March 21 - 31
Racine has 12 hours and 41 minutes of daylight at the end of the period and Superior has 12 hours and 46 minutes of daylight - an increase of 32 minutes in the south and 36 minutes in the north from the previous period.
American Woodcock: The American Woodcock is regarded by many as the quintessential harbinger of spring. They usually arrive in late March and the males establish territories on their singing grounds. These grounds are in open or semi-brushy areas of a few acres or more.
After arriving, the American Woodcock or timberdoodle initiates territorial advertisement. Dawn and dusk displays are most common, but they occur sporadically throughout the night. Ground calls are exemplified by a loud, buzzy - peent. If a naturalist is fortunate enough to be extremely close, tuko sounds precede the loud burst. After many ground calls the timberdoodle takes flight in wide circles, which produce mechanical wing twitter noises. After reaching 300 to 400 feet, he utters loud chirping notes as he zigzags back to the ground. Occasionally these flights can be followed. With clear skies allowing for extended twilight, listen for the twitters and try to locate the ascending bird. By following the male with binoculars and observer is rewarded, garnering an outstanding spectacle.
American Woodcock’s favorite food is earthworms, which comprise approximately 70% of their diet. Earthworms have been part of Wisconsin’s fauna less than 200 years (see next article). This fact leads a natural observer to ask what did they eat before earthworms? The answer is many types of insect larvae, other types of worms, snails and beetles.
Earthworms: Earthworms are aliens. Soils without native earthworm tracked the extent of the last glaciers. Areas covered by glaciers have no native earthworms. The southern US has native earthworms and they are very slow to recolonize northward, moving approximately 5 to 10 meters per year. Alien earthworms, also move slowly. Unless humans move alien worms into local woodlands, it is very difficult for these worms to get there on their own.
These alien earthworms first arrived in plants and soil brought to the Midwest from Europe on ships during the late 1800s and early 1900s after the Welland Canal was opened. Soil and rocks were often used as ballast in the ships and then dumped here. European settlers, also wanted familiar plants and imported many types bringing the attendant earthworms along. Further spread has occurred by discarding fishing bait, because all common fishing bait worms are non-native species.
Leaf litter is home to an exceptionally rich community of small creatures including soil organisms, insects, spiders, small mammals, salamanders and toads. The forest relies on natural organic compost that occurs when leaf litter is processed by critters and decays slowly. However, non-native earthworms eat the leaves in this litter and cause it to disappear quickly and completely. This results in a loss of the natural fertilizer produced by leaf decay with fewer plants and flowers growing on the forest floor. As a result, there may be a catastrophic loss of leaf litter critters. In addition, we now know that the greatest abundance of worms is found where invasive shrubby European buckthorn is at its peak density.
Currently, researchers are investigating the idea that ecological restoration, which improves degraded habitat, also reduces earthworm populations. Preliminary results of this work suggest that areas with higher plant diversity that have been under restoration or management for long periods of times have lower earthworm populations. However, earthworm invaded areas may stay invaded for several years after the restoration has begun. This conclusion supports ecological management of our natural areas to reduce problems associated with alien earthworms as one of numerous benefits.
What can you do:
Support and/or participate in ecological restoration of our natural areas.
Keep non-native compost and worms out of the wood lands. Freeze the compost for at least a week to kill the worms in the live compost, before you use on compost near a wooded area.
Do not dump fish bait or other worms in the woods or water; toss any unused bait in the garbage.
Growing degree days: Growing degree days have been used widely by botanists and entomologists to determine flowering times and insect emergence. The most active use of degree days has been for agriculture and horticulture purposes. Without drought or other unusual weather phenomenon, plants typically grow in a stepwise fashion that is influenced strongly by air temperature. Growing degree days measure the daily accumulation of temperature. Likewise, insects need to have their emergence coincided with plant development.
Growing degree days are defined as the difference between the average daily temperature and a base temperature, which is 50°F in most cases. The average daily temperature is calculated by adding the minimum observed temperature to the maximum observed temperature for the day and dividing that value by two, then subtract by 50.
For those who prefer formulas, it looks like this: (Max temp observed + Min temp observed)/2-50° F=Growing degree day value).
Growing degree days for specific dates can then be added together to determine the cumulative growing degree day value for a certain period.
This web document provides average dates for when things happen. However, especially in early spring, these averages can fluctuate greatly.
More precise knowledge of when to expect the first blooming hepatica or spring peeper call is better determined by degree days rather than calendar date. Degree days in your area can be found on the National Oceanographic and Atmospheric Administration’s (NOAA) website.
Tiger salamanders: Eastern tiger salamander is one of our largest terrestrial salamanders. They typically grow to 6 to 8 inches. Adults are usually dark brown or black, marked with yellow, gold or olive blotches. Tiger salamanders belong to a group of burrowing amphibians known as mole salamanders. They live in tunnels or beneath debris and stay underground for much of the year. They need both aquatic and terrestrial habitats to complete their lifecycle.
In late March (most years) after the ground thaws and the weather warms, tiger salamanders emerge. When overnight temperatures are in the mid 40s and a warm hard nighttime rain occurs, these salamanders can be found in large numbers moving to nearby ponds to breed. Once at their breeding grounds, the salamanders engage in an elaborate courtship display. The naturalist should look for these salamanders moving to their breeding ponds in late March.
Devils Urn: Many naturalists consider their favorite bird’s arrival, woodland frog choruses, or blooming plants as harbingers of spring. However to mycologists, the Devil’s urn fungi are considered the trumpeter announcing spring’s entrance. The scientific name of this fungus is Urnula crarterium. In early spring, these black caps emerge through fallen leaves. They emerge as finger-like projections that soon develop small blackened craters at their tips. They look like little fingers pushing up from the soil, but in a span of a few days these little fingers widen at the top and split all open to form a crater.
This timeframe usually produces the first eastern chipmunks stirring around the woods.
Woodchucks (groundhogs) usually emerge from their burrows in late March.
During this time period, a visit to known herp hibernacula is in order. South-facing rubble areas on warm sunny days can produce the massive balls of Eastern garter snake emerging from their winter hibernation locations. A few weeks later in the season these snakes disperse into their summer range.
On average these bird species will reach peak density is during this time: Common Loon, American Widgeon, Gadwall, Northern Shoveler, Green-winged Teal, Northern Pintail, Wood Duck, Turkey Vulture, Eastern Meadowlark, Eastern Bluebird, Eastern Phoebe, Yellow-bellied Sapsucker.
Late March is courtship and nest initiation for the Barred Owl. During this time frame their call repertoire is much larger than the “who cooks for you” calls heard throughout most of the year.
With water temperatures into the 40s, listen for spring peepers followed closely within two days by the first chorus frog calls.
Listen for wood frogs in the north woods.
Normal emergence for comma, gray comma, Compton’s tortoiseshell, and Milbert’s tortoiseshell butterflies occurs during late March.