St. Olaf College Phenology

What is Phenology?

Phenology is the branch of science dealing with the relations between climate and periodic biological phenomena (or events). It is the study and recording of cyclic events in nature in response to seasonal and climatic changes in the environment. Events commonly recorded include:

  • bird migration
  • plant budding/flowering
  • falling leaves
  • ponds freezing/thawing
  • emerging hibernating animals
  • appearance of insects

Perhaps the most common events recorded are those of the first birds of each species returning to the N. latitudes in spring. Below is the Spring Phenology list for 2005. You can refer to it to see when various bird species return to this area as well as other events in nature. Seasonal comparisons can also be made of varying temperature, moisture, sunlight, ice-out on lakes, etc., and their effects on plant and animal activities. With increased interest in global warming, scientists can compare past and present phenological records. This can give indications of rapid climatic changes.

In addition to this web site, a large phenology chart is posted on the Student Naturalist bulletin board by the ecology lab in the Science Center (SC 248) every spring semester. If you see a natural event for the first time this spring, please submit the DATE, EVENT, and your NAME to Dr. Gene Bakko ( or add it directly to the chart in the Science Center.


Phenology Chart
St. Olaf College and Rice County
Spring 2005

Date Event
20 Black-Capped Chickadee mating calls
26 N. Cardinal mating calls

13 Striped Skunk roadkill
14 Amer. Robin calling
26 Bald Eagles riding thermals over campus

2 Mourning Doves cooing
6 E. Chipmunk out of hibernation, Great Blue Heron
7 Horned Lark
12 Pileated Woodpecker, Red-Tailed Hawk, Canada Geese pairing up for breeding, 13-Lined Ground Squirrel
13 Wild (tom) Turkeys strutting
18 Turkey Vulture
24 Red-Winged Blackbirds
25 Common Grackles
26 Tundra Swans, Comma Butterflies
27 E. Bluebirds
28 Killdeer
29 Tree Swallows, Wooly Bear Caterpillars, Song Sparrows singing, Northern Shovelers, Lesser Scaup, Ring-Necked Ducks, found shed antlers
30 Mallard pair
31 Golden Crowned Kinglet, E. Phoebe, Red-Breasted Nuthatch, purple violets blooming, Tiger Salamander

1 Hermit Thrush, Gray Fox behind Rand Hall, Yellow Throated Warbler (rare visitor to MN), Rhubarb and Day Lilies emerging
2 Leopard Frogs chorusing
3 Woodcock mating dance N. of hospital, N. Flicker, Fox Sparrow, Pied-Billed Grebe, Buffleheads
5 Red-Bellied Woodpecker, Bloodroot blooming, ice out on large pond, Dragonfly, Hornet, Amer. Coot, Belted Kingfisher
6 Wood Frog and Western Chorus Frogs chorusing
8 Yellow Bellied Sapsucker, Wilson’s Snipe, Blue-Winged Teal, Chipping Sparrow
9 Common Garter Snake
10 Woodchuck, Ruby-Crowned Kinglet, Swamp Sparrow, Yellow-Rumped Warblers, Muskrat
14 Garter Snakes mating, Trout Lily blooming
15 Toads chorusing
16 Ruddy Ducks, N. Rough Winged Swallows, Palm Warbler, Field Sparrow, Savannah Sparrow, Rusty Blackbird, Common Merganser, Am. Goldfinch
17 Brown Thrasher
19 Sora
20 Double-Crested Cormorants
23 House Wrens
24 Yellow-Headed Blackbirds, White-Throated Sparrows
29 Bank Swallows

2 White Pelicans @ Union Lake
3 Peregrine Falcon over large pond, Sandhill Cranes, Osprey, Lesser Yellowlegs, Orange-Crowned Warbler
5 White-Crowned Sparrow
6 Marsh Wren, Warbling Vireo, Yellow Warbler, N. Waterthrush, Louisiana Waterthrush, Rose-Breasted Grosbeak, Clay-Colored Sparrow, Grasshopper Sparrow, Harris Sparrow
8 Great-Crested Flycatcher
9 Chimney Swift, Sedge Wren, Gray Catbird, Tennessee Warbler, Nashville Warbler, Chestnut Sided Warbler, Common Yellowthroat, Wilson’s Warbler, Indigo Bunting, Lincolns Sparrow, Baltimore Oriole
10 N. Pike are post spawn, Solitary Sandpiper, Greater Yellowlegs
11 E. Kingbird, Least Flycatcher
13 Blue-Gray Gnatcatcher, Gray-Cheeked Thrush, Swainsons Thrush
15 Blue-Headed Vireo, Red-Eyed Vireo, Magnolia Warbler, Black-Throated Green Warbler, Blackburnian Warbler, Bay-Breasted Warbler, Blackpoll Warbler, Black-and-White Warbler, Am. Redstart, Scarlet Tanager
16 Common Nighthawks, Ruby-Throated Hummingbird
20 Red Pine pollen storm