May 21 - 31

 

Racine has 15 hours and 6 minutes of daylight and Superior has 15 hours and 35 minutes of daylight at the end of the period. Southern Wisconsin gains 18 minutes of daylight and northern Wisconsin has 21 minutes more than the previous period.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Bird migration: Late-May has bird migration mostly winding down. Almost all of the land birds are on territory. The peak of warbler migration has passed for most species, but a few species peak during this time frame and others are still lingering in the woods. In addition, cuckoos, which feed mainly on caterpillars, arrive to start the feasting on new emerged fuzzy caterpillars. Most of the peak migrants are tundra nesting shorebirds, which makes sense, because their summer habitat is still frozen solid until June. The following table highlights those species, whose peak migration numbers occur during late May.

 

Table 1. Bird Species with Peak Migration Numbers, May 21 – 31.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Late-May wildflowers: Late-May is a great time to visit rich woodlands, but also visits to prairies, and northern barrens can be rewarding. The spring floral display is still going strong with many species reaching their peak intensity. Some of the early species such as spring beauties may be setting seed and withering. Whereas, other habitats, like open bogs are just starting to display colorful flowers. The Northwoods, predictably is a little later and many of the mid-May bloomers from the south are now in full bloom in the northern forests and meadows. Sedge Meadow and barrens areas should not be overlooked, as several interest species bloom in May. The following table indicates some of the more common species to be expected on your ventures.

 

Table 2. Native Wildflowers with peak blooming times May 21 – 31

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Lepidopteran activity continues to increase: Plants in the woods and fields grow rapidly during May, thus providing food for many moth and butterfly species. Most of these species do best in summer and early fall. There is, however a contingent that does best earlier in the growing season. The following table lists a few of the more recognizable species, their habitat and larval food plants. One species on the list, the Karner blue butterfly, is a federally-listed species. This species is considered rather rare in the world, but it can be relatively common in “pine barrens” areas of the state from Waupaca to Burnett Counties.  

 

Table 3. Large and more recognizable Lepidopterans whose flight period either starts in late-May or is limited to this time period.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Slender glass lizard: The slender glass lizard is a legless lizard with a long slender body and tail. It can grow to almost 30 inches in length. The tail is nearly 2/3 of the bodies length. The general body is a bronzy -tan with a dark brown band running down the middle of the back. Slender glass lizards are often mistaken for snakes, but can be distinguished ear openings, and moveable eyelids. This is Wisconsin’s only legless lizard.

 

These lizards are threatened in the state due to very restrictive habitat needs and habitat loss. They inhabit savannas, barrens and oak woods, but need to have very sandy soils in which they can burrow. This species can also survive in sandy roadsides if they are not maintained with frequent mowing. Their preferred habitat, sandy oak savanna has been drastically reduced in the State and is now limited to widely scattered location in the central sands. .

 

Slender glass lizards spend most of their time underground. Even during times of peak activity, only a small percentage of the population is on surface. These periods of activity vary by season: aboveground activity spikes in late May and early June and again from late July to early September. A naturalist should consider luck on their side, if they find one. It is best to simply observe, if they are captured, they may lose their tail. This discarded tail will break into many smaller wiggling pieces, thus the name glass lizard.

 

Bullsnake: The bullsnake is our largest snake reaching 6 and 1/2 feet in length. They are large constrictors that feed mostly on rodents with pocket gophers being a favorite prey. They inhabit sandy prairies, oak savanna and barrens, oak woods and pine barrens. They hibernate in rock crevices with blue racers, timber rattlesnakes and gray rat snakes and emerge from hibernation in early May. Naturalists’ best opportunity for observing bullsnakes is in mid- to late-May, when they are mostly on the surface and either looking for mates or fending off competing mates. They preform twisting duels to get the upper hand on rivals. After June, the bullsnake is very difficult to observe, since they are mostly underground in rodent burrows.

 

Tidbits: 

• Green frogs reach their peak vocal intensity in southern Wisconsin. It will be a few more weeks before peak calling occurs in the Northwoods.

• Red-backed Salamanders become active in the forest debris layer. Highest numbers of these salamanders are near ponds in old-growth forests.

• Red cedar cones (also incorrectly called berries) start development.

• Moose calves are usually born during this time period.

• White pine pollen usually reaches its peak during this time frame. The stick yellow stuff can cover cars and roofs, and unfortunately can be allergic to some people causing extensive cough fits.

• As the pollen falls in the north, eastern cottonwood sheds its seeds mixed in with light wispy cotton farther south. These “cotton falls” usually occur on days with lighter winds and can appear like snow on the warm breezes.

• The pine barrens and dry pine forest have bracken fern fiddleheads everywhere.

• Fish species spawning in Wisconsin’s rivers and streams at this time are common carp, bullhead species, white bass. Although, all of these species may spawn earlier or later depending on water temperature in any one given year.  

• Toothed herrings are a family of fish little known in the state. The mooneye and goldeye are big river fishes. They are migratory species that survive the winter in deep pools than migrate to spawning areas in May. These migrating fish can occasionally be seen in larger river especially the lower Wisconsin and lower Chippewa Rivers.

• At the end of the month keep an eye on small clear streams for the first emergence of the ebony and river jewelwing damselflies. These two species are our most endearing damselflies, because they are iridescent black and green coloration. They slowly work along these placid streams making observation easy.