:00 in winter - entry is free.
After completing brief formalities follow the road around the long left hand bend to the junction at S 34 03.628 E 18 31.248 and turn right (west) to access the lakeside road and picnic areas. Turn left at the T-junction and park anywhere close to the cache location.
The great (or eastern) white (or rosy) pelican (Pelecanus onocrotalus) breeds from southeastern Europe through Asia and Africa, in swamps and shallow lakes. It is a huge bird 140-180 cm long with an enormous 29-47 cm pink and yellow bill and dull pale-yellow gular pouch. The wingspan of 226-360 cm is the largest for any flying animal except the great albatross. The adult maleweighs 9-15 kg. Life expectancy is up to 30 years in the wild and up to 50 or more in captivity.
The male has a downward bend in the neck and the female has a shorter, straighter beak. Both male and female are similar, but the female is smaller and has brighter orange facial skin in the breeding season. It is mostly silent but has a variety of low-pitched lowing, grunting, and growling calls. The flight call is a deep, quiet croak while at breeding colonies, it gives deep moooo calls. Listen here and here.
The African population of about 75,000 pairs of the great white pelican is resident. Overall, it is one of the most widely distributed pelican species. It usually prefers shallow, (seasonally or tropical) warm fresh water. In Africa, it occurs mainly around freshwater and alkaline lakes and may also be found in coastal, estuarine areas.
It is highly sociable and often forms large flocks (see here). A group of pelicans is called a brief, pod, pouch, scoop, colony or squadron!
GWPs live, breed, migrate, feed, and fly in formation in large colonies. Fishing is usually over by 8-9 am and they spend the remainder of the day on small islands or sandbars resting, preening, and bathing. They bathe by ducking their head and body into the water while flapping their wings. When hot, they will spread their wings or gape to cool down. Large flocks may congregate at traditional roosts, these places also being used after fishing tips as daytime resting sites. They sometimes perch in trees, but usually roost on the ground. To defend his territory, a male threatens intruders by gaping, clapping his bill, and bowing, attacking with his bill if necessary.
It is well adapted for aquatic life. The short strong legs and webbed feet propel it in water and aid a rather awkward takeoff from the water surface. Although cumbersome on land, in flight it is an elegant soaring bird, with the head held close to and aligned with the body (see here for a pod taking off). Its flight consists of a few slow wingbeats followed by a glide. Once aloft, the long-winged pelicans are powerful fliers, however, and often travel in spectacular linear, circular, or V-formation groups (see here). They can fly >500km without stopping and with a top speed of 65 kph.
It is a piscivore (eats mainly fish) leaving its roost to feed early in the morning and may fly over 100 km in search of food, requiring some 0.9-1.4 kg of fish every day - often the commonest cichlids, including many species in the Haplochromis and Tilapia genera. The largest colony - >80,000 birds on Lake Rukwa, Tanzania - eats 35 million kg fish per year!
Its pouch is simply as a scoop. As the pelican pushes its bill underwater, the lower bill bows out, creating a large pouch which fills with water and fish. As it lifts its head, the pouch contracts, forcing out the water but retaining the fish. A group of 6-8 will gather in a horseshoe formation in water to feed together. They dip their bills in unison, creating a circle of open pouches, ready to trap every fish in the area. Most feeding is cooperative and done in groups, especially in shallow waters where fish schools can be corralled easily, though they may also forage alone as well.
As an opportunistic forager, it is however not restricted to fish and will sometimes eat chicks of other birds (see video here) such as the well documented case off the southwest coast of South Africa.[21] Here, breeding pelicans from the Dassen Island prey on chicks weighing up to 2 kg from the Cape gannet colony on Malgas Island - as happens in Walvis Bay where eggs and chicks of Cape cormorants are fed regularly to young pelicans.
They also rob other birds of their prey. During periods of starvation, they also eat seagulls and ducklings. Thegulls are held under water and drowned before being eaten headfirst. A flock of captive great white pelicans in St James's Park, London is well known for occasionally eating local pigeons, despite being well-fed (see here).
Breeding is all year around in Africa with large numbers breeding together in colonies. Most nest in scrapes on the ground lined with grass, sticks, feathers and other material.
1-4 chalky white eggs are laid and incubation takes 29-36 days. Chicks are naked when they hatch but quickly sprout blackish-brown down. The young are cared for by both parents. The colony gathers in 'pods' around 20-25 days after the eggs hatch. The young fledge at 65-75 days of age. Around 64% of young reach adulthood attaining sexual maturity at 3-4 years old.
They are often protected from bird-eating raptors byvirtue of their own great size, but eagles may prey on their eggs, nestlings, and fledglings. Occasionally they are attacked at their colonies by mammalian carnivores, such as jackals and lions. As is common in pelicans, the close approach of a large predaceous or unknown mammal, including a human, at a colony will lead the pelican to abandon its nest in self-preservation. Additionally, crocodiles, especially Nile crocodiles in Africa, readily kill and eat swimming pelicans.
It is often kept in captivity in zoos or in semi-wild colonies such as that in St. James's Park, London. The ancestors of this colony were originally given to Charles II by the Russian ambassador in 1664 which initiated the tradition of ambassadors donating the birds.
Today, because of overfishing in certain areas, white pelicans are forced to fly long distances to find food. They are exploited for many reasons - the pouch is used to make tobacco bags, their skin is turned into leather, the guano is used as fertiliser, and the fat of its young is converted into oils for traditional medicine in China and India. In Ethiopia, they are shot for their meat.
See here for an extraordinary short video of teaching a tame GWP to fly and fish!