Collecting Phenology Data

Fringed Bleedingheart (Dicentra eximia) in my garden. Photo by Donna L. Long.
Fringed Bleeding-heart (Dicentra eximia) in my garden. Photo by Donna L. Long.


Collecting phenology data helps us to understand the ways of the land we live in. This seasonal information probably fills the pages of your nature journal. All you may need to do is to look at your past nature journal pages in new ways.

When you look over your nature journal, ask yourself these questions.

  • What plants bloomed at the same time?
  • What temperature highs and lows did you record?
  • When the first migrating birds returned, what was in bloom?
  • What was the temperature like when you spotted the season’s first bumble bee?

How to Collect Phenology

Begin by thinking about the animals and plants you notice, anyway.  With me it’s always cardinals, robins and the fruiting of mulberry shrubs. Select subjects of interest and set up a routine for collecting and comparing your observations. The best observations are made from the same location year after year.

Limiting what you collect information on is probably a good idea. Too many things to observe and fatigue and frustration may stop you from observing all together.

Choosing Indicator Plants

Most people choose and indicator plant. An indicator plant is observed throughout the seasons. When it blooms (sets seeds, the leaves change color, etc.) the observer notes what other events are happening at the same time.

Good indicator plants don’t move, such as a tree that stays in one place year after year. The citizen science project has information on choosing plants to observe for their project. The information maybe helpful to you.

The Shadbush in my backyard is my indicator plant. When it blooms in spring (in April) I know shad fish are reentering the Schuylkill River and it is a good time to go fishing. The blooms let me know in about 14 days, the time a spring frost can happen is over. The Pleiades reappear in the sky around this time also.


Weather and Climate

Phenological events, which are easily observed such as buds opening or plants leafing out, can be matched with weather conditions and with other, less easily observed events like the hatching of insect eggs.

Temperature – the daily highs and lows

  • The amount of moisture in the atmosphere – rain, snow, fog, dew, etc.
  • The day length


  • Last snow or last frost of Spring
  • First snow or first frost of Fall
  • Date a local lake or pond freezes in the Fall or opens in the Spring
  • Date of the first mosquito bite of the season
  • Anything else of interest to you

Collecting Plant Phenology

Plants used for phenological observations are called “indicator plants.” Good indicator plants need to be common to a wide geographical area, hardy, easy to recognize, and easy to grow. They should have short, well-defined bloom periods, with blooms and fruits recognizable from a distance.

  • Bud opening
  • First leaf
  • First flower
  • 50% bloom
  • 90% bloom – full bloom
  • Petal fall
  • Leaf drop
  • Seeding
  • Color changes
  • Animals

Track first appearance

  • migration
  • courtship
  • breeding
  • flocking
  • hibernation, if the animal hibernates

For specific animals:

  • Amphibians (frogs & toads) – first singing, egg laying, life stages
  • Birds – migration, courting rituals or nesting dates
  • Insects – dates of appearance/emergence or life stage cycles
  • Mammals – dates of hibernation, courting rituals, birth of young

After a year of two of tracking such changes, you should have some very useful information. This data can be used for vegetable and flower gardening planting, harvesting and pest management. This is great information to put in a nature journal or to scribble on a calendar.

Or join a citizen science project and hone your data collecting skills.

Citizen Science



More Related Posts

Phenology is Deep Ecology

Using the Pleiades as a Natural Calendar (with video)

The Grinnell System: An Overview 

Catalog for the Ginnell System

Basic Information Keeping a Nature Journal

Citizen Science and Nature Journal Keeping

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