Editor's note: Peter Doherty, a Nobel Prize-winning immunologist, is the author of "Their Fate is Our Fate: How birds foretell threats to our health and the world." The opinions expressed in this commentary are solely those of the author.
(CNN) -- Birds are a critical part of our ecological system. But more than ever, birds are threatened by human pollution and climate change.
We need the birds to eat insects, move seeds and pollen around, transfer nutrients from sea to land, clean up after the mass death of the annual Pacific salmon runs, or when a wild animal falls anywhere in a field or forest.
How could we enjoy spring without the birds flitting busily in our garden or dropping by to check out the flowers in our urban window box? Can you contemplate America without the soaring bald eagle, or even those scavengers like the pigeons and gulls that clean up discarded food scraps on our city streets and waterfronts? How diminished our lives would be without them.
Scavenging eagles and condors need hunters to behave responsibly and bury, or remove, the remains of any shot deer peppered with fragments of lead bullets. Loons, ducks and other water birds will be poisoned by lead bullets and lead fishing sinkers if we allow such objects to drop in their feeding space.
All sea and shore birds, even the puffins and guillemots of the otherwise pristine Aleutians, need us to make sure that no other heavy metals, like mercury and cadmium, are dumped in rivers and make their way across the oceans.
Birds like the terns, knots and shearwaters that migrate between the far north and deep, deep, south of our planet need people everywhere to cease and desist from filling in their wetland fuel stops and rest stations, and from constructing golfing resorts and factories in their feeding and breeding grounds.
Seabirds are among the most endangered vertebrate species on the planet, with the International Union for Conservation of Nature classifying 97 species as globally threatened, and 17 in the highest category of critically threatened. Of greatest concern are the pelicans of the southern oceans and the spectacular, but slow-breeding albatross.
Plastic bags must be eliminated from natural environments so sea and shore birds don't mistakenly carry such debris back to feed their chicks, with invariably lethal consequences. The albatross, cormorants and herons need us to stop over-fishing and compromising their normal food supply.
The pelicans, penguins and all the birds that inhabit, or visit, our coastlines need us to ensure that we do not dump oil into gulfs and bays, or release so much carbon dioxide into the atmosphere that the oceans turn acidic and we lose the mussels and oysters, the mass of calcareous plankton that feeds so many creatures, and the coral reefs that nurture enormous numbers of edible species.
We must act now to stop the process of global warming so that non-migratory bird species do not die from heat exhaustion on what were safe mountaintop habitats. Any pregnant mammal can look for a cooler spot, but birds can't easily move their already laid eggs when air temperatures suddenly rise to the point where embryonic death is inevitable. Hotter environments also lead to mosquito-borne pathogens, such as the West Nile virus that kills corvids (like the yellow-billed magpies), horses and people.
The birds need us to measure, observe and count them so we know what is happening and have data to use against the deliberately ignorant, the infinitely greedy, corrupt and stupid who are poisoning our planet and robbing us of our future. There are never enough dollars to pay for monitoring the environment so that we can know what's happening with wildlife.
If you care about our future, then become a citizen scientist. You don't need any training, and if you love being in the natural world, you will enjoy the experience even if you hated high school physics and chemistry.
Help the ornithologists and other researchers by joining the National Audubon Society and participating in its backyard bird count or, if you are still mobile and vigorous, the Christmas bird count. Check out where, for example, you might spend some vacation time participating in catch and release surveys to measure the nutritional status of those magnificent, feathered, long-distance migrants.
All such data is fed back into the e-bird TeraGrid database operated by Cornell University for analysis by trained professionals and, for that matter, by anyone, anywhere in the world who wants to access it. Use social media and any means at your disposal to raise awareness about what's happening with the birds. You might even try to persuade politicians to engage with verifiable reality.
Think about it: We share this small green planet. As they fly, feed and nest, the birds monitor the health of the natural world for us, provided that we, in turn, make the effort to access that key information.
The birds and humans are both large, complex and ultimately vulnerable organisms that inhabit the top of the food chain. At the end of the day, their fate will be our fate.