Braking For Wildlife: The Science of Slower Speed Limits

Braking For Wildlife: The Science of Slower Speed Limits

By Kyle Kissock |

Do slower speeds reduce the chance of a wildlife-vehicle collision?

While the short answer is yes, the longer answer is likely a bit more complicated.

In winter, ungulates like mule deer cluster on the low-elevation buttes around town. Driving the posted speed can help reduce your chances of a collision with an animal.

An article in a recent Jackson Hole News and Guide highlighted the research of biologist Corinna Riginos, who was contracted by the Wyoming Department of Transportation to study the effects of reduced nighttime speed limits on wildlife-vehicle collision (WVC) rates on high-speed roadways.

Riginos’s results indicated that site-specific, nightly speed limit reductions from 70 mph to 55 mph failed to decrease WVCs.

The reason? Despite lower posted nightly speed limits (and in some cases increased enforcement) drivers decreased their average vehicle speeds only 3-5 mph.

This decrease in speed was likely not enough to compensate for the fact that vehicles traveling through “high-speed” study sites were moving relatively fast to begin with.

As the vast majority of WVCs occur at night, drivers involved in collisions likely still “outran” their headlights, a phenomenon that becomes increasingly hard to avoid (even for attentive drivers) as vehicle speeds exceed 35 mph.

However, it’s important to note that this study focused on a specific type of road; high-speed, two lane highways, and does not mean that slower speed limits are ineffective at preventing WVCs.

Rigino’s recent study showed that on high-speed roadways (70-80 mph) nighttime speed limit reductions had little effect to reduce wildlife-vehicle collisions

As Riginos points out, research indicates that deer-vehicle collisions in zones with permanent speed limits of 65 mph were over 60% more likely to occur than deer-vehicle collisions in zones with permanent speed limits of 55 mph. In these areas, even a 10 mph decrease made a significant difference.

What about nightly speed limits in Teton County?

Although it does get harder to avoid WVCs at night as you “outrun” your headlights, reducing your vehicle speed still means increased reaction time as a driver.

Currently, ungulates in our valley are residing at low elevations and spending time on or near roadways where travel is easier than wading through the deep winter snow pack.

It’s on these town and county roads, where speed limits are relatively low to begin with, that driver behavior can have an out sized impact on avoiding collisions with wildlife.

For example, reducing your speed from 40 mph 30 mph on Broadway (in the 30 mph posted stretch) likely has more of an impact on collision avoidance than if you were to reduce your speed from 80 mph to 70 mph on, say, Interstate-80.

Moose-Wilson Rd, N. Highway 89 in Grand Teton National Park, and south of town near Rafter J are examples of where recent WVCs have occurred, and where abiding by the speed limit at night (it is the law after all) can truly safe a life.

By modeling good driver behavior, those of us who care deeply about wildlife can set examples for the rest of our community to follow!

Five Species to Nature Map in Wintertime

Five Species to Nature Map in Wintertime

By Kyle Kissock |

What birds come to mind when you think of species that are ‘seasonal residents’ of Jackson Hole?

While you’ll likely consider any number of summertime breeders, Osprey, Mountain Bluebird, or vibrant Yellow Warblers, there are a select few species which expand ranges south into Jackson during winter
These ‘winter residents’ usually depart our valley by springtime for breeding grounds farther north.

This article profiles five of these unique, winter-residents, which Nature Mappers can be on the lookout for now, as the snow flies!

 Northern Shrike (Click for Sightings Map)

Photo Credit: John Breitsch, Creative Commons

The Northern Shrike is a predatory songbird which breeds in polar regions. It expands its range south during the winter, where in Jackson Hole, it replaces the Loggerhead Shrike (a summertime breeder) as the resident Shrike species in the valley. Nature Mapping submissions indicate Northern Shrikes are seldom seen in the valley after the first week of April, which is when this species returns to its northern breeding-grounds. Our FOY (First of Year) Northern Shrike was Nature Mapped on December 16, 2019.

Northern Shrikes are generally solitary and are often spotted perched on shrubs or fences in relatively open country. Nature Mapping observations indicate you should look for them in the willows along Moose-Wilson Road and the Gros Ventre during the winter.

Rough-Legged Hawk (Click for Sightings Map)

Photo Credit: Tom Koerner, USFWS

The Rough-Legged Hawk is a tundra-breeding buteo which migrates as far south as Texas for the winter. Although Nature Mappers report Rough-legged Hawks in Jackson Hole throughout the winter, sightings tend to be more regular in our valley from mid-October to early December, and then again in the spring. This is likely due to the maximum snow cover Jackson Hole receives mid-winter, as deep drifts or thick ice accumulation can prevent Rough-legged Hawks from reaching their subnivean food source (generally rodents) under the snowpack. Teton Valley is a great place to consistently observe Rough-legged Hawks all winter. The FOY sighting for this species was Nature Mapped on November 30, 2019 by Frances Clark. Our data indicates this species begins to depart the valley by mid-March.

A medium-sized hawk with dark brown “shoulder patches,” dark wing tips, and a dark belly, Rough-legged Hawks prefer open country and are seldom found in conifer forests. Search for them on telephone polls near Kelly Warm Springs.

Bohemian Waxwings (Click for Sightings Map)

Photo Credit: Frank Vassen, Creative Commons photo

Bohemian Waxwings are a highly nomadic species; according the Cornell Lab of Ornithology. Unlike most other songbirds, they don’t hold breeding territories and their presence any given year can be sporadic. When they expand their range south in the winter, they travel in large flocks in search of fruiting plants, frequently mixing with American Robins or with Cedar Waxwings, which unlike Bohemian Waxwings breed in Jackson Hole and can be spotted here all year. Bohemian Waxwings are seldom seen in the valley after the first week in April. Nature Mappers are yet to report a Bohemian Waxwing sighting in 2020, however, this species often appears in our valley as early as the first week of November.

Look for a chunky, dark, medium-sized songbird likely traveling in a large flock. To differentiate a Bohemian Waxwing from a Cedar Waxwing, look for white on the wings and diagnostic rust-colored patch under the tail. Search for marauding flocks Bohemian Waxwings in town on Crabapple trees.

Common Redpolls (Click for Sightings Map)

Photo Credit: Creative Commons photo

The Common Redpoll is a great example of what is considered an “irruptive” species, meaning it is not uncommon for it to irregularly expand its range into areas where it isn’t usually found (likely in search of food). Frances Clark reported multiple “irruptions” of Common Redpolls in Jackson in recent years, including 2016.  Although Common Redpolls are rarely Nature Mapped, at least one Nature Mapper has sighted this species in all but one year since 2011. This species has yet to be recorded by nature mappers this winter. Common Redpolls eat small seeds and are especially attracted to thistle and nyjer feeders, so keep your eye out if you have feeders in your yard . . . our Nature Mapping data shows this bird regularly shows up in town and developed areas.

Look for a siskin-like songbird with a puffy red-chest and a bright red-cap, likely in a flock. Any feeder in Jackson Hole could attract a Redpoll during the right conditions.

Snow Bunting (Click for Sightings Map)

Photo Credit: Creative Commons photo

Our Nature Mapping database contains only 13 reports of Snow Buntings dating back to 2010. Like many of our other winter visitors, this species breeds on the tundra of the high Arctic and expands its range south in the winter. Snow buntings occur exclusively in grassland areas, which in our valley are largely inaccessible during the winter. Teton Valley may be the best place to go to encounter this species, but keep your eyes open when you’re driving out to Kelly or on the National Elk Refuge. The most recent Nature Mapping report of a Snow Bunting was submitted by Tim Griffith on March 4, 2018. Nice spot Tim!

Look for a small, white and black songbird with rusty facial markings, likely traveling with multiple individuals.

Special thanks to Bernie McHugh of the Jackson Hole Bird and Nature Club for his help with his article.

What to Nature Map: November – Early December

What to Nature Map: November – Early December

By Lead Nature Mapping Volunteer Frances Clark

Late fall, early winter is a time of adjustment for wildlife, as well as us. The increasing cold and diminishing food in November encourages movement of species. Many warm bodied critters have left the valley, while others stay here. Winter residents must hibernate, or they must balance their energy budget: conserving their energy use by resting in warm, protected locations or adding to their energy stores by moving and finding sufficient food.

Raccoon tracks in the snow from Wilson, Wyoming.

Some small mammals disappear but others are active. Look for any chipmunks, mice, or voles that may still be seeking seeds, fruits, and invertebrates. They will soon hibernate or go into a torpor. Record these stalwart individuals if you see them. Red squirrels stay up and about to defend their cone stashes vociferously. At night skunks and raccoons are roaming for food and then hunker underground or around buildings for warmth. Fox and coyotes are padding along trails and through fields looking for all the above as their main meal. Long- and short-tailed weasels are turning white and also darting about for prey. Have you seen a bear as a last of year (LOY) entry?

Many of the above critters are usually invisible to us; however, with a skim of snow their tracks prove they are here. Some, such as snowshoe hares, are actually best noted in winter. Pull out your winter-tracking field guides, find a 6-12” ruler to measure the footprint size and stride, and determine whose prints cross your path. Under “activity” enter “animal sign: tracks, scat”, under “notes” your ID details. If possible, attach a photograph of the prints with a ruler for scale (a new feature on our data entry form!) to help our biologists verify your entry. It is fun to record the mysterious dramas going on in our neighborhoods and wild places.

Large mammals are shifting venues, too. Watch for elk and deer crossing roads and grazing in pastures. Where are they now? Keep an eye on the buttes to see if the mule deer are coming back to their traditional winter range, or have the summer fires on East Gros Ventre Butte caused them to shift elsewhere? Where are the bison hanging out? Bighorn sheep are coming into the Elk Refuge. Can you record their “territorial” or “breeding” activity in the next few weeks? And moose: are they bunching up at Antelope Flats? What are they eating? They often prefer antelope bitterbrush at this time of year.

Bighorn sheep can currently be spotted on Miller Butte. Photographer Credit: Mark Gocke

Look and listen for birds*. Trumpeter swans are migrating down from Canada, adding numbers to our resident population. Where are they resting/loafing, and which routes are they flying? See if there is a tundra swan mixed in. Which ducks are feeding in open ponds and streams? Remember, some may be in “basic” (e.g.. non-breeding or dull winter) plumage—an ID challenge. Grouse—ruffed and dusky–are in the forests; and nuthatches, juncos, golden-crowned kinglets, and chickadees forage in mixed flocks. The corvid family: ravens, crows, Canada jays, Steller’s jays, and Clark’s nutcrackers often come down from higher elevations and into town when there is deep snow and cold—they are smart. Cooper’s hawks take advantage of birds congregating at bird feeders. Use your binoculars to spy soaring rough-legged hawks or fleeting groups of snow buntings and horned larks in open grasslands. Or find kettles of ravens and eagles over a gut pile.

There is plenty to Nature Map in Jackson Hole these next few weeks. The new entry form makes it easier than ever. Your sightings are extremely important to indicate which wildlife habitats are essential for winter survival. Keep on mapping! Thank you.

*Note: The JH Bird and Nature Club will be hosting a “Winter Bird ID” program December 10th. See the Calendar of Events below for details.

Summary of the 2019 Mountain Bluebird Field Season

Summary of the 2019 Mountain Bluebird Field Season

With the 2019 field season in the books (and Mountain Bluebirds from our nestboxes showing up as far south as Ft. Worth, Texas), November is a great time to cozy up by the fire and reflect on the robust, scientific data gathered during this year’s monitoring program!

This season was our third consecutive year banding Mountain Bluebird nestlings on the National Elk Refuge (NER) with identifiable colored-bands. It also marked our 16th straight year engaging volunteers to help monitor Mountain Bluebird Nestboxes on the NER nestbox trail!


We will likely remember the 2019 field season for its uncommonly cold spring and relatively low rates of bluebird nestling success compared to previous seasons.*

We can report success in banding another “cohort” of nestlings and having 4 banded birds from previous years resighted in Jackson Hole this year.

Takeaways included:

  • Volunteers and JHWF staff successfully monitored 112 nestboxes along the western edge of the NER this nesting season. 
  • The Mountain Bluebird nestbox-occupation rate was only 11% this season. The 89% of nestboxes that were unused by bluebirds were either left unoccupied our utilized by Tree Swallows or occasionally by House Wrens. 
  • JHWF professional bird banders placed identifying colored-bands on 43 nestling bluebirds. This number was down from 72 in 2018 and 85 in 2017; however, as the number of banded birds grows, we expect the number of “resighted” birds to increase reach summer. 
  • Ten (10) adult Mountain Bluebirds which hatched in NER nestboxes have been “resighted” since banding began in 2017. This includes 4 resights made in 2019. Deceased birds account for 2 of the 10 resightings; one banded bird was hit by a car near the National Museum of Wildlife Art while another struck a window near Tribal Trails. 
  • Several bluebird nests were predated (likely by weasels or raccoons) and/or were abandoned in 2019. We now installed safeguards on 25 nest boxes with a history of invasion, which we hope will deter predators in 2020 and beyond! 


Please click here to read the full report on the 2019 Mountain Bluebird Nestbox Monitoring Season. This report includes stories of individual birds, such as the female recently recorded in Texas.

To learn more about our Mountain Bluebird Nestbox Monitoring Project, follow this link.

*It’s possible the prolonged cold snap played a role in reducing the rate of successful nests we saw this year. Further explanation is provided in the report.

Watch for Wildlife Where the Fences End on S. Highway 89

Watch for Wildlife Where the Fences End on S. Highway 89

By Kyle Kissock | Communications Manager

Wildlife-Fencing Project Completed

The Wyoming Department of Transportation (WYDOT) recently completed the installation of “wildlife-fencing” along S. Highway 89 from South Park Loop Road to Munger Mountain Elementary School.

This general stretch of highway is a well-known hotspot for wildlife-vehicle collisions (WVCs), primarily due to the combination of high traffic volume and proximity to high-quality habitat for elk and mule deer, species which both utilize the nearby Snake River corridor.

New “wildlife-fencing” along S. Highway 89 funnels wildlife towards underpasses where they can cross under the road, like this one just north of the waste transfer station.

The goal of the new wildlife-fencing is to keep animals off the road and funnel any would-be highway crossers towards a series of wildlife underpasses.

Drivers can spot these underpasses in three locations: just north of the waste transfer station, under Flat Creek bridge, and under the Snake River bridge (on both sides of the river).

To assist any animal that might wander onto the road and find itself trapped between the parallel fence lines, “jump-outs” have also been constructed along the highway to enable wildlife to safely escape the roadway without the ability to re-enter.

Know the Danger Zones

While the Jackson Hole Wildlife Foundation is optimistic about the new fencing decreasing WVCs within the fenced zone, we’re still asking motorists to expect wildlife on the roadway while traveling on S. Highway 89.  In fact, the possibility exists for a potential increase in animal-crossing activity in certain areas, especially where the wildlife-fencing comes to an end.

Recently completed “wildlife-fencing” runs from South Park Loop Road to Munger Mountain Elementary School on S. Highway 89. While the new fences will help keep animals off the road, drivers should be aware of increased numbers of wildlife on the roadway at the ends of the fences (orange ovals).

This is because when an animal encounters the new fence near its northern or southern limit it will likely follow the new barrier until its first available crossing opportunity.

This opportunity will either be an underpass within the fenced zone, or the end of the wildlife-fence depending on the direction the animal choses to travel.

These new “danger zones” exist near the Munger Mountain Elementary School (southern fence terminus) and the intersection of Highway 89 and South Park Loop Road (northern fence terminus).

For the time being, travelers south of town will notice WYDOT has placed digital message boards at each of these locations to alert drivers of this exact issue.

View showing the full extent of an underpass designed to allow wildlife to safely navigate the movement-barrier formed by S. Highway 89.

Motorists should also be aware that the 3-mile stretch of Highway 89 from South Park Loop Road to High School Road (an existing WVC hotspot area) remains unfenced. It’s possible this stretch may also experience an increase in wildlife road-crossings as animals are inadvertently directed north by the new wildlife-fencing.

With the completion of this S. Highway 89 wildlife-fencing project and the possibility of significant wildlife-crossing funding through the SPET ballot, it’s exciting time for innovative wildlife-crossing solutions here in Teton County.

Let’s just remember to remain vigilant and give wildlife a break where underpasses and wildlife-fences aren’t, especially as we enter migration season in late fall and early winter!


Note: If you are a Nature Mapper, we encourage you to submit sightings of roadkill on S. Highway 89 to help us understand the effects the new wildlife-fencing

Let’s Save a Songbird

Let’s Save a Songbird

By Kyle Kissock, Communications Manager

2.9 billion birds.

Let that number sink in. That’s how many less birds inhabit North American skies, forests, and cityscapes today, than did in 1970.

You probably saw the (now viral) scientific study that was released last month. It exposed an avian population in free-fall in the United States and Canada over the last five decades. Experts are referring to the near 40% decline detailed in its conclusions as a “full-blown crisis.”

A study recently showed North American bird populations undergoing rapid declines. What can we do to help?

In the wake of the study’s release, I found myself feeling a little helpless. I suspect I wasn’t alone. I understand that from a scientific perspective, losing birds has broader implications for ecosystem health. But more personally, identifying the sparrows, nuthatches, and cardinals of my childhood backyard was one of my first authentic connections to the natural world. The arrival of colorful warblers in the springtime, the flocking of chickadees to the feeder during a winter snowstorm. The thought growing up without these backyard birds elicits a visceral reaction; to me, their simple presence still inspires awe and wonder. I believe birds make our world a richer place.

As a community of wildlife-enthusiasts, I think we have rights to be concerned. But a month out from the sobering news of this study, I’m also trying not to feel helpless. It’s true that reversing this trend and effectively combating decline of this magnitude will take intentional, global action. But what’s stopping us from personally working to save one, two, or three birds a year? For example, Nature Mappers report bird strikes on windows nearly every month . . . is there something we can be doing better that can make an immediate impact?

Let’s starting by taking the causes of avian decline case by case. Then, I urge us to consider if there are steps we can take today to lessen our impact on our avian friends. According to the United States Fish and Wildlife Service the top three causes of bird deaths in the United States are as follows:

  1. Cats: 2,400,000,000 bird deaths annually
  2. Collisions with buildings (glass): 599,000,000 annually
  3. Collisions with automobiles: 214,500,000 annually


What can we do? – Consider indoor cats. When young birds leave their nests, there is a period of days when they cannot sufficiently fly to escape predators. These fledglings stand virtually no chance against prowling prides of suburban felines. Many of us have pet cats ourselves. All of us know somebody who owns a cat, or cats. These numbers do not mean we should give up our beloved cats. They do mean that if we’re serious about being a good neighbors to local wildlife, we should be aware of the impacts “outside cats” have on nesting bird populations.


What can we do? – Drive a reasonable speed and pay attention to the road. Do not crash your car trying to avoid a bird. Do remember, the faster you drive, the less time any animal will have to react to avoid being smashed by your vehicle. Not carelessly exceeding the speed limit in known wildlife-habitat is a great way to keep yourself and animals safe!

Window Strikes (The single easiest way to help birds)

What can we do? – Birds collide with windows because they see reflections of sky, vegetation, or sometimes themselves. If you have windows that regularly experience bird strikes, please consider one of several mitigation techniques.

  1. Window decals – These can be purchased on Amazon here as well as from decal-specific sites here or here. Find a decal that works for the aesthetics and functionality of your window. Recommended spacing for decals is small enough that birds can’t fly between them, but anything is better than nothing. Personal note: I had “problem windows” in my apartment before adding a few clear, window decals. My evidence is unscientific, but my problem windows have experienced far less bird strikes over the last year. I wish I had acted sooner. 
  2. Write-on-glass markers – Check out this video to see how to mark your window with glass markers so that they are apparent to birds!
  3. Vertical blinds and or screens – A screen on the outside of a window can minimize reflective potential of the glass. Vertical hanging blinds on the inside of a window can serve the same purpose.

 Click here for more mitigation techniques.

So where does this leave us? Admittedly with a long way to go. But we also know that many people coming together, to make small changes really can result in outsized impacts. As acommunity that pledges to live compatibly with our wild neighbors and reduced human impacts on wildlife, I believe it’s our responsibility to consider everything from moose to Song Sparrows, in the course of our daily lives.

If you find yourself acting to minimize your impacts on birds on the heels of this report, please let me know at I’d love to share your story!

Note: In the past, Nature Mappers have coded mortalities from bird-window strikes as “Accidents” in the NMJH database. To be more specific going forward, the correct coding will be “Serious Injury” with a prompt to make comments in the “Notes” field to record a bird-window strike. 


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