was that North America held about 72,500 snowy owls, about 30% of which were juveniles. The Canadian population of snowy owls was estimated at 10,000–30,000 (in the 1990s) or even to 50,000–100,000 individuals, perhaps improbably. Within Canada, the population on Banks Island was once claimed at up to 15,000–25,000 in productive years and in Queen Elizabeth Islands at about 932 individuals. Alaska is the only state with breeding snowy owls but has probably quite a bit fewer breeding owls than does Canada. Furthermore, the Partners in Flight and the IUCN estimated that the world population was roughly 200,000–290,000 individuals as recently as the 2000s. However, in the 2010s, it has been discovered that all prior estimates were extremely excessive and that more precise numbers could be estimated with better surveying, phylogeographic data and more insights into the owl's free-wheeling wanderings. It is now believed that there are only 14,000–28,000 mature breeding pairs of snowy owls in the world. During lemming declines, the number of nesting females may drop down to as low as 1,700 worldwide, a dangerously low number, and the number of snowy owls worldwide is less than 10% of what it was once thought to be. Due to the small and rapidly declining population, the snowy was uplisted in 2017 to being a vulnerable species by the IUCN. A 52% decline has been inferred for the North American population since the 1960s with another even more drastic estimate placing the decline from 1970 to 2014 at 64%. Trends are harder to delineate in Scandinavia but a similar downward trend is thought to be occurring. Snowy owls are listed in Appendix II of the Convention on International Trade in Endangered Species (CITES) meaning international trade (including in parts and derivatives) is regulated. Anthropogenic mortality and persecution Of 438 band encounters in the USG banding laboratory, almost all causes of death that could be determined, whether intentional or not, were correlated with human interference. 34.2% or 150 were dead due to unknown causes, 11.9% were shot, 7.1% were hit by automobiles, 5.5% were found dead or injured on highways, 3.9% were collision from towers or wires, 2.7% were in animal traps, 2.1% in airplane birdstrikes, 0.6% were entangled while the remaining 33.3% recovered injured due to assorted or unknown causes. Snowy owls are endangered by heavy airport usage resulting in birdstrikes. Many such collisions are known in Canada and likely