Follow the water before you follow the noise
There is a diagnostic step in Denver that people skip, and it is the cheapest one available. Before you think about the attic, walk the property at dusk and find every source of standing or dripping water. The reason is climate. At roughly 14 inches of precipitation a year and average humidity near 52 percent, water is the limiting resource for a mid sized mammal, far more than food. A dripping hose bib, a bubbling fountain, a dog bowl left out, a low spot under a drip line, all of it turns a yard into a scheduled stop. Animals that stop nightly eventually study the building. That is the sequence: water brings them close, cold moves them in. This is also why prevention here outperforms prevention in wetter cities. In Seattle you cannot take the water away. In Denver you often can, and doing so genuinely changes how many raccoons cross the yard. So fix the spigot, drain the bird bath after dark and bring the pet dishes in. Then deal with the building, because a raccoon that already knows the address will still test the eave.
What a January call looks like at 5,280 feet
Wildlife companies here get a wave of calls in the coldest weeks and the physics behind it is simple. An animal that was comfortable under a deck all autumn starts losing more heat than it can replace once lows settle near 19F, and it goes looking for something insulated. A house offers three answers. The attic is warmest, a garage ceiling is easiest to reach from a fence, and an uncapped chimney is a straight drop onto a sheltered smoke shelf. Counterintuitively, this is a good time to act. There are no kits in January, so a one way door can finish the removal in a few nights rather than requiring somebody to find a nest by hand. The complication is the roof itself: snow and ice cut the number of days a crew can safely seal an opening at this elevation. The sensible plan is to get the animal out during the cold and book the permanent carpentry for the first clear stretch. Put the repair date on the contract rather than accepting a vague promise about spring, because a hole left open through March invites the next tenant.
Spring changes the method, not just the schedule
From spring into late summer, the only question that matters is whether there are young behind the opening. That answer sets the method, the price and the odds of the job going wrong. The common failure runs like this. A door goes on in early May. The mother is outside when it latches. For the next several nights she works at fascia, siding or a second vent trying to get back, doing fresh damage in the process, and the kits, too small to walk out, do not survive. Recovering them means cutting into the ceiling from the room below. The slower method works. Someone gets into the attic, locates the nest, lifts the young into an insulated box and sets it against the wall at dusk. Female raccoons keep more than one den and normally carry a litter to the backup before morning. When you call around during a Denver spring, ask what happens if there are babies. If the answer is only about traps and doors and never mentions finding the nest, thank them and keep dialing.
The cleanup nobody quotes on the phone
Removal stops the noise. Cleanup is what makes the attic usable again, and in dry air it carries a particular hazard. A den in use for a month leaves a flattened nest bowl, torn duct wrap, and a latrine concentrated in one corner. In Denver's low humidity that material dries hard and turns to dust, and dust is exactly the wrong form for it to take. CDC reports that raccoon roundworm eggs need about two to four weeks after being shed to become infectious, and once they get there ordinary disinfectants will not destroy them. Proper handling means protective gear, bagging the material out intact, treating the deck with heat rather than a sprayer, and restoring insulation to its original depth. This is the specific job not to try with a dust mask and a shop vacuum, since a vacuum turns a contained pile into airborne particles across the whole attic. When the bid arrives, check whether removal, treatment and reinsulation sit inside the quoted number or appear later as extras once the crew is already up there.
Reading two Denver bids side by side
Cover the totals with your hand and compare five things before you look at price. One, how many entry points does each list. A gap here means somebody did not walk the whole roof. Two, what material closes them. Heavy gauge steel mesh screwed into sound framing is a different purchase from trim coil and a tube of caulk. Three, is attic cleanup and insulation replacement inside the price or an option. Four, how many return visits are covered and over what window. Five, what happens if an animal is back inside next month, written down rather than said. Then ask about licensing and about what the company does with each raccoon it catches. A specific answer, even an uncomfortable one, beats a reassuring vague one. With median home values near $590,000 in this market, a few hundred dollars between bids feels real, and it is. The point is to spend that money on the exclusion carpentry rather than saving it now and buying the whole job again after the next freeze and thaw cycle opens the same corner.