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We make podcasts and newsletters that connect people with the cities they love.

City Cast Denver

Let us help you find Mother Nature in this concrete jungle.

Last month, officials confirmed some long-anticipated bad news: The 

invasive emerald ash borer has finally arrived in Denver

. Since its initial appearance in the U.S. in 2002, the pest has decimated hundreds of 

This pesky wood-boring beetle is native to East Asia, and the havoc it wreaks on ash trees (which account for 1 in 6 trees in Denver) is irreversible. The beetle feeds under the bark of ash trees, cutting off the flow of water and nutrients, causing a slow and gradual death for the tree. It was first found in Colorado 10 years ago in Boulder. 

 “the most destructive and economically costly forest insect to ever invade North America.”

Colorado State University reports that roughly 15% of the state’s trees are ash, with nearly 1.5 million providing shade to metro Denverites. Over the last decade, the beetle has largely taken root in ash trees across north Denver, from Fort Collins to Longmont and Thornton to Arvada.

If your ash tree is infested with these pesky little beetles it may exhibit some of these symptoms:

Sparse leaves or branches in the upper part of the tree

Vertical splits in bark possibly showing S-shaped “tunnels” underneath

Miniature leaves at the tips of branches late in the summer

More telltale EAB signs 🔎

Prevention, Mitigation, and Eradication Measures

A tree can be infested long before it begins to show signs of a health decline — so it’s best to treat it before you even suspect an infestation.

You can also opt to replace your ash tree with something different. 

 should be applied every 2-3 years for the life of the ash tree.

For a more holistic approach, some municipalities have 

strategically deployed tiny, stingless wasps

 to attack the beetles’ larvae. Woodpeckers also feast on borer larvae.

Never transport raw ash wood (often firewood) — the most effective way emerald ash borers spread is by hitching a ride on wood transported by humans.

Learn more 🪲

The invasive pest has officially arrived in Denver.

The Emerald Ash Borer is in Denver

Beware of the Emerald Ash Borer

Get to know the natural side of Denver: the plants, animals, weather and more that make our city unique.

Denver Urban Almanac

Urban Almanac

Have you ever wondered what species the bird in your yard is or whether a mushroom on your local trail is toxic? This weekend, you can get the answers to those questions 

 participate in a community science project called the 

, all by simply sharing photos of the wild animals, plants, and fungi you see around 📸🐿️🍄

Started in 2016 as a competition between San Francisco and Los Angeles, the challenge is now a global event to track biodiversity data in cities across the world. From April 25-28, volunteers can submit photos of local flora and fauna to 

, where observations can be identified and tracked.

Last year, 400 people in the Denver and Boulder area recorded more than 4,500 observations of more than 1,000 species. This year’s goal is to get 600 people to make more than 6,000 observations.

helping Denver scientists measure biodiversity

, download iNaturalist and start snapping pictures!

Start by exploring your local park, backyard, neighborhood green space, or favorite trail, and 

 that you see. Or if you’d prefer to participate with a group, check out one of the 

organized City Nature Challenge events around the metro area

Once you submit a photo in the app, it will suggest possible identifications — or you can label it with what you know about it, whether that’s as specific as “a Columbine” or as general as “flower.” After the photo is shared, other people on the app can help identify the species or confirm a suggested ID.

Photos taken in iNaturalist or uploaded with location data will automatically be submitted to the Denver-Boulder challenge data, but here are some tips on how to optimize your observations!

Try to get as close as possible to whatever animal or plant you’re photographing and make sure the images are in focus. (But be sure to stay safe and give animals space!)

Focus on one species in each photo to help make identification easier.

If possible, get multiple photos and at various angles, so that identifying features can be spotted.

Following the observation phase there will be the identification phase, which runs from April 29 to May 4, where scientists will try to identify as many species in the submitted photos as they can. The results will be 

Get started here!

A guide to finding out how to identify plants and animals, while also helping local scientists track biodiversity.

Identifying the Plants and Wildlife in Your Denver Neighborhood

Identifying the Plants and Wildlife in Your Neighborhood

The National Oceanic and Atmospheric Administration’s Climate Prediction Center recently announced that La Niña is likely to emerge in the next month and last until sometime 

. So, what is La Niña exactly, and how would it affect Colorado weather?

In a nutshell: La Niña is one of two abnormal climate phenomena that affect the temperature of the Pacific Ocean near the equator. Normally, trade winds push warm ocean currents west towards Asia, allowing colder water to rise to the surface near the Americas. During La Niña, those trade winds are stronger than usual. In the United States, this can cause droughts and warmer winters in the southern part of the country, and cooler than usual winters in the north. La Niña can also lead to a more severe hurricane season.

Both El Niño and La Niña occur every two to seven years on average and can last from several months to multiple years. El Niño (when warmer ocean temperatures reverse the direction of trade winds) is more common than La Niña.

a slightly warmer and very snowy winter for Colorado

Statewide effects of La Niña are inconsistent, but it does typically mean less than average snowfall. In Denver, six of the last seven La Niña events 

La Niña is also arriving later than usual (it tends to arrive in late summer) and CPC is predicting a “weak” version of the phenomenon, which makes winter weather predictions even more difficult. Two of the last three late-arriving, weak-to-moderate occurrences of La Niña brought more snow to Colorado, while the latest one (2017-2018) marked one of the state’s driest winters.

So, what does that really mean? In a weak La Niña year, trends suggest that Denver and much of the Front Range will see less than average snowfall, while parts of the Eastern Plains and central Colorado could see more snow than usual — potentially good news for skiers and snowboarders.

Experts also note that climate change is exacerbating the effects of extreme weather, adding that the short-term cooling effects of La Niña do not change the 

. One thing is for use, Denverites will still be making use of our winter gear this coming season.

Experts are predicting a weak La Niña this winter. Here's what that means for Denver and Colorado's snowfall.

What is La Niña and How Does it Affects Colorado?

What is La Niña and How Does It Affect Colorado?

Coloradans have mixed emotions about winter. On the one hand, winter means fresh powder and epic skiing for all, but on the other hand, 

 means cold and worse traffic and road conditions than ever before. No matter which camp you fall in, there is one thing that we can all agree on — winter in Colorado is magical, as demonstrated by such phenomena as these frozen ice waves. Let's take a closer look at the frozen ice waves in Colorado.

 and other parts of Colorado, frozen ice waves are an unbelievable wintertime phenomenon that can be caused by freezing temperatures and strong winds.

How can these two seemingly regular weather occurrences cause such a unique phenomenon? In the case of the iconic Great Lakes, where ice waves are even more common, it happens when freezing temperatures, strong winds, and water combine, which form literal waves of chunky ice.

Is this the case for Colorado's ice waves? According to Meteorologist Greg Hanson, who spoke with 

, the cause for Colorado's waves is more likely melted snowdrifts that re-froze, resulting in these all-natural art-like sculptures.

Do you want to get out and see the incredible ice waves for yourself? There are several places around Colorado where you might catch a glimpse of this must-see occurrence including the Lake of Glass at Rocky Mountain National Park and The Loch in the Glacier Gorge (pictured).

If you are wondering if you will see this phenomenon close to home, you just may, as there is still a lot more winter to be had.

For even more Only in Colorado wintertime fun, check out these 

. And don't forget to take a look at our 

It's magical Colorado wintertime phenomenon.

Where to Experience Colorado's Frozen Ice Waves

These Frozen Ice Waves Are a Colorado Wintertime Phenomenon that You Have to See to Believe

Until serious reintroduction efforts in the 1990s, the endangered black-footed ferret had almost completely disappeared from existence — but over the last two decades, Colorado wildlife officials have played a big part in turning things around. In a major conservation win, CPW biologists reported this month that at least 

two new litters of black-footed ferret kits

 were born in the wild near the southeast town of Lamar, Colorado.

Black-footed ferrets were believed to be entirely extinct until one day in 1981 when a dog in Wyoming brought home a dead one (

). Scientists were able to breed thousands of ferrets from that rediscovered colony, but the survival rate has remained low because of the slim breeding pool. Since then, scientists have 

 with the hopes of broadening the genetic stock.

Colorado’s Part in the Conservation Project

Here in Colorado, the small unincorporated town of Carr (near Fort Collins) is home to The National Black-Footed Ferret Conservation Center (founded in 2001). The Cheyenne Mountain Zoo in Colorado Springs also hosts a breeding facility. And in addition to Lamar, Colorado maintains 

Rocky Mountain Arsenal National Wildlife Refuge

. The ferret kits recently discovered in Lamar are a product of 50 ferrets that were bred in captivity in Carr before being released on a conservation ranch in 2021.

Though more than 10,000 black-footed ferrets have been bred in captivity and re-released across the country over the years, officials estimate only 

. The ferrets are impossibly hard to keep track of after release, but thanks to innovative efforts ranging from brightly lit night cams to pet-chip readers, Colorado officials have — for the first time — nabbed proof of survival and reproduction among the ferrets released in Lamar three years ago.

Black-footed ferrets are an integral part of the food chain, affecting the health and survival of a broad range of animals including golden eagles, foxes, and rattlesnakes. Their survival is also an indicator of the health of the grassland ecosystems they live in.

Black-footed ferrets are the only ferrets native to North America.

Their diet almost exclusively consists of prairie dogs. Prairie dog eradication (from people and plague) has played a major part in the ferret’s decline.

Black-footed ferrets live, eat, and sleep in prairie dog burrows.

The earliest fossil record of the black-footed ferret is from 

are called “jills” and males are called “hobs.”

The endangered black-footed ferret had almost completely disappeared from existence, but in recent years, Colorado has helped turn things around.

How Colorado is Helping Bring Back the Black-Footed Ferret

Right now, Colorado — more specifically, the 

 Colorado town of La Junta — is smack dab in the middle of tarantula mating season, and 

. Despite often being called Colorado’s great annual “tarantula migration,” these little critters aren’t actually 

 anywhere. Rather, thousands of sexually mature male tarantulas leave their burrows for an elaborate mating ritual that includes them “knocking” at female tarantulas’ burrows looking for love, and often ends in the males being eaten by the females. Tarantula mating season typically lasts from late August through early October, with a peak in mid-September.

The Denver Butterfly Pavilion conducts its own in-depth 

tarantula breeding, conservation, and education efforts

. Also returning this month is the limited-time “

” exhibit. Step into the 80-foot “Spider Zone” enclosure to get up-close and personal with dozens of free-roaming spiders representing species from more than 20 different countries!

Right now, Colorado is smack dab in the middle of tarantula mating season, and it’s quite the spectacle.

What is the Colorado Tarantula 'Mate-gration'?

Last month, The Old Farmer’s Almanac released its official weather predictions for the 2024-25 winter season. If the 231-year-old source is to be believed, Colorado is in store for a 

less-than-frigid but still snow-heavy winter

What Is The Old Farmer’s Almanac Anyways?

This annual periodical predicts things like weather forecasts, planting charts, and tide tables for the upcoming year based mostly on historical context and astronomical data. Almanacs like this have been around for centuries and were created to help guide farmers at a time when the success of a harvest could mean life or death.

, The Old Farmer’s Almanac has outlasted and outsold virtually all of its competitors, proudly claiming an average 80% accuracy rate.

More than two centuries ago, the almanac’s founder, Robert B. Thomas, used a forecasting technique based on a 17th century theory from Galileo that relied largely on 

. While sunspots are still configured into today’s methodology, The Old Farmer’s Almanac also utilizes much of the same modern gadgetry used by current-day meteorologists.

With today’s high-tech satellites, weather balloons, and radars, it’s not difficult to obtain a fairly accurate weather forecast five days out. So with data from the National Oceanic and Atmospheric Administration at our fingertips, how is The Old Farmer’s Almanac not only surviving the digital age, but still thriving?

Likely, it’s a mix of usefulness and nostalgia — a lot like looking to a groundhog for a prediction about the end of winter, as Adrienne LaFrance 

. It’s a time-honored tradition “occupying that space somewhere between remembering and predicting,” only now it also offers free online gardening courses, seasonal recipes, and a search bar.

In 1942, a German spy was apprehended with a copy of The Old Farmer’s Almanac in his pocket. The Germans had apparently been attempting to use its US weather forecasts to their advantage.

The first edition was published in 1792 during George Washington’s first term as US president.

The Old Farmer’s Almanac didn’t get its first female editor until 2000 when Janice Stillman came on as editor No. 13. She is responsible for bringing the almanac online.

Colorado's weather forecasts for the 2024-25 winter are in — but can we trust them?

Can We Trust The Old Farmer's Almanac?

What Even Is The Old Farmer's Almanac?

Bees, butterflies, and other critical pollinating insects just got a major upgrade — the tiny-but-might invertebrates are now officially classified as wildlife thanks to 

The wildlife title means that Colorado Parks and Wildlife now has some authority over the management of pollinating insects. Before, Colorado was one of nine states that couldn’t effectively study or protect bees, butterflies, and the like if they weren’t recognized under the federal US Endangered Species Act. Now that they’re technically wildlife, CPW officials can direct its resources to pollinator conservation efforts, including:

Mitigate environmental threats to pollinators and their habitats

In 2022, state lawmakers ordered a comprehensive study of Colorado’s native pollinating insects. 

, which were released earlier this year, confirmed suspicions that the state’s pollinator populations have dropped steeply in recent decades (mostly due to climate change). In addition to sustaining Colorado’s natural landscapes and local ecosystems, the economic value of pollinators for our state’s agricultural industry is estimated to be worth billions of dollars annually.

The new designation allows experts and officials to do some heavy conservation lifting, but even a little help goes a long way. Here are a few ways you can support the effort right from your backyard:

Plant pollinator-friendly plants, including native plants and grasses and nectar- and pollen-rich flowers. (Garden-In-A-Box has 

Leave logs, stumps, and tall grasses as pollinator nesting opportunities

Support and contribute to local beekeepers and pollinator conservation organizations, like the 

A new state law just upped Colorado's conservation game. 

Protecting Colorado's Pollinators Just Got Easier

If you feel like your lawn (and garden and home and personal space) is under invasion by grasshoppers, you’re not alone. They’re bad this year — like 

Yes, The Grasshoppers Are Worse This Year

Local insect experts have confirmed it. Why? This summer’s extreme heat is likely one key factor. Grasshoppers aren’t all that bothered by scorching temperatures like many other bugs. So while fellow creepy crawlies are burrowing deep underground to cooler conditions, grasshoppers get free reign.

While grasshoppers are a key part of the natural ecosystem, they feast on the plants, crops, and hard work of farmers and gardeners. A season like this can absolutely decimate the livelihoods of those in the agricultural industry through damaged crops, delayed harvests, and the cost of mitigation efforts.

That’s tricky — especially because Colorado is home to more than 100 different species of grasshopper that all respond differently to mitigation efforts, making it nearly impossible to broadly target them all. Poisons and insecticides are ill-advised because of the negative impact they can have on other players in the ecosystem, like birds and pollinators. The success of DIY remedies, like spraying garlic solution and pepper oils or dusting cinnamon on your crops, varies widely. Most experts recommend installing row covers and landscape netting, then hoping for the best 🤞

This isn’t the first time Colorado has witnessed an especially nasty grasshopper season. In 1937, Colorado saw a grasshopper plague 

 so bad that the National Guard was called in, armed with flame-throwers and troops of hopper-hungry turkeys. Below is an image of a Colorado Springs storefront at the time 😬

But believe it or not — it could be worse.

Grasshoppers Are Invading Colorado

Yes, The Grasshoppers Are Really Bad This Year

Worse than allergies and bad weather, Colorado summers bring — *gulp* — miller moths 😣 Here’s the 411.

Every spring through summer (roughly May through June) miller moths migrate from the Great Plains west to the mountains in search of nectarous, flowery food. That migration path crosses right over metro Denver, where the moths look for dark, preferably damp, pitstops — aka your patio furniture, car doors, window shutters, and any other tiny crack or crevice that seems cozy.

A nuisance, yes. But they’re completely harmless. (Don’t ask about the time I leapt from a moving vehicle when one popped out of the dashboard vent though!) In fact, moths are a pollinator species as critical to the ecosystem as honeybees and butterflies. Plus, birds, bats, and bears rely on them as a food source. So before you go on a moth-murdering mission, experts urge you to consider the catch-and-release approach.

It’s hard to say. While wet winters mean lusher feeding grounds for moths, it also means the moths will be more evenly spread out. In a drought year, you’ll find moths are more concentrated in damper areas.

Moths are attracted to light. (They use the moon to orient their migration journey.) So keep outdoor lights off when possible, and close your window curtains or blinds at night.

They like to hide in tiny nooks and crannies, so keep a tidy patio. Clutter may as well be a tiny moth motel with a “vacancy” sign.

If you’re trying to lure one out of hiding or scare it into flight, moths are especially reactive to the jingling of keys or the rattle of a tin full of coins.

I would NOT encourage using insecticide. They have little to no effect on moths.