As a nature photographer, I use the metadata on my photo files, which includes date taken, to help me predict when certain events will happen in nature that I would like to photograph.

The bull elk drop their antlers in early March. Those same bulls shed the velvet from the antlers about the third week of August.

The Canada geese goslings hatch the last week of April along the Front Range while they arrive about a month later in Estes Park.

The first mountain bluebirds return to Estes Valley the last week of February and the white-faced ibis usually show up at Lake Estes about the second or third week of May to rest for a few hours before continuing on their migration route.

Nature doesn’t follow a calendar, but it definitely likes to be consistent. The repetitiveness is a result of hours of daylight, warming temperatures, changes in the weather, return of insects for food, and changes in hormonal cycles.

As a master naturalist, I am fascinated by the patterns of nature. As a photographer, I use the information to plan trips, photo outings and tours.

What I never considered is that there might be a term for this study of patterns. Turns out there is; it is phenology.

Merriam-Webster defines phenology as “a branch of science dealing with the relationship between climate and periodic biological phenomena (such as bird migration or plants flowering).”

This type of science happens with every aspect of nature.

Leaves will transform from buds at about the same time each year, with dates changing depending on elevation and latitudes.

Baby elk are born during the same few weeks each year in late May and early June. This timing coincides with the peak growth of vegetation, like grasses and forbs, so their mothers have ample and nutritious food to help produce milk for the young calves.

And wildflowers tend to bloom at the same time each year, with pasque flowers popping open into their fuzzy purple petals throughout April, depending on elevation.

This study of seasonal life-cycle events is important for more than the intrepid nature photographer hoping to capture the best subjects of each season. Phenology has become an important method for studying the impacts of climate change.

If plants green up three or four weeks earlier than usual, it could mean a reduced food supply for grazing animals that rely on the forage at specific times to help raise their young. If wildflowers bloom early, the butterflies, bees and other insects that pollinate them may not yet be in the area.

As part of ongoing research within the National Park System, biologists, ecologists and other scientists are studying phenology to determine how it serves as a critical indicator of ecosystem responses to environmental changes.

Within Rocky Mountain National Park, citizen scientists can help document seasonal changes at Lily Lake. Through the Lily Lake Phenology Walk, people enjoying a walk around Lily Lake can also take measurements and record data about what they see at seven observation points along the three-quarter-mile walk.

The hope of the park is to answer questions about changes in phenology and how environmental changes may be impacting wildlife and plants. Some of the questions the park scientists hope to answer include:

1. Has there been a shift in phenology in different plant species at Rocky Mountain National Park?

2. Has there been a shift in the timing of breeding vocalizations of birds and frogs?

3. Has there been a shift in the time snow is present on the ground at different elevations?

For example, were elk, moose and tiger salamanders spotted at the lake? Were ducks spotted swimming in the water?

Did a walk around the lake reveal blooming catkins or leaves changing into fall colors? Are the limber pine trees releasing pollen?

The scientists would also like to know about snow in the area. How much snow was observed on Longs Peak? Was there snow on the trail?

With this data, park managers can evaluate the impacts of climate change and make informed management decisions.

This type of data can be collected in any natural environment — from your backyard to annual destinations far from Colorado — to make your own personal observations about when the animals migrate, give birth, go through a mating season and much more.

For more information about the RMNP Lily Lake Phenology Walk project, visit https://www.nps.gov/rlc/continentaldivide/lily-lake-phenology.htm.