A rehabilitated animal always goes back to the exact same spot where it came from, right? Well, no – not always, but usually that’s what happens. As licensed rehabilitators, we are entrusted with providing each animal its best chance at survival after treatment, not only because we care about their health and welfare afterwards, but also because our team has given an incredible amount of time, effort, and resources to return them back to their home.

Sometimes a release occurs exactly at the point of rescue, such as at a home where it was found. Other times, it’s close to that site, such as within a 2-mile radius, and other times it happens far away because their species is migratory and has already left the area. There are so many factors to consider when releasing a patient from rehabilitation that it can be overwhelming to think about, but it helps to break it down to the most important criteria known for that species. A few of those considerations are listed below with questions we often ask:

1. Timing of release
   1. What time of year is it? Is it spring, summer, fall, or winter?
      1. Can the animal withstand local temperatures? Is it fully furred, feathered, or scaled?
      2. Do they hibernate or brumate, or are they active year-round?
   2. Is the species migratory or sedentary?
      1. Where do they go? Are they long-distanced, semi-partial, nomadic, or accidental migrants?
   3. When do they make pair bonds or reproduce?
      1. Are they territorial? Who builds the nest or picks the site?
      2. Are they monogamous or polygamous?
   4. Is their primary food source available year-round or seasonally?
      1. Do they eat live prey, vegetation, or a mix of both?
2. Age of the animal
   1. Has it displayed natural species behaviors throughout development?
      1. Does it have a healthy fear around humans?
      2. Can it find and obtain its own food?
   2. When do juveniles of that same species disperse naturally?
      1. Do they stay with their parents through the fall and winter?
      2. Are they a bird that flocks together in larger groups during migration?
3. Release site location
   1. Do you have permission to release the animal? Are you releasing on private or public land?
   2. Is there active hunting that occurs on the property?
      1. Is there a hunting season for that species, and when is it?
   3. What are the environmental conditions like?
      1. How healthy is the site? Is there concern for toxicity or contamination?
4. Habitat specialist or generalist?
   1. Is it a species that relies on one type of food source or habitat type to survive?
   2. Will a habitat generalist conduct risky activities?
      1. Was it admitted due to “nuisance” behaviors, such as relying on food from refuse?
5. Risks from potential local activities
   1. Was the animal admitted due to injuries related to human causes?
      1. Was it shot, trapped, or harassed in the area previously?
6. Natural history
   1. What do we know from the current body of knowledge or biological research?

For example, habitat specialists like Long-eared Owl #24-0037, rehabilitated and released early this year, are considered a species of special concern in the state of Wisconsin. This is largely due to loss of trees used for nesting and breeding success, specifically, older growth conifer plantations and deciduous forest. If this bird was admitted in the middle of the breeding season, it would be important to get that individual back to the exact location where it was found in case it had already established a territory, found a mate, or started nesting.

Another decision rehabilitators make is whether or not to provide supplemental food for released animals, either in the short-term or long-term depending on the species. Tree squirrels spend time all summer and fall stocking up food, such as burying nuts in specific locations, so they can return to a cache when natural food supplies are low. Winter isn’t easy for most animals in our region because of snow and ice. Finding food takes time and energy that some individuals may not be equipped to handle. Young animals are especially at risk to starvation during their first winter if they haven’t had enough time to prepare or if they’re out-competed by more experienced adults. They also may be reliant on foods produced in cyclic patterns, like boom and bust crops of acorns or successes versus failures in populations of prey eaten by carnivores (e.g., mice, voles, or rabbits).

At DCHS’s Wildlife Center, rehabilitators offer extended time for young animals to practice finding and obtaining natural foods in our outdoor enclosures, or learning to hunt, until specific criteria have been passed and physical and developmental benchmarks are met. Juveniles of some species, like Eastern gray squirrels, are usually selected for a “soft release” process, meaning people will visit the release site for a pre-determined period of time to continue feeding the animals until spring arrives. Last month, Werndli Apprentices Ashton Whitaker and Emelia Rogers, installed a squirrel box for a group of five individuals on private land in collaboration with members of the Werndli Cheritable Trust. There, food will continue to be supplied and there was plenty of suitable habitat for them to use.

In contrast, our single Red-eyed Vireo #24-2502 was released at the same location with no intention to supplement food. Vireos eat a wide variety of insects, gleaning things like spiders and flying bugs off of the leaves of trees. It took months of collecting live insects from the “bug catcher” every day, and thanks to help from our songbird caretaking volunteers, the vireo had weeks of practice catching and eating natural prey items. While we never know for sure how each individual will fare, this vireo was federally banded and showed full independence by the time of release. For us, as long as an animal has the ability to maintain adequate body weights, fat storage, and fitness, then they are selected for “hard release” with no additional human intervention. Werndli Apprentice Emelia Rogers recalls the moment the bird came flying out of the transport carrier, saying, “It filled my heart with joy that the vireo flew up to a branch and immediately started eating bugs!” This bird was released south of its original rescue location in order to give them a head start for migration, knowing that food was plentiful in the meantime.

There are pros and cons in choosing either type of release. For soft releases, we worry about animals having over-dependence on humans, so we encourage feeding only to occur as needed. For hard releases, we worry about the animals’ ability to find enough food after release when availability is low. So, we time it as best as possible alongside food availability, weather and temperature conditions, age of the animal and time of dispersal, and habitat preferences in addition to using the criteria above to guide our decisions.

While the considerations listed above are important to evaluate when an animal is ready for release, the most important factors are really their health and fitness. Did they recover from their original injuries? If they sustained ocular trauma, can they still see well enough to fly, hunt, dig, swim, and find food? If they lost feathers, will they molt them back in time for migration? Do we know what they’ll do as soon as they’re free? Turtles will travel hundreds of miles to get back to the watershed where they were born, traversing dangerous landscapes and risking their lives to be hit by cars or being predated upon in the process – so what’s the best choice? Get them back to the place where they imprinted on.

If a bird has a wing hike or a droop that’s been persistent from the start, can they sustain flight long enough to travel long-distances? Injuries can be chronic, such as when we see over-grown teeth or jaw and beak malocclusions, and that could negatively affect an animal for the rest of their lives if left un-treated.

While short-term solutions may be achievable, rehabilitators need to look to the future for each animal and consider their welfare after they’ve been left to fend for themselves. Our goal is to reduce pain and suffering and offer best chances for survival. That’s our responsibility, as written in the code of ethics when we’re licensed.

Jackie Sandberg is the Wildlife Program Manager at DCHS’s Wildlife Center.