Participate in Citizen Science and explore the natural world through PHENOLOGY: The study of cyclic and seasonal natural phenomena, especially in relation to climate, and plant and animal life. To get started, go to Nature's Notebook.

Phenology is nature’s calendar—when cherry trees bloom, when a Vireo builds its nest, When Monarchs migrate, and when leaves turn color in the fall. 

Phenology is a key component of life on earth. Many birds time their nesting so that eggs hatch when insects are available to feed nestlings. For people, earlier flowering of some plants means earlier allergies. Farmers and gardeners need to know the schedule of plant and insect development, and when to plant to avoid frosts. Phenology influences the abundance and distribution of organisms, ecosystem services, food webs, and global cycles of water and carbon. In turn, phenology may be altered by changes in temperature and precipitation.  

Changes in phenological events like flowering and animal migration are among the most sensitive biological responses to climate change. Across the world, many spring events are occurring earlier—and fall events are happening later—than they did in the past. However, not all species are changing at the same rate or direction, leading to mismatches. How plants and animals respond can help us predict whether their populations will grow or shrink – making phenology a “leading indicator” of climate change impacts.

Why Observe?

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Going outside to look at plants or animals up-close will expand your knowledge of nature and open up new ways you experience the great outdoors.



Where you observe is up to you. Participating is an exciting way to experience your favorite trail, neighborhood park, or even your own backyard. Explore EDI's Phenology Walks at Crestridge Ecological Reserve or San Diego National Wildlife Refuge's Interpretive Loop along the Sweetwater River.


You can intimately connect with plants or animals that you see all the time in a brand new way. As an observer, you’ll notice things you never saw before. The slightest blush on a sycamore leaf that foreshadows the coming fall. The new, more vibrant feathers some birds put on before mating. The swelling of a palo verde bean pod as it grows. You can develop a more nuanced appreciation of our natural world when you participate in Nature’s Notebook.


Researchers, resource managers, educators and others use your data for scientific discovery and decision-making. Your data are a big deal!

Phenology data help us predict threats to people and the environment such as wildfires, drought or flooding. They help us decide the timing of events, from when to harvest or irrigate land to when to conduct controlled burns in forests. You can look at national climate trends at USA National Phenology Network.

For assistance with getting started visit our Learn How to Observe page where you will find step-by-step instructions and video tutorials to help you through the process. 


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