World Migratory Bird Day: Global insect decline threatens birds' survival

Saturday marks World Migratory Bird Day, an annual event to raise awareness and call for global actions to protect billions of birds that are migrating on the planet.

For the first time this year, the theme "Protect Insects, Protect Birds" draws attention to the critical role of insects in the lifecycle of migratory birds and also to the alarming decline of global insect populations.

A report released by the Convention on the Conservation of Migratory Species (CMS), an environmental treaty of the United Nations, shows that one in five migratory species listed by the CMS is at risk of extinction and almost half (44 percent) are decreasing in numbers.

Global insect decline

To understand how important insects are to birds, you need to look no further than bird names, including bee eaters, flycatchers and gnatcatchers. 

Insects are essential sources of energy for many migratory bird species, not only during the breeding seasons but also during their migratory journeys and greatly impact the timing, duration and overall success of their migration.

For example, the timing of bird migration often coincides with peak insect abundance at stopover locations, supplying nourishment for birds before they continue their journeys.

The loss of insects threatens birds' survival and well-being. A scarcity of insects can lead to weakened immune systems, reduced reproductive success and increased mortality rates for both adult birds and their offspring. 

In 2019, the Biological Conservation journal reported that 40 percent of all insect species are declining globally and that a third of them are endangered.

An article on The Guardian reported in 2019 that the total mass of insects is falling by a precipitous 2.5 percent a year, according to the data available at the time, suggesting they could vanish within a century. The rate of extinction is eight times faster than that of mammals, birds and reptiles, according to the article.

A study published on the Biological Letters journal last year concluded the primary drivers of the worldwide insect loss were land-use intensification in the form of greater utilization for agriculture and building development, as well as climate change and the spread of invasive animal species as a result of human trade.

In addition, bugs are not only essential for birds and other animals but also for human beings, as they pollinate plants humans eat, break down waste in forest soil and form the base of a food chain.

Actions to reverse the trend include eradicating pesticide use, prioritizing nature-based farming methods and reducing water, light and noise pollution.

(Cover: Blue-throated bee-eater. /CFP)