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Three billion North American birds have vanished since 1970
- coldtea 7y ago>Since the 1970s, the continent has lost 3 billion birds, nearly 30% of the total, and even common birds such as sparrows and blackbirds are in decline, U.S. and Canadian researchers report this week online in Science So, at 1970s we had 9 billion birds, and we know have 6 billion birds? I've seen articles that say: "Cats that live in the wild or indoor pets allowed to roam outdoors kill from 1.4 billion to as many as 3.7 billion birds in the continental U.S. each year, says a new study that escalates a decades-old debate over the feline threat to native animals". Compared to that, a drop of 3 billion birds "since the 70s" seem a tiny number, no?
- Arnt 7y agoThat doesn't follow. Birds are generally prey and have a typical prey strategy; they lay lots of eggs and expect few chicks to reach adulthood, while the large majority become food for someone. Sparrows lay about four eggs per year and become >10 years old, for example. You should expect lots of sparrows to be eaten. Otherwise, the number of sparrows would grow by >100% per year. What this study says is that the number of chicks to reach adulthood is below two per hen, sustained for 50 years.
- ColinWright 7y agoDiscussed extensively last week: https://news.ycombinator.com/item?id=21019995 https://news.ycombinator.com/item?id=21019995 https://news.ycombinator.com/item?id=21018916 https://news.ycombinator.com/item?id=21018916
- elorant 7y agoOops, sorry I missed it.