NarrativeBear, 1 year ago (edited 1 year ago)

There was a documentary I watch years ago where they went into great detail into this, as well as the design of these things. Can’t remember where i saw this documentary though.

Anyways, researchers setup cameras trigger by movement and body heat to watch these overpasses and found no evidence of higher predetor active.

They also went into detail about how these things are design with extra width and gentle slopes to make them as “friendly” as possible depending on the specific species that will be migrating in the area, as different wildlife species prefer different types of crossing structures.

For example:

Grizzly bears and wolves

Wary animals like grizzly bears and wolves there is a “learning curve”, it may take up to five years before they feel secure using newly built crossings. Grizzly bears, elk, moose and deer prefer wildlife crossings that are high, wide and short in length, including overpasses

Cougars and black bears

Cougars and black bears prefer long, low and narrow crossings such as underpasses.

Elk

Elk are usually the first large species to use the new crossings, even using some while they are still under construction!

Here are some articles that talk about some of the studies:

wildlife.org/wild-cam-do-predators-ambush-at-unde…

www.nature.com/articles/s41598-020-67340-8