“Felling a tree is not a take of the bats roosting in it unless the tree is felled for the purpose of killing or capturing them.”
This is the example used by U.S. Fish and Wildlife Service Director Brian Nesvik in a September 14, 2026 memo directing Service personnel to adopt a radically narrower interpretation of what constitutes an unlawful “take” under the Endangered Species Act. This matters because a “take” is one of the most important concepts of the entire Endangered Species Act. The memo doesn’t merely tweak an obscure regulatory definition. It potentially changes the circumstances under which killing or injuring a threatened or endangered animal is legally allowed and this is a very big deal.
What exactly is a “take”
The ESA’s definition is surprisingly straightforward. Section 3 defines “take” as:
“to harass, harm, pursue, hunt, shoot, wound, kill, trap, capture, or collect”
or to attempt to do any of those things.
For decades, the Services’ regulations gave particular meaning to one of those words: harm. The former regulatory definition included significant habitat modification or degradation when it actually killed or injured listed wildlife by significantly impairing essential behavioral patterns, including breeding, feeding or sheltering. That definition had been part of the federal regulatory framework for roughly half a century.
In other words, the ESA did not have to wait until somebody stood over an endangered animal with a rifle. If you destroyed the habitat that an endangered animal needed to survive (and that habitat destruction actually caused death or injury) that could constitute take.
This is important because endangered species are generally not endangered because somebody is deliberately hunting every last individual. They are often endangered because animals die as the result of what somebody did something to their environment, rather than what somebody did to the animals themselves.
The administration already removed the regulatory definition of “harm”
This story actually began before the September memo. In July, FWS and NOAA’s National Marine Fisheries Service finalized a rule rescinding their regulatory definitions of “harm.” The rule became effective September 14. The agencies did not replace those definitions with a new regulatory definition. That was already consequential. The former definition explicitly connected habitat destruction to take when habitat modification actually killed or injured listed wildlife. Removing that definition opened the door to a narrower interpretation and the September 14 memo walks through that door…and keeps keeps walking.
The new interpretation of “take”
The memo essentially instructs the Service to treat imperiled animals and plants as protected from killing only when they are specifically targeted. That is a massive shift in policy that has profound implications for conservation.
For example, to circle to the example at the beginning, imagine an endangered bat colony occupying a forest. A timber company cuts down the trees and the bats die. Under the traditional definition and interpretation of “take”, there is a straightforward question:
Did the habitat destruction actually kill or injure protected wildlife?
Hopwever, under the new interpretation, another question comes first:
Was the tree cut down for the purpose of killing the bats?
If the answer is no, the tree cutting isn’t “take”. Even if everyone knew the bats were in the tree and knew that cutting down the trees would kill them.
What about whales?
The memo provides another hypothetical Suppose a vessel accidentally strikes an endangered whale and the whale dies. The vessel operator knew a large number of whales were present, and there was a high risk of hitting one. Perhaps the operator even knew that they were travelling at a speed where striking a whale would be more likely to kill it.
Under the memo’s new interpretation unless the operator specifically aimed their vessel at the whale, it is not “take” the whale. That is an enormous change in the practical meaning of the word.
Why this is a big deal
In the Endangered Species Act Section 9 prohibits unauthorized take of endangered wildlife. Section 10 provides a mechanism for authorizing incidental take associated with otherwise lawful activities.
The phrase “incidental take” is extremely important. Congress explicitly created a mechanism for situations in which an otherwise lawful activity would result in take even though killing or injuring the species was not the purpose of the activity. Section 10 allows the Secretary to issue permits for such incidental take when statutory requirements are met, including minimizing and mitigating impacts. This allows conservation managers to identify the impact, quantify it, minimize it, mitigate it, monitor it and impose conditions.
However, the new interpretation potentially removes a large category of impacts before you ever get to discussing permits and mitigation measures. If an activity doesn’t constitute take in the first place: you can’t issue an incidental take permit; you can’t impose limitations or mitigation measures; and there’s no reason for the developer, fishery, or industry to seek authorization for the animals they may kill. That is potentially a much bigger change than simply redefining a word.
The habitat problem
This is perhaps the biggest conservation consequence. We sometimes talk about endangered species as though the animal itself is the thing being protected.
But an endangered animal needs habitat to survive. The ESA’s prohibition on take has, therefore, historically been one of the mechanisms by which habitat destruction could become a species-protection issue. That is why the distinction between “killing an endangered animal” and “doing something that predictably kills endangered animals” matters so much. The second category is where conservation law has traditionally had to operate.
For decades, the possibility of incidental take has encouraged landowners, developers, industry and Government agencies to identify endangered species before undertaking potentially destructive activities.
That creates an incentive to ask questions such as
- Where are the animals?
- What will happen to them?
- Can we change the project?
- Can we avoid the sensitive habitat?
- Can we move the timing?
- Can we mitigate the impact?
- Do we need an incidental take permit?
Essentially the big question is: what happens to the wildlife when we do this?
If foreseeable mortality resulting from an activity no longer qualifies as a “take” unless the animal was deliberately targeted, that incentive becomes substantially weaker for a potentially large class of activities. Why spend time designing protections for endangered species if the law doesn’t recognize the resulting mortality from your activity as a “take”?
Back to the bat example Robin
Let’s revisit the memo’s example again. There are endangered bats in a forest. The owner wants to clear the forest. But under the traditional framework, the presence of endangered bats could trigger serious questions about whether the proposed habitat destruction would result in “take”. Under the new interpretation, the critical question becomes whether the owner intended to kill or capture those bats. If the answer is no, the bats’ deaths may not constitute take.
All a timber company has to do is say “I wasn’t trying to kill bats” to get away with cutting down the habitat of a protected species. Even if they new the bats were probably in the tree, and cutting down the tree will probably kill them. Proving deliberate intention to kill the bats is going to be incredibly difficult to prove.
Other countries have recognized this issue. For example, in the UK some wildlife laws were changed from outlawing “deliberate” disturbance or injury (i.e. a “take”), because it was almost impossible to prosecute anyone. The accused just had to say in court that they didn’t mean to kill the protected species, it was an accident, and they could not prosecute. So, they changed the law to ban “reckless” behavior. With this change, if you aren’t following guidelines in a location where the protected species occurs, you are acting recklessly, and can therefore be prosecuted.
The US Government has essentially adopted a rule that may make it impossible to prosecute anyone who kills an endangered species by damaging its habitat. All they have to do is claim that was an accident – even if they did it on purpose.
The Trump administration has discovered that it doesn’t need to repeal the Endangered Species Act to dramatically reduce what it protects. It just has to make it impossible to enforce the law when you kill endangered species by destroying their habitat.
