We are fortunate that Rocky Mountain National Park hosts a spectacular array of butterflies. If you are interested in learning more, visitor center book stores carry items that provide easy-to-use information about observing and identifying these winged fauna.
Insects are ectotherms meaning they regulate their temperature using external sources such as solar radiation. So you will not see many butterflies on a cloudy day and probably none on a rainy day. Because mountain environments are relatively cold, you will often see butterflies resting with their wings oriented to maximize solar gain.
Butterflies are tied to plants. As caterpillars, they need specific host plants. Adult butterflies take energy from nectar sources through their proboscis, a sort of straw like device. If you watch carefully through binoculars, and sometimes with the naked eye, you can see the butterfly extend its proboscis to sip flower nectar.
Some butterflies are plant specific in their feeding habits but many are generalists. They search for flowers that suit their size to perch and drink. Butterflies carry pollen between flowers (but not as much as bees). Though butterflies have the advantage of mobility, impacts to their flowering nectar resources affect their population. Drought, for instance, causes a plant to wither and produce little nectar as it attempts to conserve moisture. Changes in land use, overgrazing, or invasive plants can change the plant population on which a butterfly relies.
Females search for the host plant on which to deposit eggs. They use their eyes and plant volatiles for general guidance; plus antennae and feet to taste the plant. Eggs are small, pin-head size, and shaped differently depending on species group. Eggs hatch in five days or longer, depending on weather and season.
Did You Know?
Hummingbirds use spiderwebs to bolster their nests, which are the size of a walnut shell. Hummingbird eggs are the size of a Tic-Tac breath mint.