Claire Runge is a postdoctoral scholar at the National Centre for Ecological Analysis & Synthesis (NCEAS) at the University of California, Santa Barbara, previously at the University of Queensland; James Watson is director of science and research with the Wildlife Conservation Society (WCS) and an associate professor at the University of Queensland; Richard Fuller is an associate professor at the University of Queensland. The authors contributed this article to Live Science's Expert Voices: Op-Ed & Insights.

In one of the most amazing wildlife spectacles on the planet, millions of birds migrate each year between their breeding and wintering grounds, undertaking journeys that are remarkable feats of navigation, yet incredibly dangerous.

Migrations can span vast distances, such as the bar-tailed godwit's single flight of nearly 7,000 miles (11,000 kilometers), or the Arctic terns, which over the course of their lifetimes travel the same distance as going to the moon and back — three times. Some of them return year after year to the same location, navigating across a planet now vastly changed by humans.

An arctic tern. (Image credit: Copyright Steve Zack, © WCS)Lost landmarks, lost migrations

Protecting these magical journeys is increasingly challenging in the face of rampant habitat loss around the world. Each year, more and more birds return to former breeding sites only to find concrete, houses, roads and farms. Key stopover sites, where birds rest and refuel on their journey, are increasingly being lost.

It has long been argued that one of the best ways to protect migratory birds is to put aside land in protected areas. Yet in a study published recently in Science, we revealed that more than 90 percent of migratory species are missing adequate protection in one or more of their seasonal ranges.

Bit by bit, the planet is losing the places that migrating birds need to make their annual journeys .

More than half of all migratory birds across the world have declined during the last 30 years. For example, the cerulean warbler is a tiny sky-blue bird that migrates annually from the eastern United States to Colombia and Venezuela. The mature forest this bird relies on at either end of its journey has been largely converted to agriculture and urbanization, and the species has declined by more than 80 percent in the past four decades, according to BirdLife International.

Bar-tailed godwits roosting. (Image credit: Copyright Steve Zack, © WCS)Without protection across their breeding grounds, wintering grounds and the migration corridors in between, birds are highly vulnerable to threats such as vegetation clearing, hunting and pollution. As ecological damage continues to expand across the globe, migratory birds are losing crucial links in the chain of sites on which they rely.

For example, loss of coastal habitats in a small area of the Yellow Sea has driven large declines in millions of migratory shorebirds that migrate between the Arctic and Australia each year.

A white stork. (Image credit: Copyright Steve Zack, © WCS)No single country can solve this

The efforts of any single country to protect migratory birds can be futile if the birds remain unprotected elsewhere along their migratory route. Germany's protected areas adequately protect 98 percent of the migratory bird species within its borders, but fewer than 13 percent of those species have sufficient cover along their entire migration.

This is not a case of wealthy nations losing natural heritage to poor nations. Case in point: In the Western hemisphere, many Central American countries with low gross domestic product (GDP) have sufficient protected areas for more than 75 percent of their migratory species, but these species are less protected in Canada and the United States.

Global cooperation is critical for conserving migratory species. A number of international agreements are in place to protect biodiversity, including specific arrangements for migratory species, but our analyses show there is a long way to go. We found that rather than being located in the best places to connect the gaps for migratory species, the placement of protected areas across the globe is no better than random. International agreements, like the Convention on the Conservation of Migratory Species, have yet to show signs of progress in guiding the placement of protected areas for migratory species.

Safeguarding the world's migratory birds will require much more imaginative use of international mechanisms to create new protected areas and improve the management of those that already exist. Countries will need to develop and strengthen agreements and mechanisms to allow transfer of resources (both in terms of funding and transfer of scientific knowledge and skills) between nations, across flyways.

A bar-tailed godwit. (Image credit: Copyright Steve Zack, © WCS)There is still time

Despite our findings, there is hope. Right now, countries around the world are working to increase the extent of their protected areas to fulfill commitments they made in 2010, when leaders from around the world met in Aichi, Japan, at the 10th Convention on Biological Diversity (CBD) Conference of the Parties, to set conservation-protected-area targets for the next decade. This global push to expand protected areas is our best chance to fill in the gaps for migratory birds and there have been some signs of progress.

The Bahamas recently announced new protected areas spanning more than 7 million acres. This is vital habitat for many migratory birds including the largest congregation of the endangered piping plover outside the United States. Portugal recently announced protection of key seabird habitat, a vital step in conserving the critically endangered Balearic shearwater, Europe's rarest seabird. Nations need to make sure future protected areas are established in the right places to fill in the gaps we have discovered for migratory birds.

If you're a topical expert — researcher, business leader, author or innovator — and would like to contribute an op-ed piece, email us here. However, much more remains to be done. Nations must (i) create new protected areas and locate them at the most important sites for migratory birds, (ii) improve the management of those protected areas that already exist, and (iii) coordinate conservation actions across international borders to maximize efforts.

Governments have already made substantial commitments to increase the extent of protected areas by 2020 through the Convention on Biological Diversity’s Aichi Targets. They must fulfill these promises and ensure that they do so in the most effective ways for conserving species. Increased international cooperation is essential, as is strategic science that can provide information on what places are "bottlenecks" for individual migrant species.

Without urgent action to strengthen coordination between countries, many migratory species will continue to dramatically decline and the incredible migratory journeys that have sustained fantastically evolved bird populations and amazed people for generations could be lost forever.

Follow all of the Expert Voices issues and debates — and become part of the discussion — on ;Facebook, Twitter and Google+. The views expressed are those of the author and do not necessarily reflect the views of the publisher. This version of the article was originally published on Live Science.