Wildlife

Birds

Bird watchers can observe many water birds at the lake. The year 2001 marked the first time in recent years that great blue herons were known to nest by the lake. Other water birds include American white pelicans, western grebes, double-crested cormorants, gulls, Canadian geese, and mallard ducks. Another lake dweller is the beaver.

Bald Eagles

One of the park's most famous residents uses both the lake and the prairie around it. For several years, Standley Lake has been home to a pair of nesting bald eagles. During the summer, the bald eagles can fish in the lake. During the winter, when the lake freezes over, the bald eagles can steal prairie dogs caught by other birds of prey. Some of the other birds of prey, or raptors, seen at the park include Swainson's hawks, prairie falcons, and red-tailed hawks. There are also nesting great horned owls, which are birds of prey of the night.

Prairie Dogs

In the 2,000 acres of open space around the lake, one of the most obvious animals is the prairie dog. Prairie dog towns provide food and shelter for more than 100 other species of animals. Many animals in the park, including the bald eagles, coyotes, red foxes and bullsnakes, eat prairie dogs. Burrowing owls and rabbits live in prairie dog burrows. Other mammals seen in the park include mule deer and fox squirrels.

Mammals

Visitors can spot several different mammal species while visiting the park. Most of the mammals are crepuscular, active at dawn and dusk, but you can often see them during the day. This includes coyotes, bobcats, foxes, eastern cottontails, mule deer, white-tailed deer and American beavers. Mammals such as prairie dogs and fox squirrels are diurnal, which means they are most active during the day. There are several nocturnal animals as well. These animals are only active at night, so visitors most likely will not see them when at the park. This includes striped skunks, racoons, mice, voles and bats.

Reptiles and Amphibians

Reptiles and amphibians are common to see at Standley Lake Regional Park in the early fall, late spring and the summer months. The most common reptile to see are bullsnakes. Bullsnakes are a non-venomous snake that spend most of their time in tall grasses, but can be spotted basking in the sun on the trails. They are the largest snake in Colorado often reaching 6ft in length. Another common snake is the western yellow-bellied racer. They are one of the fastest snake species in the United States! Occasionally, visitors can spot a prairie rattlesnake. These are venomous snakes. They have a heart shaped head and rattle at the end of their tail.  If you see a snake during your visit, please give them space. Western chorus frogs are a common amphibian at Standley Lake. Visitors likely will hear their call before seeing them. They call loudly in the spring and usually throughout the summer months making a "creeeeek!" noise. Their call It is often compared to someone running a finger down the teeth of a comb.

Fish

Standley Lake Regional Park is a popular destination for fishing and is host to a variety of fish species including walleye, bass, and trout. The lake is stocked regularly throughout the summer by Colorado Parks and Wildlife. In addition, the lake supports a variety of other fish. During the summer months, the fishing pier is the best fishing spot, but fishing can be done anywhere on the shore except in areas posted otherwise.

State Fishing Regulations (PDF) are strictly enforced. As part of the City of Westminster's Aquatic Nuisance Species Protection Program, aquatic bait and night fishing are prohibited at Standley Lake Regional Park. Aquatic bait includes minnows, leeches, frogs, crayfish, salamanders, etc. The cleaning of fish is allowed only at the fish cleaning station.

Areas permanently closed to fishing include the dam, all paddle launch ramps and docks with the exception of the ADA-accessible floating fishing pier.