Scientists have discovered the total bird population in the US and Canada has fallen by almost three billion since 1970.
The study, published in the journal Science, was conducted by scientists and conservationists from seven different institutions and looked at nearly five decades of population data on 529 species of North American birds.
Lead author Ken Rosenberg, from the Cornell Lab of Ornithology and American Bird Conservancy, admitted while scientists knew some bird populations were declining the sheer number of losses was ‘stunning’.
Speaking to IFLScience, he said:
We thought that increases in other species would balance everything out overall. That’s not the case at all.
The research found the population of birds at the start of breeding season in the US and Canada has fallen from just over 10 billion to a little more than seven billion in the last 50 years, meaning the two countries have lost more than one in four birds.
Grasslands species such as western meadowlarks and American sparrows have been the hardest hit with more than 715 million birds lost since 1970, while shorebirds such as green herons have been wiped of one-third of their population numbers.
According to the Cornell Chronicle, Rosenberg commented on what the results may mean, saying:
It’s a strong signal that our human-altered landscapes are losing their ability to support birdlife. And that is an indicator of a coming collapse of the overall environment.
The bulk of the losses weren’t rare species, but rather large declines in common birds. A dozen bird families, including finches, warblers and blackbirds, accounted for 90 per cent of the total loss, IFLScience report.
Ecologist Pete Marra, who worked on the study, spoke to NBC News about the findings.
We can all talk through the stories about there being fewer and fewer birds, but it’s not until you really put the numbers on it that you can really grasp the magnitude of these results.
We’re now seeing common species that have declined, things like red-winged blackbirds and grackles and meadowlarks — species that I grew up with, that were very common when I was a kid. That is the most surprising and most disturbing part.
It’s an empty feeling in your stomach that these same birds that you grew up with just aren’t there anymore.
Mike Parr, president of the American Bird Conservancy and a co-author of the study, described the findings as an ‘indication that nature is unravelling and that ecosystems are highly stressed’.
The researchers said humans are driving the decline through the clearing of land, widespread pesticide use and by allowing domestic cats to roam outdoors.
There were some positive findings in the study, as it was revealed waterfowl have grown in number over the last 50 years thanks to policies such as the 1972 Clean Water Act which have helped conserve wetlands. Bald eagles also thrived after DDT pesticides were banned and legislation was passed to help protect the birds.
Rosenberg has said he is ‘hopeful’ the bird populations could bounce back but there needs to be changes made in order for them to do so.
The researchers agreed lawmakers could help by enacting legislation to conserve federal lands and stop the use of neonicotinoid insecticides, while members of the public can help by keeping cats indoors, eating organic food to help reduce the use of pesticides and taking part in bird surveys.
The decline is truly shocking but it is not too late to save the birds.
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