Figuring out which trails are open and which ones remain closed for the benefit of wildlife can be tricky in the spring. Fear not, mountain bikers, trail runners, dog walkers and hikers. Here’s a comprehensive guide to where you can get your kicks and what’s off limits for a few more weeks.

In general, trail openings follow the snow line. Trails farther downvalley opened first, working upvalley.

In the midvalley, the Glassier trail opened on May 1, creating connections to the extensive Bureau of Land Management network on the Crown, which fully opened on April 16. A rider reported Friday that Glassier was dry and well-packed and that he found the same conditions on the Vasten Trail up to its intersection with Imperial Garden. He didn’t test the gullies on the downhill section of Vasten, which hold moisture longer than the exposed stretches.

The Rio Grande Trail opened May 1 between Rock Bottom Ranch and Catherine Bridge.

The Roaring Fork Mountain Bike Association reported that many of the BLM trails on Carbondale’s Red Hill and outside of New Castle and Rifle also opened on April 16. The Elk Traverse and North Side trails on Red Hill opened on April 16. The Sutey Trail, the northernmost approach to the Red Hill network, is now open to hikers and equestrians but it remains closed to mountain biking until June 1.

The Lorax area BLM routes outside of Carbondale also opened April 16 as did Light Hill and Williams Hill routes.

“The season is just getting started and we already have some new stuff added,” the mountain bike association reported in its latest newsletter. Jumps were added and shaping was undertaken on Lower Father of Ginormous on the Crown. In South Canyon west of Glenwood Springs, “a kinder and friendlier Alpine Slide loop” was added.

Another wave of trail openings will sweep through the valley on May 16. Those include the Sky Mountain Park Trails of Viewline, Cozyline, Cozy Pony, Airline, Incline, Deadline, Skyline Ridge and Ditchline. The Rim Trail North and Seven Star Trail outside of Snowmass Village also open May 16.

Upper Coal Camp Trail in South Canyon opens on May 16.

Many of the trails that remain closed beyond May 16 are on the White River National Forest. They are closed for all uses to protect elk calving areas.

“The White River National Forest has worked closely with Colorado Parks and Wildlife to identify the most critical calving areas for elk, which are seasonally closed to all uses to reduce disturbance,” the U.S. Forest Service said in a news release this week.

In the Aspen-Sopris Ranger District, the Tom Blake Trail, Sequel Trail and other trails in the Elk Camp and Two Creeks vicinity are closed from April 25 through June 20 for the benefit of wildlife.

The Anaerobic Nightmare Trail is closed from April 25 through June 27.

Government Trail and the Sugar Bowl Trail are closed May 15 through June 27.

“We are seeing an increasing number of closure violations from hikers, dog walkers, and cyclists in areas closed for elk calving each spring as the snow begins to melt and these areas become more accessible,” Natahsa Goedert, wildlife and fish program manager of the White River National Forest, said in a prepared statement. “Please help us protect this incredible wildlife resource by using an alternative area during these seasonal closures.”

Goedert said elk return for calving to the same areas year after year because they provide water, forage and the seclusion necessary to birth and nurse without being startled or disrupted. When people or people and their dogs violate the closures and disturb the elk, it can lead to lower calf survival rates.

“Science shows even one person per day can disrupt the seclusion needed for these life functions,” Goedert said.

In the areas outside of Snowmass Ski Area that remain closed, the Forest Service has several alternatives to suggest for trail users. Alternatives include Highline-Lowline, Sam’s Knob and Alpine Springs trails, West Government Trail and the Elk Camp work roads. In addition, North Rim Trail and the Sky Mountain Park network open May 16. The South Rim Trail is open year round.

The Forest Service is also reminding trail and road users that routes are closed to bicycles from Nov. 23 through May 22. That includes the Smuggler Mountain and Hunter Creek area trails on national forest, the Arbaney-Kittle Trail, the Hay Park area, Basalt Mountain area, Thompson Divide area, Sunlight Mountain and Babbish Gulch and the Forest Hollow Trail.

Colorado Parks and Wildlife is urging outdoor adventurers to balance recreation with conservation. Like the Forest Service, CPW is cautioning people to leave wildlife alone during the critical calving time. Young wildlife should not be approached, even if it appears they are alone. Dogs should be leashed to prevent them from chasing wildlife.

RFMBA noted in its newsletter that it is always possible at this time of year to encounter muddy trails from snowmelt or new precipitation. Its mantra is ride dirt, not mud.

“As always, please help us get the word out that when encountering muddy/snowy/wet trails, turning back is the only option,” the mountain bike association wrote.

A good source for all trails and lands managed by public agencies can be found at www.pitkinoutside.org/ .