Last spring, I walked through in a section of the Johnson Creek Trail close to where I live just outside Portland, Oregon, in search of a barred owl. I scanned the trees all around me and found nothing until my friend Devon, who had brought me there, pointed to a feathered shape on the ground. The owl held her wings out in a way that let us know she was finishing a snack. We watched her eat until she took flight into a nearby tree, ruffled her feathers, and began hooting.

It was a strange moment. We were marveling at an owl some people wanted to get rid of. I’d recently become aware of a US Fish and Wildlife Service proposal to kill over 400,000 barred owls in the Pacific Northwest over the next 30 years in hopes of saving another owl — the endangered northern spotted owl — from extinction.

While the spotted owl is native to the West Coast, the larger barred owl, an East Coast native, has been making its way westward since the 1900s. The barred owl is a generalist who can live in many habitats, has more young, and can eat more prey types. No wonder it’s outcompeting the spotted owl, who prefers to live in old growth forests, a dwindling habitat. To save one species that is doing so poorly, the thinking goes, we have to harm another that is thriving on a population level.

This is not the first such bargain we’ve made. To boost salmon numbers, the federal government has killed thousands of double crested cormorants and sea lions in the Pacific Northwest. In Hawai’i, a program once tried to kill Galapagos sharks in order to save endangered monk seals who live only near the islands. In the name of conservation, we’ve killed thousands of “invasive” animals: rats, mice, snakes, cats, goats, and horses — often with little outcry. Some animals, it seems, are worth more than others.

But is our best conservation strategy really to assume one species can live only if another dies? In most cases, there’s room enough for everyone if we commit to giving every species what it needs to survive: usually, suitable habitat.

What spotted owls really need isn’t fewer barred owls but more old growth forest.

Monk seals might occasionally get chomped by a Galapagos shark, but the seals became endangered because of coastal development, viruses like toxoplasmosis, which is spread by cats, and frequent entanglement in fishing gear, not because of their natural predators. And while cormorants and sea lions may have figured out that there’s a feast waiting for them near dam fish ladders, salmon would be better served if we removed the dams blocking their runs and restored the health of rivers.

Or take monarch butterflies, which provide a slightly different type of conservation conundrum. For years, people have been trying to prop up the declining numbers of the insects — whose astonishing, multigenerational migration can span a distance of 3,000 miles — by breeding them indoors. Rearing them has become so popular that there are specialty products and online groups devoted to this practice. But organizations like the Xerces Society say that these interventions can increase parasites in wild populations, decrease genetic diversity, and result in less food for migrating monarchs overall. There are fewer monarchs because their habitat and primary food source have been decimated by development. Avoiding pesticides and planting native milkweed may not be as fun as watching a butterfly emerge from a chrysalis in your living room, but it’s actually helpful.

What spotted owls really need isn’t fewer barred owls but more old growth forest, which could take hundreds of years to create. Unfortunately, while the US Department of Agriculture recently said it would stop logging old growth forests, its conservation plans don’t include mature forests that aren’t quite “old growth” yet (but could become such if they’re protected from logging).

Those in favor of killing for conservation projects often note that while the individual barred owl may not appreciate being shot and killed, it won’t make a difference to the species as a whole. Surely, they say, it’s better to do something than to watch yet another species slip out of our grasp. The trouble is: It’s never just a few species that are in trouble.

Today the barred owls and cormorants might be thriving, but without programs that make changes where change is actually needed — at an ecosystem level — they may soon become the very species we need to protect next.