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The Grey-Crowned Crane - Balearica regulorum by
Janis O’Grady The claim to fame of the Grey-Crowned Crane is that it is one of the only cranes to roost in trees and the most primitive crane – it is thought to resemble the many pre-Pliocene fossils from North America and central Asia. "The first crane-like birds, which appeared in the age of dinosaurs, were somewhat similar in body dimensions to a modern crowned crane or its smaller and more aquatic relative, the limpkin" (Matthiessen 2003).
The Grey-Crowned Crane is globally restricted to Africa where the South African population, and the populations of Zimbabwe, Botswana and Namibia, make up the smaller population of the two subspecies. Within South Africa, this ancient crane has been sighted in the moist, higher rainfall regions of the Eastern Cape, KwaZulu-Natal and the North-eastern Free State, as well as the Eastern regions of Mpumalanga. They require a mixture of wetlands and grasslands for summer breeding and foraging although they are increasingly found in man-modified habitats (agricultural lands). The overriding conservation challenge is therefore to develop sustainable management alternatives for their co-existence with agriculture on privately-owned land. This species faces widespread degradation of its breeding and feeding habitats and is still persecuted by landowners in some areas – who think that the bird is eating crops whereas they are more likely to be eating insects on those crops (McCann 2002). Over the past two decades, Grey-Crowned Crane numbers have declined by about 15% due to increased human-induced impacts. 4.1. Biological needs Grey-Crowned Cranes nest within or on the edges of wetlands where they build a strong nest from the tall wetland plants, cleverly concealed from predators and the prying eyes of people. They like to forage in open grasslands adjacent to wetlands where they eat grass seeds, insects and other invertebrates – they have also taken to agricultural lands including pastures, fallow fields, maize crops, cabbages and harvested croplands. This generalist feeding strategy has allowed this species to adapt to human settlement better than the Wattled or Blue Cranes and it is regularly now found in this transformed habitat. Unlike other crane species, this crane roosts in trees – its voice has considerable harmonic development and can be heard for miles – cranes use many different calls to communicate and can be very boisterous upon returning to the roost (Cooley 1993). Non-migratory, they do move around locally and in the winter months, large flocks of non-breeding Grey-Crowned Cranes can be found dancing and calling before the onset of the summer breeding period. Intensification of agriculture, tourism development and industrialisation are threatening grasslands at a terrifying rate and indigenous species like cranes are being forced into smaller territories. Wetlands also are alarmingly threatened by human impacts and forcing the Grey-Crowned Crane into populated areas where danger lurks. 4.2. Breeding Grey-Crowned Cranes also reach maturity at the age of three to four years and once they have found a mate, they usually lay 2 – 3 large smooth eggs in a wetland nest surrounded by tall reeds, secluded from predators. These spring and summer breeders incubate their eggs for about 30 days and take their chicks out onto a nursery area of flattened reeds before they venture into the real world to forage. Chicks fledge at 3 – 4 months and leave their parents when almost a year old to join one of the non-breeding flocks where they look for a mate. 4.3. Threats As already mentioned, the Grey-Crowned Crane is threatened with habitat loss (wetlands and grasslands) as well as management of these ecosystems: burning of firebreaks and grazing methods have to be properly controlled by the farmer if Grey-Crowned Cranes are resident on his land. However, these species are better adapted to land-use change than its Wattled and Blue Crane cousins. Powerline collisions are another prevalent threat to this primitive bird especially when it is flying in flocks in misty or rainy conditions, to and from tree roosts. The Grey-Crowned Crane now has a price on its head South and Southern Africa due to its extreme beauty and sacred status in the Eastern Cape of South Africa and Uganda in Southern Africa (where it is the national bird). Recently the human threat has intensified and many Grey-Crowned Crane chicks and eggs are being taken out of the wild for the international bird trade, or to keep as status symbol pets. Poisoning is another problem faced by this crane and whether deliberate for food or unintentional when secondary, this threat requires strict management of the use of agrochemicals. In the past, farmers killed cranes deliberately if they were perceived to be causing crop damage; today, farm workers often put down poisons to catch cranes or other species for extra food protein, ignorant that they are putting themselves in danger. Other threats include domestic dog predation, fences, and "accidental" shootings (McCann 2002). 4.4. Responses to threats With only some 4 000 Grey-Crowned Cranes left in South Africa today, conservationists are increasing their efforts to understand the bird better, both biologically and geographically. SACWG fieldworkers are participating in a national education and awareness programme aimed at farm workers (the eyes and ears of the land), school pupils and teachers, other groups and networks and the general public. Regular media articles and marketing drives assist with funding measures and fieldwork includes monitoring, population management, threat reduction and more. Farmers are one of the main "target groups" as very few cranes breed in reserves – most are found on private land and it is up to the landowners (our 'crane custodians') now to decide whether these birds have a future or not. Solutions need to be provided to landowners experiencing crop damage by cranes through methods of preventing cranes eating the crops or establishing crane feeding restaurants during periods of crop sensitivity – one SACWG fieldworker is carrying out research into this issue, including research into the breeding success of the bird in the Eastern Cape where impacts from the illegal trade are highest. A Population and Habitat Viability Assessment (PHVA) has not yet been planned for the Grey-Crowned Crane but it will have to be considered with the intensification of threats to the species and the shrinking of its natural range. In the words of Aldo Leopold (1949): "Some day, perhaps in the very process of our benefactions, perhaps in the fullness of geologic time, the last crane will trumpet his farewell and spiral skyward from the great marsh…"
The three crane species of South and Southern Africa |
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