Delta Park in Victory Park attracts some unusual birds, with at least 40 species making it their home.
The orange-breasted bush shrike, the arrow-marked babbler, and the white-crested helmet shrike have all visited the park in recent times, usually driven by drought in their normal bushveld habitat, says ornithologist Geoff Lockwood, the resident manager and education officer at the Delta Environmental Centre.
He says that the sooty falcon, normally a resident of the east coast, has been sighted at Delta. “Note that with long-distance migrants, there is a greater chance of birds becoming ‘lost’ and turning up in strange locations.” The sooty falcon breeds in north Africa and the Middle East.
Over 900 different species of birds have been recorded in South Africa – almost 10 percent of all the bird species in the world. And almost 200 have been sighted in the park. Several small mammals have found a home there too – genets, shrews, hedgehogs, mole rats and mongooses.
But the biggest bird success story at the park is the nesting spotted eagle owls over the past 29 years. Over that time, there have been three new females and five males, producing dozens of owlets in the specially constructed owl nesting box on the roof of the centre. Significantly, the parents don’t leave the park to find food for themselves and their young – there is plenty to hunt there.
The park consists of 104ha of parkland, containing three dams, and two fenced bird sanctuaries of 10ha, each with a dam. The centre in the middle of the park is run as a non-profit organisation, leased from the City’s property company.
It was established in the 1930s as a sewage treatment plant, at the time one of the most advanced treatment plants in the world. But as Johannesburg grew its capacity became too small, and in 1963 the plant was moved to Diepsloot. In 1975, a section 21 company was registered and the SA Nature Conservation Centre came into being. In 1992, it changed its name to the Delta Environmental Centre.
Joburg City Parks, the custodian of 2 343 parks in the city, takes care of Delta Park. It cuts the grass, plants trees, removes refuse, and hires out the park. The centre runs educational programmes – from pre-school to a registered diploma course in environmental education.
It has established a sensory trail and water wise garden in the park.
Delta is planted mostly with exotic trees, but birds are not fussy – if the trees offer good roosting and nesting opportunities, plus food in the form of seeds or berries, they’ll take up residence. For instance, the Chinese elms provide seeds for doves, and the eucalyptus trees attract bees, which attract the bee-eating birds. Chinese privet bushes produce purple berries which the rameron pigeons eat.
Lockwood says that the exotics are being actively removed, especially in the two bird sanctuaries, and are being replaced by indigenous trees. Already, 40 have been planted in the past year or two. There are 100 indigenous trees in the park now.
“We have to replace them slowly – radical changes mean we could lose bird species,” he explains.
Visitor numbers at Delta have trebled since the installation of a playground area three years ago – with dog-walkers, mountain-bikers and families enjoying this great outdoor space.
Exhibits and displays
The centre has environmental and educational exhibits and displays, including an informative display on the Lesotho Highlands Water project, the geology of the Witwatersrand and a fig tree exhibit with its root structure visible, positioned inside an old tank.
A natural history museum houses displays depicting a variety of biomes, including wetlands, mangrove swamps, desert and grassland ecosystems. The Day in the Veld simulates a day, from dawn to dusk, in the bushveld, with its various sounds and sights.
The Gold Fields Discovery Centre allows groups to participate in experiments and activities on soil, energy, air and water. In addition, there are discovery rooms: the Room of Life; the Energy Room; the Water Adventure Room; and the Earth Science Room.
An exciting project that involves observing the birds at Delta Park is the South Africa Bird Atlas Project 2 (SABAP2). It is a joint project of the animal demography unit in the department of zoology at the University of Cape Town, BirdLife South Africa, and the South African National Biodiversity Institute.
According to the website, SABAP2 is an “update and refinement of the first Southern African Bird Atlas Project which ran from 1987-1991 and culminated in the publication in 1997 of two volumes on the distribution and relative abundance of southern African birds”.
Participants usually spend two hours charting bird sightings, and entering their data in a 17 000-grid cell programme, of which 54 percent has already been covered.
The aims of the project are to establish a rigorous scientific platform for tracking the impact of environmental change on birds in the region by means of standardised data collection on bird distribution; and to increase public participation in biodiversity data collection, and public awareness of birds, through large-scale mobilisation of citizen scientists.
“During the past 15 years bird distributions in southern Africa have continued to change, possibly more rapidly than during the previous 30 to 40 years,” indicates the website. These changes are due to “large-scale landscape changes, resulting in widespread habitat loss, transformation and fragmentation, and in some cases habitat creation, coupled with climate change and invasion, have contributed to changing bird distributions”.
Monitoring these changes is vital if proper and effective management plans to conserve bird populations and diversity in southern Africa are to be implemented. “Borne out of recommendations from SABAP1 and from recent calls from both the scientific and birding community, SABAP2 was identified as the project to lead the way in monitoring these ecological changes.”
The success of SABAP1 can be seen in the adoption of its methods by other projects: the Southern African Frog Atlas Project piggy-backed and modified the technology to produce the first comprehensive account of the distribution and status of all 115 known frog species in South Africa, Lesotho and Swaziland.
The concept was then transferred to reptiles and currently the Southern African Reptile Conservation Assessment is collecting information on the distribution and diversity of reptiles in the three countries. The methodology has also been applied to the Southern African Butterfly Conservation Assessment.
Its mapping and grid system has also been adopted internationally.
So, what does SABAP2 mean for Delta Park? “Probably better phrased the other way – the level of coverage that we have achieved for the Delta pentad will allow the ADU [animal demography unit] at UCT to statistically track trends in the relative abundance of birds in the Johannesburg area,” explains Lockwood.
It has also had an effect on tourism, encouraging foreign visitors to visit parks in Joburg, particularly the Cumberland Bird Sanctuary in Sandton, and the President Ridge Bird Sanctuary in Randburg.