A Kenyan government push to kill up to 6 million red-billed quelea birds that have invaded farms will have unintended consequences for birds of prey and other wildlife, experts have warned.
The continuing drought in the Horn of Africa It has reduced the amount of native grass, the seeds of which are the queleas’ main food source, causing the birds to increasingly invade grain fields, endangering 2,000 acres (800 hectares) of rice. The birds have destroyed about 300 acres of rice fields.
A single quelea can eat up to 10 grams of grain a day, according to the Food and Agriculture Organization (FAO). Farmers in western Kenya stand to lose about 60 tonnes of grain to birds. In 2021, the FAO estimated that crop losses attributable to birds amounted to $50 million (£40 million) a year.
Spraying with fenthion, an organophosphate pesticide, has been the method of choice for combating pests in Africa, but the chemical has been described by researchers as “toxic to humans and other non-target organisms”.
“Thus, fenthion can indiscriminately injure or kill, with consequent adverse effects on non-target organisms,” the researchers concluded.
Paul Gacheru, species and site manager at Nature Kenya, a local affiliate of BirdLife International, said the method used to control quelea needs to be well informed, as “widespread use of avicides for non-target species can lead to environmental contamination and the mass death of others”. birds and animals.
“There is often poor post-spray site management, increasing the risk of poison-related wildlife deaths, especially among scavengers, hence the need for improved control education and awareness. of quelea”, he said.
With an estimated breeding population in Africa of 1.5 billion birds, ornithologists say there are not enough raptors to wipe out vast quelea colonies or effective, environmentally friendly solutions.
Simon Thomsett, director of the Kenya Bird of Prey Trust, said the culture of ensuring human food security above all else would expand “because of what we now perceive as a probability, due to climate change, as open grasslands that were feeding the queleas the land is quickly converted to farmland.”
In Kenya’s wheat-growing areas, Thomsett added, farmers have sprayed any species of bird that is considered a threat to the farms, “however, some of the birds are there to feed on insects that feed on their wheat”.
But it is the effect that the pesticide can have on the few remaining raptors What worries you the most? “Those on the raptor side of the fence are highly alarmed by the spraying. Today, all the birds of prey [in Kenya] They are in danger of extinction. In any case, how effective has fumigation been in the last 60 or 70 years?”
FAO and the United Nations Environment Program jointly administer the Rotterdam convention, whose objectives include reducing the risks of hazardous chemicals in agriculture. They have been considering including fenthion in Annex III of the treaty, a list of pesticides and industrial chemicals that are banned or severely restricted for environmental or health reasons.
A report prepared by Robert A Cheke of the University of Greenwich and used as a working paper at a 2017 FAO workshop in Sudan recommended alternatives to the use of the chemical, including a forecast and control planning method.
“If the efficiency of control operations could be improved, the amounts of fenthion used could be reduced. One way to improve the efficiency of control strategies is to detect the presence of suitable quelea breeding areas using satellite imagery…or forecast where the birds are likely to breed,” said the report saying.
He added: “Since bird migrations and breeding opportunities are determined by rainfall patterns, it is possible to update forecast systems to predict where birds are likely to breed and therefore focus activities on looking for colonies in areas where the birds are likely to be.”
The Quelea invasion occurs frequently in many African countries. Six months ago, FAO awarded $500,000 to the Tanzanian government to support pesticide spraying, surveillance and capacity building after 21 million queleas invaded fields of rice, sorghum, millet and wheat.