A combination of grassland habitat loss through land use alteration and agri-chemical poisoning are the primary causes of the decline in Blue Crane populations. The alteration of large tracts of grasslands to mono-cultures of maize crops and commercial afforestation has limited the suitable open grassland habitats required for successful breeding and foraging. Over 1,3 million hectares have been converted to forestation in South Africa, mainly in the wetter eastern parts, there is a high likelihood that this land use conversion will increase in the future, particularly in KwaZulu-Natal and the Eastern Cape Provinces, as the department of Forestry aims to add 10 000 ha of net new afforestation a year.
The documented decline of Blue Cranes has coincided with many reported cases of poisonings from all parts of the country, although proportionally more have been reported in the Western and Eastern Cape Provinces (where large populations of Blue Cranes are found and can be expected to occur in crop fields). Poisoning in the past has been through intentional and deliberate poisoning of cranes causing crop damage, the inadvertent poisoning aimed at killing other species causing crop damage, or accidentally through the normal application of agri-chemicals to croplands. Currently, poisoning cases are as a result of farm workers either directly poisoning cranes, or inadvertently poisoning them when baiting grain for gamebirds, for extra food protein. Another significant threat is the removal of young Blue Crane chicks, prior to fledging, from the wild to be kept as pets, for food, or to sell to bird breeders.
A further significant threat results from collisions with power-lines, and more recently with wind-turbines on wind farms. These hazards pose a constant threat to flying cranes, particularly young birds, as they tend not to scan the the area ahead of themselves when flying. Eskom has recognised the hazard that power-lines pose to all large birds and have worked with conservation bodies in hanging markers on power-lines in known bird corridors, nevertheless it is believed that most bird mortalities caused by power-line collisions go unreported