Founded in 1968, the Aspen Center for Environmental Studies (ACES) stands as a nonprofit dedicated to environmental science education. With locations at Hallam Lake, Rock Bottom Ranch, and Catto Center at Toklat, ACES has been a beacon of inspiration, fostering a lifelong commitment to the Earth through innovative programming for all ages. Covering ecological literacy, regenerative agriculture, forest health, land restoration, and environmental leadership, ACES reaches over 140,000 individuals annually. From daily teachings in schools and diverse field programs to adult classes and community events, ACES collaborates with 70 partner organizations, land trusts, public agencies, and nonprofits. The organization plays a vital role in the national environmental awareness agenda, aiming to create a community of environmental stewards for the next 50 years. The vision is to empower individuals to make informed decisions in our ever-complex world, ensuring a sustainable and mindful future.

aspen center for environmental studies (aces)

Colorado is a state located in the western United States, known for its rugged natural beauty and diverse ecosystems. The state has a wide range of landscapes, including the Rocky Mountains, high plains, forests, and deserts, providing habitats for numerous species. Colorado's biodiversity is remarkable, with over 900 species of birds, mammals, reptiles, and amphibians identified. The state is home to 42 state parks and 300 wildlife areas, adding up to 218,564 acres of park lands and 684,252 acres of wildlife landscapes. However, despite its natural richness, Colorado faces environmental challenges, including habitat fragmentation, climate change, and invasive species.

colorado

The Greenback Cutthroat Trout (Oncorhynchus clarki stomias) is a remarkable and endangered fish species native to the cold, clear streams of the South Platte and Arkansas River basins in Colorado, USA. Named for its vibrant greenish hue on its back and distinctive red slash marks below its jaw, this trout is a vital part of its freshwater ecosystem. Sadly, the Greenback Cutthroat Trout has faced a dramatic decline in its population due to overfishing, habitat destruction, and competition with non-native trout species. Conservation efforts, including habitat restoration and controlled fishing, are crucial to protect this unique fish and restore its dwindling populations in its native waters.

greenback cutthroat trout

The Preble's Meadow Jumping Mouse is a small rodent found in Colorado and Wyoming, USA. Rocky Mountain Wild, an environmental organization, is committed to the conservation of this endangered species. Dr. Dan Svingen, a respected biologist, plays a key role in researching and protecting the Preble's Meadow Jumping Mouse. The main threats to this species are habitat loss and degradation due to urbanization and agricultural activities. Rocky Mountain Wild focuses on advocating for habitat preservation, conducting surveys, and promoting land-use practices that benefit the mouse and its ecosystem.

preble's meadow jumping mouse

The Gunnison Sage-Grouse is a unique bird species endemic to southwestern Colorado and southeastern Utah. The Bird Conservancy of the Rockies is working towards conserving the sagebrush habitats and populations of this endangered species. 

Dr. Clait E. Braun is a renowned avian ecologist and one of the leading experts on Gunnison Sage-Grouse. He has conducted extensive research on the species and has been involved in conservation efforts for several decades. 

The primary threats to this species include habitat loss, fragmentation, and degradation due to land development and other human activities. 

gunnison sage-grouse

The Red Knot (Calidris canutus rufa) is an endangered migratory shorebird species. The population of Red Knot has faced declines due to habitat loss, disturbance at stopover sites, and a decrease in food availability caused by overfishing of horseshoe crabs. The estimated remaining population is uncertain, but conservation efforts aim to protect critical stopover habitats, regulate horseshoe crab harvest, and promote sustainable fishing practices.

red knot

The Dakota skipper (Hesperia dacotae) is an endangered butterfly species found in North America. The estimated remaining population is uncertain, but it is believed to be in decline. The primary threats to the Dakota skipper include habitat loss and degradation due to agricultural intensification, urbanization, and invasive species. The conversion of native prairies to croplands has greatly impacted their populations. Conservation efforts involve habitat restoration, protection of remnant prairies, and monitoring to support their recovery.

swift fox

The Black-tailed Prairie Dog (Cynomys ludovicianus) is a rodent species found in the grasslands of North America. The estimated remaining population is unknown but generally decreasing. The main threats to this species include habitat loss, disease outbreaks, and extermination efforts. Conservation efforts involve habitat conservation, management plans, and promoting coexistence with human activities.

black-tailed prairie dog

The Piping Plover (Charadrius melodus) is a small, migratory shorebird found along the Atlantic Coast of North America and the Great Lakes. It is listed as threatened under the Endangered Species Act. The population of Piping Plovers is estimated to be around 8,000 individuals. The species faces numerous threats, including habitat loss due to coastal development, disturbance by human activities, predation by invasive species, and climate change impacts such as sea-level rise and increased storm events.



piping plover

The Black-Footed Ferret (Mustela nigripes) is a slender, elusive mustelid endemic to North American grasslands. Adults measure roughly 46–61 cm in total length, weigh between 645 – 1125 g, and feature yellowish-fur with black mask, feet, and tail tip—a distinctive “bandit” appearance. Once thought extinct, the species was rediscovered in Meeteetse, Wyoming, in the 1980s; all remaining individuals were brought into captivity for a breeding program, making the species a notable conservation success story. Today, approximately 350–400 ferrets exist in the wild across multiple reintroduction sites. Typically living 4–5 years in the wild with much shorter mean survival due to high juvenile mortality, they are strictly dependent on prairie dog colonies—for both food (a ferret kills hundreds of prairie dogs annually) and shelter, residing in their burrows. High threats stem from disease (plague and distemper) and prey loss. Natural predators include badgers, coyotes, and raptors. Despite these challenges, conservation continues via captive breeding, ongoing reintroductions, habitat management, and disease control—efforts crucial to sustaining this rare, emblematic species.

black-footed ferret

The whooping crane (Grus americana) is one of the most endangered bird species in North America. With an estimated population of around 600 individuals, reintroduction projects are now in place and the population is estimated to be increasing. The major threats to whooping cranes include habitat loss, collision with power lines, illegal shooting, and disturbance at breeding sites. Conservation efforts involve habitat protection, captive breeding programs, and public awareness campaigns to ensure their survival.

whooping crane

The New Mexico Meadow Jumping Mouse (Zapus hudsonius luteus) is an endangered small rodent species endemic to New Mexico, USA. Known for its long tail and remarkable ability to leap, this mouse inhabits riparian zones and relies heavily on dense vegetation near water sources. The estimated remaining population is uncertain, but it is believed to be small and declining due to habitat loss and degradation caused by agriculture, grazing, water management practices, and wildfires. Conservation efforts focus on habitat restoration, water management strategies, and population monitoring to ensure their survival.

new mexico meadow jumping mouse

The Colorado Pikeminnow (Ptychocheilus lucius) is an endangered fish species found in the Colorado River basin. The population size is uncertain, but it has significantly declined due to habitat degradation, water management practices, and competition with non-native species. Conservation efforts focus on habitat restoration, water conservation measures, and monitoring of populations.

colorado pikeminnow

The Razorback Sucker (Xyrauchen texanus) is a remarkable fish species native to the Colorado River Basin in the southwestern United States. Recognizable by its distinctive humpbacked appearance and sucker-like mouth, this fish plays a vital role in maintaining freshwater ecosystems. Unfortunately, the Razorback Sucker is facing extinction as a result of a severe decline in its population due to habitat alteration, water diversion, and competition with non-native species. Conservation efforts, including habitat restoration and captive breeding programs, are essential to protect this unique fish and prevent its extinction in its native waters.

razorback sucker

The Humpback Chub (Gila cypha) is an endangered native species of the Colorado River that evolved around 3.5 million years ago and is only found in warm-water canyons of the Colorado River basin. The population size is uncertain, but it has declined significantly due to habitat loss, water management practices, and competition with non-native species. Conservation efforts involve habitat restoration, captive breeding programs, and water conservation measures.

humpback chub

The Bonytail chub (Gila elegans) is one of the most endangered fish species in the United States, native to the Colorado River Basin. It is characterized by a slender, elongated body covered in small, hard, bony plates, and its prominent, downturned mouth. Historically, they inhabited a variety of riverine habitats, including mainstem rivers, tributaries, and backwaters, but their range has significantly declined. Today, the Bonytail chub is facing extinction, considered extirpated in the wild for the most part and the few remaining adults in hatcheries. The main threats to this species include habitat alteration due to dams and water diversions, as well as competition and predation by non-native fish species introduced into their habitat. Conservation efforts are focused on habitat restoration and captive breeding programs aiming to create a self-sustainable population.

bonytail chub

The Lesser Prairie-Chicken (Tympanuchus pallidicinctus) is a unique bird species native to the Southern Great Plains of the United States. Known for its striking appearance and elaborate courtship displays, this grouse-like bird plays a vital role in grassland ecosystems. However, its population has dramatically declined due to habitat loss, primarily caused by agricultural and energy development. Conservation efforts are urgently needed to protect its dwindling habitat, implement sustainable land-use practices, and mitigate the threats it faces.

lesser prairie-chicken​

The Mexican Spotted Owl (Strix occidentalis lucida), is a subspecies of the Spotted Owl found in the southwestern United States and Mexico. Recognizable by its mottled brown plumage and distinctive spotted pattern, this owl is a key indicator species for the health of mature forests in its range. Unfortunately, the Mexican Spotted Owl faces significant threats, including habitat loss due to logging and forest degradation, as well as competition with invasive species. Conservation efforts are essential to protect its forested habitats and ensure its survival.

mexican spotted owl

The Southwestern Willow Flycatcher (Empidonax traillii extimus) is a subspecies of the Willow Flycatcher, native to the southwestern United States and northwestern Mexico. This small, migratory bird is known for its olive-brown plumage and distinct habitat preference for riparian areas, particularly willow and cottonwood forests. Unfortunately, the Southwestern Willow Flycatcher is endangered due to habitat loss caused by water management practices, livestock grazing, and invasive species. Conservation efforts are crucial to protect and restore its habitat and ensure the survival of this imperiled species.

southwestern willow flycatcher

The Western Yellow-Billed Cuckoo (Coccyzus americanus) is a species known for its distinctive yellow bill and striking markings. Native to western North America, this cuckoo prefers riparian habitats along rivers and streams, where it feeds on insects and caterpillars. Unfortunately, the Western Yellow-Billed Cuckoo faces significant habitat loss due to river channelization, agriculture, and urban development.&nbsp;

western yellow-billed cuckoo

The Canadian Lynx (Lynx canadensis) is a wild cat species native to North America, with a range extending from Alaska and Canada to parts of the northern United States. Recognized by its distinctive tufted ears, thick fur, and large paws adapted for traversing snowy terrain, this lynx is perfectly suited to its boreal forest habitat. It primarily preys on snowshoe hares, its main food source. However, the Canadian Lynx faces conservation challenges due to habitat fragmentation and prey population fluctuations. Conservation efforts, including habitat protection and research, are crucial to ensure the survival of this iconic species in its northern wilderness.

canadian lynx

The Eastern Black Rail (Laterallus jamaicensis ssp. jamaicensis) is a diminutive bird known for its secretive behavior and preference for dense marsh vegetation. It is one of the smallest rails in North America and is characterized by its dark plumage and short, rounded wings. Despite its widespread distribution, it is considered rare and elusive due to its secretive nature and habitat preferences. The species faces numerous threats, including habitat fragmentation, altered hydrology, land management, climate change, oil and chemical spills, disease, altered food webs, predation, and human disturbance.

eastern black rail

The Eastern Tiger Salamander (Ambystoma tigrinum) is a charismatic amphibian native to North America, recognized for its distinctively vibrant coloration and unique tiger-like markings. Inhabiting various terrestrial and aquatic ecosystems, these salamanders play a vital role in maintaining ecological balance. Despite their ecological significance, Eastern Tiger Salamanders face multiple threats. Conservation efforts are imperative to address challenges like habitat loss, pollution, and disease, ensuring the long-term survival of this species.

eastern tiger salamander

The Rocky Mountain Bighorn Sheep (Ovis canadensis ssp. canadensis) is an iconic species of wild sheep native to the mountainous regions of North America, particularly the Rocky Mountains. Renowned for its impressive horns, robust physique, and agile climbing abilities, this species plays a vital role in alpine ecosystems as a keystone herbivore. Despite facing extinction due to overhunting and habitat loss, conservation efforts have successfully restored populations in some areas. However, ongoing threats such as disease, habitat fragmentation, and climate change continue to challenge the long-term survival of Rocky Mountain Bighorn Sheep populations.

rocky mountain bighorn sheep

The Bobcat (Lynx rufus) is a solitary and elusive carnivore found across a wide range of habitats throughout North America, from southern Canada to Mexico. Known for its short, bobbed tail and tufted ears, the bobcat is an adaptable predator that plays a vital role in controlling prey populations within its ecosystem. Conservation efforts for bobcats focus on habitat preservation, reducing human-wildlife conflicts, and regulating hunting and trapping practices. Research on bobcat ecology and population dynamics helps inform conservation strategies aimed at ensuring the long-term viability of this iconic North American predator.

bobcat

colorado river squawfish, colorado squafish, colorado squawfish, colorado pikeminnow

The Brown-capped Rosy-Finch is a medium-sized, stocky finch measuring approximately 15 cm in length, with a wingspan of about 30 cm. Its coloration is striking and well-suited to its alpine habitat. Males are adorned with a black crown, cinnamon-brown breast, neck, and lower face, complemented by brown and black streaks on the back. The underparts, tail-coverts, and bend of the wings display deep reddish hues that give the species its "rosy" name. Females share a similar appearance but exhibit slightly duller tones compared to males. Juveniles are typically more subdued, with browner overall plumage and less pronounced markings. This finch is highly adapted to its cold, high-altitude environment, where its plumage provides both camouflage and insulation. During the breeding season, they nest in rocky crevices and cliffs, taking advantage of the rugged terrain for protection from predators and harsh weather. Their diet consists primarily of seeds, which they forage from alpine vegetation, along with insects during the summer months to meet the protein demands of raising their young. Social by nature, they form large flocks during the non-breeding season, often descending to lower elevations where they are known to visit feeders in mountain communities. Despite their resilience, this species' reliance on specialized habitats makes it particularly vulnerable to environmental changes.

brown-capped rosy finch, brown-capped rosy-finch

The Black Rosy-Finch (Leucosticte atrata) is a small passerine bird characterized by its dark plumage and distinctive pink highlights. Adults exhibit blackish-brown feathers on the head, back, and breast, with a gray patch on the back of the head and pinkish hues on the belly, rump, and wings. They have short black legs, a long forked tail, and a conical bill adapted for seed consumption. During the breeding season, they inhabit high-altitude alpine zones above the treeline, nesting in cavities on cliffs and rocky outcrops. Their diet primarily consists of seeds and insects, often foraged from the ground, including snowfields. In winter, they descend to lower elevations, forming flocks that may include other rosy-finch species. Due to their remote habitat and declining population, the Black Rosy-Finch is considered one of the least studied and most range-restricted birds in North America. Conservation efforts focus on monitoring populations, protecting alpine habitats, and mitigating the impacts of climate change to ensure the survival of this unique species.

black rosy finch, black rosy-finch

The Arogos Skipper (Atrytone arogos) is a small butterfly distinguished by its yellow-orange wings with black borders, which are more prominent in females. Measuring a wingspan of 29–37 mm, its hindwings have pale yellow veins that contrast subtly with the darker wing surfaces. This species thrives in grasslands and prairies where it depends on host plants like big and little bluestem grasses for its life cycle. The Arogos Skipper exhibits a univoltine (one generation per year) pattern in the northern parts of its range, while southern populations may produce two generations annually. Adults feed on nectar from wildflowers such as purple vetch and coneflowers, and males establish territories by perching near host plants. Eggs are laid singly on the underside of host plant leaves, and larvae create shelters by binding leaves with silk. Overwintering occurs in the larval stage, with development resuming in spring. This species’ specialized habitat requirements make it highly susceptible to habitat loss and environmental changes, emphasizing the importance of prairie preservation efforts.

brown-rim skipper, arogos skipper

gunnison grouse, gunnison sage grouse, gunnison sage-grouse

colorado grouper, mangrove, sea bass, yellow grouper, sailfin grouper

The Boreal Owl (Aegolius funereus), also known as Tengmalm's Owl in Europe, is a small, nocturnal raptor inhabiting boreal and subalpine forests across North America and Eurasia. Measuring approximately 9 to 12 inches (23–30 cm) in length with a wingspan of about 24 inches (61 cm), this owl is characterized by its brown plumage adorned with white spots on the upperparts and streaked underparts. Its large, round head features a distinctive facial disc with dark borders, bright yellow eyes, and a yellow beak, giving it a perpetually surprised expression. Primarily feeding on small mammals such as voles and mice, the Boreal Owl's breeding success is closely linked to prey availability, which can fluctuate with vole population cycles. It nests in tree cavities, often utilizing old woodpecker holes, and may lay between 4 to 6 eggs per clutch. Due to its nocturnal and secretive nature, much about its behavior remains understudied. Despite its extensive range, localized declines have been observed, particularly in areas where old-growth forests are diminishing. Conservation efforts focusing on preserving mature forest habitats are essential to ensure the continued survival of this enigmatic owl.

boreal owl, tengmalm's owl

Founded in 1968, the Aspen Center for Environmental Studies (ACES) stands as a nonprofit dedicated to environmental science education. With locations at Hall...

Founded in 1968, the Aspen Center for Environmental Studies (ACES) stands as a nonprofit dedicated to environmental science education. With locations at Hallam Lake, Rock Bottom Ranch, and Catto Center at Toklat, ACES has been a beacon of inspiration, fostering a lifelong commitment to the Earth through innovative programming for all ages. Covering ecological literacy, regenerative agriculture, forest health, land restoration, and environmental leadership, ACES reaches over 140,000 individuals annually. From daily teachings in schools and diverse field programs to adult classes and community events, ACES collaborates with 70 partner organizations, land trusts, public agencies, and nonprofits. The organization plays a vital role in the national environmental awareness agenda, aiming to create a community of environmental stewards for the next 50 years. The vision is to empower individuals to make informed decisions in our ever-complex world, ensuring a sustainable and mindful future.

aspen center for environmental studies (ACES)

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