Phenology

The American Heritage Dictionary defines phenology as “the study of periodic biological phenomena, such as flowering, breeding and migration, especially as related to climate.”

As winter bids adieu and spring weather tiptoes toward us, we are highlighting phenological occurrences that many of us might easily miss or take for granted as we go about our busy lives.

March 26 to April 8
The next several weeks will be prime time for observing migratory birds. Consider buying a good field guide to help you identify them and learn to recognize their songs.

Bluebirds are starting to show up in the Madison area. One place to look for them is the Arboretum’s Longenecker Gardens, where there is a trail of bluebird houses. Eastern phoebes and song sparrows are also arriving.

When you see what you think are Canada geese flying over, look more closely. They could be sandhill cranes. In flight, the cranes’ long necks and legs are extended. Their habitat includes prairies, farm fields and marshes. The late naturalist Roger Tory Peterson described their vocalization as “a shrill rolling garooo-a-a-a, repeated.” Whooping cranes, which are white in color, have been observed traveling with the gray sandhills.

Now that the ice is going out on Lake Mendota, watch for common loons cruising along the shore, biding their time until the northern waters where they nest open up. You will also see tundra swans and early migrating ducks, such as common and hooded mergansers, lesser scaup, canvasbacks and buffleheads. Notice the colorful spring plumage of the males.

According to state climatologist Lyall Anderson, the average date on which Mendota opens up is April 5. The earliest recorded date was Feb. 27, 1998, and the latest was May 6, 1857. Anderson says UW limnology pioneers Edward Birge and Chancey Juday long ago defined ice-out on Mendota as the day you could row a boat in a straight line from Picnic Point to Maple Bluff (or more than 50 percent open).

American woodcocks will soon be performing their mating rituals, described as “sky dances.” The males fly rapidly up in the air in a spiral motion — as high as 200 feet or more — and then back to the ground, making one distinctive sound as they ascend and another as they descend. You may be lucky enough to observe this fascinating activity at twilight near the parking lot at the Arboretum’s McKay Center or in other semi-open fields or pastures.

These unusual birds, nicknamed “timberdoodles,” weigh 6 to 7 ounces. They have long bills that allow them to easily find earthworms, their primary food source. They can consume up to their weight or more in worms each day.

Warm days will bring out garter snakes and ice-out will produce some painted turtle sightings, says wildlife ecology professor Scott Craven. Although a few red bats have been observed recently, Craven says most bats will not be out and about until they have flying insects to dine on.

Mourning cloak butterflies are emerging from hibernation. They are the earliest butterflies to appear. They overwinter as adults in tree cavities, under loose bark or wherever cold winds and predators can’t find them. You might wonder what they eat at this time of year. The answer is sap, especially that of oak trees. They also feed on decomposing fruit. Maybe you will spot them at the compost pile.