Between our paved backyards and potted plants, our drained wetlands and vast areas of monoculture – there is silence. Nearly six decades since Rachel Carson’s book Silent Spring exposed the devastating effects of DDT on humans and wildlife, bird populations around the world are plummeting. Birds of all kinds are vanishing as a result of human impact on the environment:
Half of New Zealand’s indigenous bird species are in serious trouble. Globally, more than 1300 species of birds – one in eight, reports the International Union for Conservation of Nature (IUCN) – are threatened with extinction. The German Green Party warned last year, “The situation of birds is dramatic. A ‘silent spring’ could be on the horizon.”
In France, Benoît Fontaine, conservation biologist at the National Museum of Natural History, describes the situation as “catastrophic”, adding, “Our farmland is turning into a real desert.” In June, 232 scientists across the globe signed a petition calling for a ban on a specific family of insecticides called neonicotinoids, citing their devastating effect on beneficial insects and their contribution to “the massive losses of global biodiversity”. The journal Nature found a correlation between declines in some bird populations and the use of pesticides.
Indeed, the removal of insects from the food chain has seen headlines warning of “ecological Armageddon”. In the UK, where the hedgerows in which birds nest are disappearing, farmland bird numbers have more than halved since 1970. In France, in less than two decades, a third of birds have disappeared from the countryside. Meadow pipit numbers have declined by 68%, skylarks by 50%, grey partridges by 90%. Across Europe, the number of house sparrows, usually quick to adapt to urban environments, has tumbled as a result, it is thought, of air pollution and poor food. In Germany, populations of a third of all bird species declined significantly this century.
The human impact on bird populations is becoming impossible to ignore. The loss of habitat to agriculture and new roads, the devastation caused by invasive species, the toxic effects of pesticides and the decimation of seabird food supply by longline fishing are all playing their part in the destruction. Meanwhile, almost a third of the world’s parrot species face extinction because of the high demand for them as pets.
Of the 168 species of native birds in New Zealand, only 20% are in good shape. One in every three, the then Parliamentary Commissioner for the Environment Jan Wright wrote in her 2017 report, “Taonga of an Island Nation”, “is not far off from following the moa and many others into extinction. The situation is desperate.”
Endemic birds, long adapted to the New Zealand environment before the arrival of humans and predators, are in most difficulty, Wright wrote. Three – pīwakawaka (fantail), tūī and the riroriro (grey warbler) – have increased their ranges over the past few decades. Of the rest, 13% are doing okay, but 45% are “in serious trouble”..
In her report, Wright identifies the need to increase the genetic diversity of threatened species. Restoring populations of endangered bird species on islands and within fenced sanctuaries protects them from predators, but it also reduces genetic diversity, leaving small populations vulnerable to the impact of disease and habitat degradation. Despite the laudable efforts put into kākāpō and kōkako, for example, isolated bird populations can become inbred and struggle to produce healthy chicks. Bandit, a kōkako on the Tiritiri Matangi island sanctuary in the Hauraki Gulf, she writes, is consorting with his grandmother: “This may be a happy relationship, but it is unlikely to be a healthy one. We must guard against our birds drifting to the shallow end of the gene pool.”
Source:; Noted, 31 July 2018
https://www.noted.co.nz/currently/environment/decline-in-birds-worldwid…
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