Furadan, a highly toxic insecticide and nematicide, was the object of fierce protests by conservationists in the mid 1990s after it was discovered that rice farmers were poisoning ducks and other waterfowl when they applied the chemical on their rice paddys. The intervention of the conservationists had led to the ban on the use of granular Furadan which was deemed to be attractive to grain-eating birds. The liquid (or flowable) form was not affected by the ban although it is not registered in Kenya.

 Furadan (chemical name: 2,3-Dihydro-2,2-dimethyl-7-benzofuranol methylcarbamate), also known by various trade names including Curater, Bay 70143, Rampart and Furacarb is an insecticide of a class described as carbamate. It works through cholinesterase inhibition.

Cholinesterase is one of many important enzymes needed for the proper functioning of the nervous systems of humans, other vertebrates, and insects. Carbamates like Furadan work against undesirable insects by interfering with, or ‘inhibiting’ cholinesterase and rendering nerve signal communication ineffective. In mammals and birds it causes twitching, trembling, paralyzed breathing, convulsions, and in extreme cases, death. Exposure to the pesticide is by ingestion, inhalation, or contact.

 Because it is a systemic chemical, it is absorbed in the body of target organisms where it builds to fatal levels. At these levels secondary poisoning can result from consumption of the poisoned carcases resulting at times in death.

 Carbofuran is known to be highly toxic to birds. In the US before the granular formulation was banned by the US Environmental Agency (USEPA) in 1991, it was blamed for the death of millions of birds. A single grain is sufficient to kill a bird (a quarter teaspoon – 1ml – is fatal to humans). Birds which consume grasshoppers and other insects that have been exposed to the chemical also end up – more often than not – dead.

 Carbofuran is linked to the death of hundreds of bald eagles and other American birds such as bluebirds, pintails, robins, owls, swallows, grackles, killdeer and kestrels. Single poisoning incidences have resulted in as high as 2,450 individual birds. More than 100 bird species have been documented as having died from carbofuran poisoning in the US. Biologists of the US Fish and Wildlife have stated – rather accurately – that “There are no known circumstances under which carbofuran can be used without killing birds”

 It is clear that similar secondary exposure is responsible for the mass fatalities of our vultures. The most disturbing reality is that pastoralists do not, in most cases, grow commercial crops for which Furadan was developed. This is a case where the pastoralists are purchasing these chemical specifically to eliminate predators with a resultant catastrophic decimation of scavengers.

 While ongoing discussions mention the pastoralists’ need to protect their herds from the increasing attacks on livestock by predators, the knock-on effect on vultures – not to mention the high rate of loss of large predators – is inexcusable. There are of course calls to find alternative ways of deterring livestock predation by wildlife but these may take some time to find. By then, the local vulture – and possibly raptor and predator populations – may have been wiped out.