Park Island: Horny Honkers
The cache, a camo-taped tablet pot, is hidden on the east side of the island just off the trail leading around the southern tip of the island. As the cache was being placed the distinct honking calls of the male geese could be heard from where a gaggle of Egyptian geese was gathered on and around the edge of the small mainland peninsula to the south adjacent to the island.
To reach the cache location: park at the end of Park Island Way @ S 34 05.332 E 18 28.455 and, after securing your vehicle (no valuables visible), enter through the pedestrian gate (open daily from 06h00-20h00). After crossing the bridge, take the first track to the left (south) and follow this to the cache location.
The Egyptian goose (Alopochen aegyptiaca) is a member of the duck, goose, and swan family Anatidae. It is native to Africa south of the Sahara and the Nile Valley and is the most widely spread of all African waterfowl. The generic name is based on Greek words for ‘fox’ and ‘goose’ referring to the ruddy colour of its back.
It is not actually a goose, but a shelduck - a cross between a duck and a goose. It has many characteristics of a duck, but also some external traits of a goose
It was considered sacred by the Ancient Egyptians who domesticated them, and it often appeared in their artwork. The Greeks and Romans also had them in their domestic flocks.
Because of their popularity as an ornamental bird, escapees are common and feral populations have become established in several parts of the world including Western Europe and North America. A Specieswatch article in the Guardian of 25 May 2014 reported that ‘after struggling to survive Britain's cold winters for more than 300 years the Egyptian goose is undergoing a population explosion’ . . . it was ‘brought to Britain in the late 17th century as an ornamental bird for the lakes of country gentlemen’.
It swims well, and in flight looks heavy with slow wing-beats - more like a goose than a duck, hence the 
English name. It is 63–73cm long with a wingspan of 134-154cm, weighs ~1.4kg and lives up to 25 years. When flying it looks goose-like and heavy, They may fly together in an irregular V-shape or a long line.
Both sexes have identical plumage but males average slightly larger. Plumage can vary with some birds greyer and others browner, but this is not sex- or age-related. Much of the wings of mature birds is white, but at rest the white is hidden by the wing coverts. When it is aroused, either in alarm or aggression, the white begins to show. In flight or when the wings are fully spread in aggression, the white is conspicuous.
They remain together in small flocks during the year, primarily for protection. During the breeding season they pair up, but otherwise stay with their flocks. They are mostly non-migratory and will generally move about only if water in their area is in short supply. They are good swimmers but most of their time is spent on land. During the day they may wander away from the water in search of food in grasslands or agricultural fields but at night always return to the water.
The voices and vocalisations of the sexes differ, the male having a hoarse, subdued duck-like quack which seldom sounds unless it is aroused. The male attracts its mate with an elaborate, noisy courtship display that includes honking, neck stretching and feather displays. The female has a far noisier raucous quack that frequently sounds in aggression and almost incessantly at the slightest disturbance when tending her young.
II breeds widely in Africa except in deserts and dense forests, and is locally abundant. It is mainly terrestrial and will also perch readily on trees and buildings.
It is primarily herbivourous, typically eating seeds, leaves, grasses, and plant stems as well as grains, 
potatoes and other vegetables. Occasionally, it will eat locusts, worms, or other small animals. Since it tends to eat mostly on the ground, it helps disperse food seeds to other areas through their droppings, break up the soil and speed up the decomposition of dead plants.
Both sexes are aggressively territorial towards their own species when breeding and frequently pursue intruders into the air, attacking them in aerial ‘dogfights’.
Egyptian geese have been seen attacking aerial objects such as drones that enter their habitat as well. Neighbouring pairs may even kill another's offspring for their own’s survival as well as to access more resources. They usually get away from danger by walking, seldom flying, except when surprised.
They are monogamous and a pair stays together for life. Males are aggressive during mating. Each an elaborate and noisy courtship display, producing unusually loud honking noises for the purpose of attracting a female. They breed in spring or when the dry season ends.
A pair nests on its own on the ground, sheltered by vegetation, sometimes higher on a ledge or in a tree, or in an abandoned nest of another species up in a tree, or inside a hole - especially in mature trees in parkland. The female builds the nest from reeds, leaves and grass.
The female lays 5-11 creamy white eggs which she incubates for ~28-30 days. Both the male and the female then feed and care for the chicks. The young fledge at about 60-75 days, remaining under the care of their parents for almost 4 months. Chicks, when born up in high nests, have to be very courageous to jump out into the void when leaving the nest. Their parents do not help, but call from the ground with encouragement to make this sometimes vertiginous fall. The chicks reach maturity when they are 2 years old.
For more information on the bird, see here. See Urban Critters for an entertaining short video on how the geese have adapted to the urban environment, here and here for videos of the geese fighting.
For a full list of the fauna recorded in the Reserve, including some 166 bird species, see here.