Despite a decline of 99% in the past 40 years, western monarch butterflies have been denied endangered species listing.

Fewer than 2,000 western monarchs have been counted in California this autumn, but in a long-awaited decision, the United States government recommends not designating them a threatened species. As an iconic and beloved pollinator facing extinction, the monarch cannot wait.

Data from the Western Monarch Thanksgiving Count, led by The Xerces Society, shows the population has fallen below 10,000 for the first time, compared with millions in the 1980s and 300,000 just five years ago.

Dan Hoare, Director of Conservation at UK wildlife charity Butterfly Conservation said: "The Western Monarch population is collapsing, with numbers on its California wintering grounds at a record low. Recovering this species will require habitat restoration efforts at a continental scale and reduce habitat loss, agricultural intensification and pesticide use that is driving this species towards extinction. The Monarch butterfly has undergone huge declines and fully warrants protection under the endangered species act. At a time when the world is waking up to devastating declines of insects across the globe, weakening the legislation that protects them is a disaster that undermines urgently needed conservation efforts.

"This is a species that even a few years ago was passing through the western US in its millions. We know from the success of our conservation work for endangered butterfly and moth species in the UK that these declines are not inevitable – we can act now to save species before it's too late. Let’s not let the Monarch become the next Passenger Pigeon and follow it to extinction."

Eastern monarchs, famous for their 3,000-mile migration to central Mexico, are also in trouble; their numbers have declined by roughly 80 percent in the past 40 years.

It is not too late to reverse this devastating decline of the natural world, but everyone must play their part. Help us save species from extinction.