Burlington Seasons Clock 2020

How do you know when winter has begun? You could look at a calendar, but everyone seems to have their own definition of when the seasons change: the first flurries flutter out of the sky, you have a tire change appointment, or the ski hill advertises opening day. Nature has its own markers of the seasons, and we want your help tracking them!

Henry David Thoreau marked the dates of blooming wildflowers, the arrivals of migratory birds, and the occurrence of other animals in his time at Walden Pond and Concord, MA. Researchers today are recording some of the same phenophases and using them to track climate change. A warmer climate has changed average animal and plant behavior by days or even months. You can help Wildways document the seasons by adding to our 2020 Burlington Seasons Clock project which is found in iNaturalist.

What is a phenophase?  The scientific term for nature’s calendar is Phenology. A subset of ecology, phenology is defined as the study of the timing of recurring biological events and how these events are influenced by seasonal variations in climate and other ecological factors. A phenophase is an observable stage in the annual life cycle of a plant or animal that has starting and end points. Plants are the most common focus of phenological studies because of their fixed location and suitability for repeated seasonal observation. Timing of budbreak, leafing, flowering, fruiting, and leaf coloring are the commonly observed phenophases. The timing of bird migration, the dates of salamander courtship, and mammalian hibernation cycles are examples from the animal world.

From the first day of Spring 2020 to the last day of Winter in 2021, we will continually update our phenology clock as observations of species in our list (further below) are submitted to iNaturalist. The clock shows when species are in Burlington, or exhibiting certain behavior here, like flowering or collecting in groups. We will also be able to see when species overlap to create a food chain, like monarch butterflies and milkweed. Find below the 2020 clock in progress, our species list, and a finished clock based on observations from the iNaturalist database in Burlington in past years.

Click here to play Wildways Bingo and help with the clock!

Burlington Seasons Clock 2020: Updated monthly

Burlington Seasons Clock 2020 Species List

We encourage you to submit any photos or soundbites of wildlife you find to iNaturalist, but our project will only include these species:


  • American Crow (murders only - that's groups of three or more) 
  • American Robin 
  • Blackpoll Warbler 
  • Black-capped Chickadee (“fee bee” song soundbites only) 
  • Canada Goose
  • Eastern Phoebe
  • Osprey
  • Red-winged Blackbird
  • Ruby-crowed Kinglets
  • Tufted Titmouse (soundbites only)
  • Turkey Vulture


  • Basswood (with flowers only)
  • Eastern Cottonwood (with fluff only)
  • Eastern White Pine (with green pollen only)
  • Pussy Willow (with fuzzy buds only)
  • Red Maple (with flowers only)
  • Silver Maple (with flowers only)


  • American Beaver
  • Eastern Chipmunk
  • Muskrat
  • Red Fox
  • Striped Skunk

Amphibians and Reptiles 

  • Common Garter Snake
  • Northern Leopard Frog
  • Painted Turtle
  • Spring Peeper
  • Wood Frog


  • Bicolored Striped Sweat Bee
  • Black Swallowtail (caterpillar or butterfly)
  • Eastern Box Elder Bug
  • Isabella Tiger Moth (caterpillar or moth)
  • Mourning Cloak (caterpillar or butterfly)

Herbaceous Plants 

  • Common Milkweed
  • Eastern Skunk Cabbage (with red-brown hoods only)
  • Large White Trillium (with flowers only)
  • Ostrich Fern (with fiddleheads only) **please do not pick** 
  • Red Trillium (with flowers only)
  • Round-lobed Hepatica (with flowers only)
  • Purple-flowered Raspberry (with flowers only)

Burlington Seasons Clock Data from Prior Years

Burlington Seasons Clock 2006-2019