Wildlife of Denver – Canton Fish Wildlife Control

Denver’s Wildlife Calendar — A Month-by-Month Guide

Denver’s wildlife doesn’t operate on a human schedule, but it does follow remarkably predictable seasonal patterns. Understanding when different species are most active — and when they’re most likely to cause conflicts with homeowners — allows Denver residents to take preventive action before problems develop. This month-by-month guide covers the species most commonly involved in residential wildlife conflicts across the Denver metro area.

Winter: January Through March

January – February: The quietest months for most wildlife conflicts in Denver, but not entirely dormant. Great horned owls begin nesting in January — the earliest nesting raptor in Denver. Coyotes enter their mating season, and vocalizations (howling and yip-howling) increase dramatically during evening hours. Mule deer are at their lowest elevation, concentrated in Denver’s western suburbs where they browse on ornamental plantings.

March: The first true transition month. Raccoon mating season begins in late February and continues through March, with males ranging widely and sometimes entering structures they wouldn’t normally investigate. Skunks emerge from winter dormancy and begin searching for mates — skunk odor complaints spike across Denver as males spray during territorial disputes. Squirrels begin their first of two annual breeding cycles.

Spring: April Through June

April: Wildlife activity accelerates rapidly. Raccoon females begin selecting denning sites for their spring litters — attics, chimneys, and crawl spaces become targets. Fox vixens give birth in their dens, and fox families become conspicuous in Denver neighborhoods as adults increase foraging activity to feed nursing kits. Migratory songbirds return and begin nest-building on residential structures.

May: Peak conflict month for many species. Raccoon kits are born and mothers become highly defensive of attic den sites. Squirrel spring litters are active in attics. The bat maternity exclusion blackout begins on May 1st, prohibiting bat removal from Denver structures until August 16th. Bird nesting activity is at its highest on residential structures.

June: Baby wildlife is everywhere. Young raccoons begin exploring outside den sites. Fox kits emerge and play visibly near den entrances. Fledgling birds leave nests and appear “abandoned” on the ground — in most cases, parents are nearby and the young should be left alone. Skunk kits begin accompanying their mothers on foraging trips at dusk.

Summer: July Through September

July – August: Wildlife families begin dispersing. Juvenile raccoons start ranging independently from their mothers. Young coyotes explore beyond their natal territories. The bat exclusion window reopens on August 16th — Denver homeowners who discovered bat colonies in spring can now schedule professional exclusion work. Beaver activity on Denver waterways is visible as families maintain and expand their dams and lodges.

September: Fall preparation begins. Squirrels enter their second breeding cycle and become aggressive about claiming attic spaces. Raccoons increase foraging to build winter fat reserves. Mice and rats begin seeking indoor shelter as nighttime temperatures drop — the beginning of rodent infestation season in Denver homes.

Fall: October Through December

October – November: Mule deer rut (breeding season) begins, and deer-vehicle collisions surge across the Denver metro area. Coyotes form winter hunting partnerships and expand their ranging territories. Mice and rat intrusions into Denver homes accelerate as cold weather arrives. This is the ideal time to schedule preventive exclusion work on your home before spring wildlife conflicts begin.

December: Most nuisance wildlife activity decreases. Skunks enter semi-dormancy, emerging only during warm spells. Raccoons reduce activity but do not truly hibernate. Squirrels remain active year-round but are less likely to seek new den sites in mid-winter. December through February is the optimal window for sealing potential wildlife entry points on Denver homes, as most species are less likely to be actively using structures during this period.

Prepare Your Denver Home for the Next Wildlife Season

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Denver’s Growth and the Wildlife Caught in Between

Denver is one of the fastest-growing metropolitan areas in the western United States, and that growth has profound consequences for the wildlife species that have inhabited this landscape for millennia. As new housing developments, commercial centers, and transportation corridors push outward from Denver’s urban core, the natural habitat that supports coyotes, mule deer, foxes, and dozens of other species is being fragmented, compressed, and fundamentally altered.

The result is an accelerating pattern of human-wildlife conflict across Denver’s suburban fringe. Animals that once had adequate space to forage, breed, and migrate without encountering residential neighborhoods are now funneled through increasingly narrow habitat corridors — or forced to adapt to urban living entirely. Understanding this dynamic is essential context for every residential wildlife conflict in the Denver metro area, from raccoons in attics to deer in gardens.

How Habitat Fragmentation Works in the Denver Metro Area

Denver’s development pattern has created a patchwork of habitat islands connected by narrow corridors — primarily creek drainages, railroad rights-of-way, utility easements, and undeveloped open space parcels. These corridors are the lifelines that allow wildlife to move between larger habitat areas for feeding, breeding, and seasonal migration. When a corridor is severed by a new road, development, or fence line, the wildlife populations on either side become isolated — genetically, behaviorally, and in terms of their ability to access resources across the landscape.

The South Platte River and its tributary creeks — Cherry Creek, Bear Creek, Clear Creek, and Sand Creek — form Denver’s most critical wildlife corridor network. These waterways support beaver populations, provide hunting territory for raptors, and serve as travel routes for every major wildlife species in the metro area. Denver’s trail system along these waterways, while excellent for recreation, also concentrates human activity directly within the corridors that wildlife depends on — creating daily conflicts that neither people nor animals would experience if adequate habitat existed elsewhere.

Denver Development Impact on Key Species:

• Mule deer: Winter range has shrunk by an estimated 35% along Denver’s western fringe since 2000
• Coyotes: Territory sizes in urban Denver are 50-75% smaller than rural coyote territories
• Foxes: Increasing competition with coyotes as both species are compressed into smaller areas
• Raptors: Nesting site availability declining as mature trees are removed for development
• Beavers: Water diversions and channelization reduce suitable dam-building sites

What Denver Can Do — And What Homeowners Can Do

At the municipal level, Denver and its surrounding communities are increasingly incorporating wildlife corridor protection into development planning. Open space acquisitions along critical drainages, wildlife-friendly fencing requirements in new developments, and road-crossing structures (underpasses and overpasses) on high-conflict roadways all contribute to maintaining functional connectivity for wildlife across the metro area.

Individual Denver homeowners can contribute by maintaining wildlife-permeable fencing on their properties (gaps at the bottom allow small animals to pass through), reducing outdoor lighting that disrupts nocturnal wildlife movement, and supporting local conservation organizations that acquire and protect critical habitat parcels. When wildlife conflicts do arise — as they inevitably will at the urban-wildland interface — choosing humane exclusion-based solutions over lethal control preserves the individual animals and the populations they belong to. Every species discussed in this guide, from bats to beavers, plays a role in maintaining the ecological health of Denver’s remaining natural areas — and their continued presence is a measure of how well the city manages the balance between growth and conservation.

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