Like canaries in the coal mine, declining bird populations across America’s grasslands are early warning indicators of much bigger ecosystem disruptions that affect us all. The birds are still singing to us, but they are doing so in greatly reduced numbers. They’re telling us that we need to do more, not less, to protect their precious habitats on our farms and ranches.

Over the past four decades, many birds once common in U.S. farmlands have become uncommon. The clear whistles of the Eastern Meadowlark ringing across a pasture are being silenced, as their population has plummeted 70 percent since 1970. The same is true for the diminutive and mysterious Henslow’s Sparrow — a prairie bird whose population may be down as much as 95 percent since the mid-1960s.

Yet, bright spots exist for both species, where local sub-populations are rebounding. In Illinois, recent spring counts of Henslow’s Sparrows are more than 25 times greater than they were in 1985. There is no mystery to these bright spots: The difference has been the farm bill’s Conservation Reserve Program (CRP), which pays landowners an annual per-acre fee to allow cropland to go fallow and then helps with the conversion to grassland. Henslow’s Sparrow counts are highest in Illinois counties with the most reserve program acreage.

The farm bill is not only important in helping our nation’s farmers produce food; it is also the biggest source of conservation incentives for private landowners. In addition to encouraging more grasslands, the incentives include paying some landowners to grow crops or graze cattle in a more sustainable manner. And as is shown in the recently published report “The State of the Birds 2013,” which we and several others helped compile, these conservation incentives work.

Private farmlands provide critical bird habitat, with 80 percent of the populations of 29 vulnerable grassland-breeding bird species distributed across private lands. In the Prairie Pothole Region of the upper Midwest, farm bill CRP lands have produced a 30 percent increase in waterfowl breeding over the past two decades. Out west, the Sage Grouse Initiative has partnered with more than 700 ranchers to improve bird habitat on more than 2 million acres in 11 states, while promoting more nutritious grasses for grazing cattle.

But now farm bill conservation gains are at risk.

Last year, farm bill conservation spending totaled about $5 billion. Now, the House and Senate might not be able to reconcile their divergent versions of the 2013 measure. Even if they do, both have substantially reduced incentives for conservation on farm lands. Sequestration is poised to reduce farm bill-sponsored conservation by $2 billion over the next 10 years, on top of the $3 billion in conservation funding reductions made over the past five years. In the past half-decade alone, the total acreage of grasslands enrolled in the CRP has decreased by 10 million acres (almost a one-third decline) .

The 20 farm bill conservation programs benefit far more than just birds. Many encourage and absorb the costs of transitioning to sustainable agriculture that yields both healthy food and vibrant ecological systems. For example, farm bill CRP lands have resulted in cleaner water, with 124 million pounds of phosphorous and 623 million pounds of nitrogen kept out of our nation’s waterways.

Yet even with 27 million acres enrolled in CRP nationally, our ecosystems are stressed. Record plantings in the Corn Belt are estimated to be more than 97 million acres — the most since 1936, during the Dust Bowl. Perhaps not coincidentally, a dead zone of oxygen-depleted water about the size of Connecticut now exists downstream in the Gulf of Mexico. (At about 5,800 square miles, this dead zone overlaps a vulnerable area still recovering from the massive oil spill several years ago.)

Conservation is not a luxury. The prospect of no 2013 farm bill means that new CRP enrollments would stop, as would those for the similar Grassland Reserve and Wetlands Reserve programs, and longtime federal incentives for farmland conservation would be in serious jeopardy.

Besides birds, some of the biggest fans of farm bill conservation programs are farmers. Periodically, the Agriculture Department earmarks funds for conservation programs to be distributed in various regions around the country. New landowner sign-ups for these typically exceed the allotted funding, often meeting the quotas within days or even hours of their release.

It is essential that Congress pass a responsible farm bill this year, one that retains its historically vital conservation provisions. Without it, the silence of the birds will spread to new pastures and envelop our heartland.