自1970年以来，北美已经有近30亿只鸟类消失

自1970年以来，北美已经有近30亿只鸟类消失

If your backyard bird feeder seems a little less popular these days, it's not your imagination.

如果你的后院喂鸟器现在看起来不那么受欢迎，那不是你的想象。

Grassland birds like meadowlarks were particularly affected over the past half-century. (Photo: Jack Dean III/Shutterstock)

The number of birds in the U.S. and Canada has plummeted over the past 50 years, dropping by 29%, according to a study published in the journal Science. That's an overall decline of 2.9 billion birds since 1970.

发表在《科学》(Science)杂志上的一项研究显示，美国和加拿大的鸟类数量在过去50年中大幅下降，下降了29%。自1970年以来，鸟类总数下降了29亿。

The study found there were large losses for every type of bird, from songbirds to those that migrate long distances.

研究发现，从鸣禽到长距离迁徙的鸟类，每一种鸟类都有很大的损失。

For the analysis, researchers included citizen scientist data from information collections such as the North American Breeding Bird Survey and the Audubon Christmas Bird Count. They also used data from 143 weather radar stations to look for declines in migratory bird populations. Additionally, they studied 50 years of data collected from on-the-ground monitoring.

为了进行分析，研究人员收集了来自北美种鸟调查和奥杜邦圣诞鸟类统计等信息收集机构的公民科学家数据。他们还利用143个气象雷达站的数据来寻找候鸟数量下降的情况。此外，他们还研究了50年来从地面监测中收集的数据。

Grassland birds, such as meadowlarks and sparrows, were particularly affected. They experienced a 53% drop in population — more than 720 million birds — since 1970. So many of these birds have likely disappeared due to modern agriculture and development, as well as pesticide use.

草原鸟类，如草地云雀和麻雀，受到的影响尤为严重。自1970年以来，它们的数量下降了53%——超过7.2亿只。由于现代农业和发展，以及杀虫剂的使用，这些鸟类中的许多可能已经消失了。

Shorebirds were also hard hit because of their sensitive coastal habitats. Their populations were already "dangerously low," researchers said, but they've since lost more than one-third of their numbers.

滨鸟也因其敏感的沿海栖息地而遭受重创。研究人员说，它们的数量已经“低得危险”，但自那以后，它们的数量减少了三分之一以上。

The researchers tracked spring migration using radar in the night skies. They found that in just the past decade, it dropped by 14%.

研究人员利用夜空中的雷达跟踪春季迁徙。他们发现，就在过去的十年里，这个数字下降了14%。

"It's imperative to address immediate and ongoing threats, both because the domino effects can lead to the decay of ecosystems that humans depend on for our own health and livelihoods — and because people all over the world cherish birds in their own right. Can you imagine a world without birdsong?"

“我们必须应对迫在眉睫的和持续不断的威胁，这既是因为多米诺骨牌效应可能导致人类赖以生存和健康的生态系统的衰退，也是因为全世界的人们都以自己的方式珍惜鸟类。你能想象一个没有鸟鸣的世界吗?”

Success stories

成功的故事

Swans and other waterfowl have recovered due to conservation efforts and wetland protection. (Photo: Phil Wood [CC BY-ND 2.0]/Flickr)

It wasn't all bad news, as researchers found a few promising bright spots.

这并不全是坏消息，研究人员发现了一些有希望的亮点。

They said waterfowl, like ducks, geese and swans, have made a "remarkable recovery" over the past 50 years. Researchers credit conservation efforts made by hunters, as well as government funding for wetland protection and restoration.

他们说水禽，像鸭子、鹅和天鹅一样，在过去的50年里已经有了“显著的恢复”。研究人员将此归功于猎人为保护湿地所做的努力，以及政府为湿地保护和恢复提供的资金。

The study also found that the bald eagle has made an amazing comeback since the 1970s, when the pesticide DDT was banned and endangered species legislation began offering protection to the birds.

该研究还发现，自上世纪70年代杀虫剂DDT被禁止、濒危物种立法开始保护秃鹰以来，秃鹰已经惊人地卷土重来。

"It's a wake-up call that we've lost more than a quarter of our birds in the U.S. and Canada," said coauthor Adam Smith from Environment and Climate Change Canada.

“这是一个警钟，在美国和加拿大我们已经失去了超过四分之一的鸟类，”来自加拿大环境和气候变化的共同作者亚当·史密斯说。

"But the crisis reaches far beyond our individual borders. Many of the birds that breed in Canadian backyards migrate through or spend the winter in the U.S. and places farther south — from Mexico and the Caribbean to Central and South America. What our birds need now is an historic, hemispheric effort that unites people and organizations with one common goal: bringing our birds back."

但是，这场危机远远超出了我们各国的边界。许多在加拿大后院繁殖的鸟类会迁徙到美国或在更远的南部地区过冬——从墨西哥和加勒比海到中美洲和南美洲。我们的鸟类现在需要的是一项历史性的半球努力，它将人类和组织团结在一起，实现一个共同的目标:把我们的鸟类带回地球。”