What Arborists Need to Know About Working With Wildlife

Through my work with DeepRoot, I’ve come to love and appreciate trees – especially urban trees – in a way that I never anticipated, so much so that I recently became a certified arborist. But my greatest love, since I was very little, was for animals. There is an intersection between these two interests, of course: wildlife.

While I spend most of my days at a desk, arborists who work out in the field have a big impact on wildlife, whether they’re aware of it or not. I like to think that people who care about trees probably care about other living things too, yet many arborists may not be aware of some of the basic steps they can take to avoid harming wild animals as they work.

Fall is the best time to prune

Anyone who has watched a nature program knows that spring and summer are some of the most active times for most wildlife. Babies are being born and raised and going out in to the world. For this reason, if at all possible it’s best to avoid tree pruning and trimming in the spring. In the fall, there is much less animal activity.

Most routine pruning can be done at any time of year. If a tree is not a hazard, and your client (and you) and both willing, consider waiting it out until baby creatures have left the nest.

Do a pre-work wildlife survey

In some cases, waiting until the fall to do tree work is not a feasible option. If so, minimize your impact by conducting a pre-work wildlife survey. This doesn’t need to take long, and can be done at the same time that you complete your other prep work prior to beginning a job.

Here’s what David Lee, the former Program Director for the Wildlife Training Institute recommends:

  • Learn about birds in your area – when they nest, where and what their nests look like.
  • Be on the lookout for nesting birds all year-round, not just during the spring nesting season. Nesting birds can be found at any time of year, especially in warmer ‘sunbelt’ climates. Woodpeckers and owls often use nest cavities in dead limbs for shelter in winter.
  • Inspect trees and other vegetation in the work area for bird activity before climbing or trimming. If possible, survey the work area at dawn or dusk when birds are more active, and glass the area with binoculars. Look at all sides of the tree, and make sure you can see the tallest branches. Look for any movement or shapes that do not fit the branch patterns.
  • Listen for vocalizations or alarm calls of birds or other animals as you examine the tree. Talk to neighbors and tree owners to see if they have any additional information about resident animals.
  • Look for signs of animal inhabitants at the base of the tree such as “whitewash” (bird droppings), bat guano, owl pellets, shelled nuts, paw prints, etc.

Your pre-work survey may not yield any clear conclusions, in which case you’ll need to consult a qualified biologist to determine the appropriate next steps. If the work is being done for a utility company, contact someone at the company (they may have their own in house wildlife biologists). Otherwise, call around for a reputable environmental consultant with experience conducting pre-work surveys.

What to do if you find a nest or baby animal

If you find an active nest while you’re working, stop and call a qualified biologist or a local wildlife agency. Do not touch or try to move the nest. Stay 50 feet away from active songbird nests, and 500 feet away from active hawk and owl nests.

If you find a nestling that you believe to be in danger, contact your local wildlife rehabilitation agency. According to the Hungry Owl Project, a volunteer-run group that tries to reduce the need for pesticides and rodenticides by introducing natural predators, removing a nestling from is an absolute last resort and should only be done if the bird is in serious danger. You may see nestlings on the ground during the fledging period, but they are still being cared for by their parents.  If you believe the nestling is in danger from ground predators, you can place a cardboard box over the bird until professional help arrives.


There are 836 different bird species that are currently protected by the Migratory Bird Treaty Act, including “common” birds like ducks, geese, woodpeckers, hawks, owls, herons, cormorants, crows, doves, and many songbirds.

Maybe you don’t care about wildlife (that’s a topic for a separate post). Protecting birds and other wildlife is also a legal issue. According to Lee, most birds “are protected by federal and state laws that can result in hefty fines for harassing or harming birds, their nests, or eggs.” In addition to birds, several species of bats, opossums, raccoons and squirrels also all use trees as their habitat.

If you work with trees, you will necessarily encounter wildlife. I think it stands to follow that working safely and respectfully with wildlife should be an important component of the arborist training program, but it’s entirely the responsibility of the arborist to educate themselves about these important issues. If you want to learn more about safety measures for working with wildlife, visit the Wildlife Training Institute website or consider enrolling in their Certified Wildlife Protector Program (1 CEU).

Images: Gardening in a Minute, Fran 53


  1. Thanks for this post. A good reminder for sure. I’ll be looking into that Certified Wildlife Protector Program. Thanks

  2. Love the post..really nicely written. Going to look into the program also

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