Migratory bird species hit by food shortage as insects killed

IN MARKING World Migratory Bird Day on Saturday, attention was focused on the importance of insects and their impact on migratory birds.

The theme: “Protect Insects, Protect Birds” highlighted the importance of insects for insectivorous migratory birds which rely on a variety of insects for their energy as they migrate north in winter. A reduction in insect populations threatens the survival of these species, the Endangered Wildlife Trust (EWT) said.

“The decline in insects worldwide is being caused by not only habitat loss, but also the use of pesticides, which have the knock-on effect of increasing bird and other insectivore mortalities.

“Although no official figures have been released yet, early indications are that there have been fewer lesser kestrels and amur falcons visiting South Africa this year,” EWT said.

While insect declines may be a contributing factor, it may also be attributed to the fact that there was exceptional rainfall further north in East Africa, resulting in migratory birds remaining in areas of abundant resources instead of travelling further south for food – to South Africa, for example. That is why there may have been lower numbers of migratory falcons and other species such as white stork in southern Africa this past summer, the EWT said.

Counts conducted by EWT field officers, particularly in the Northern Cape, North West, Mpumalanga and Kwazulu-natal, in January and February, range from thousands of falcons and kestrels in the Hanover area on January 20, 2024 to only a few hundred at a roost in Standerton, Klerksdorp, in Underberg, Victoria West and the Beaufort West Areas.

Between 160 and 180 of the raptors were counted at De Aar in February this year. These figures are still being collated for official publication.

The report on the Status of the World’s Migratory Species and the review of the Mid-term Implementation Action Plan to Conserve African-eurasian Vultures (Vulture MSAP) released at the UN Convention on Migratory Species in March 2024 showed that over the past 30 years, 70 Cms-listed migratory species – including the Egyptian vulture – have become more endangered.

The report highlights habitat loss, degradation and fragmentation, as well as over-exploitation alongside climate change, pollution and invasive species as having profound impacts on migratory species.

It recognises that the widespread use of pesticides in intensive agriculture is a key factor in the reported declines in insect populations. Many of these substances also have a secondary poisoning effect on birds that may feed on insects killed by the pesticides.

“The decline in insect numbers can result in food shortages for a wide range of species, not least the many insectivorous migratory birds heading north to Europe, the Middle East and Asia for the winter,” EWT said.

Besides a shortage of insects, an overpopulation of insects in some areas due to, for example locust plagues, can also affect migratory birds as plant health is compromised and agriculture is harmed. Extensive use of certain pesticides in locust and quelea control in Africa also has a substantial impact on non-target species, including a wide range of migratory raptors that make use of these species as a food source, EWT noted.

“The EWT joins countries and communities around the world to support the need to expand efforts to not only tackle the illegal and unsustainable taking of migratory species, but also to increase efforts to tackle climate change, habitat loss for both migratory birds and insects and to address issues such as noise, chemical and plastic pollution which affects all migratory species.”

Whatsapp your views on this story at 071 485 7995.