May 11 - 20

 

Racine has 14 hours and 48 minutes of daylight and Superior has 15 hours and 14 minutes of daylight at the end of the period. Southern Wisconsin gains 21 minutes of daylight and northern Wisconsin has 24 minutes more than the previous period.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Bird migration: Mid-May is the peak of warbler migration. In addition, peak numbers of flycatchers, thrushes, and vireos are moving through the state or setting up territories. The main event is upon us – so much to see and so little time. Millions of warblers, flycatchers, vireos, and sparrows are on their way to the Northwoods and Canada. Hosts of favorite nesting birds such as orioles, tanagers, and grosbeaks are arriving on their breeding territories from farther south. The following article was written to enlighten birders in the Passenger Pigeon.

 

In recent spring migrations, flurries of posts on social media outlets for birders revolved around potential sightings of species not normally associated with early arrival in Wisconsin. Many birders entered into the exchanges regarding the identification marks. This article does not delve into the intricacies of the correct identification that is the job of the Bird Records Committees, but does take a closer look at the intricacies of migration.

 

The predominant factor determining when a neotropical migrant decides to move is day length. The farther south they spend the winter, the more they are tied into daylight as the primary migration cue. A Blackpoll Warbler munching on bugs in Trinidad or an American Golden Plover resting on the paramo of Peru will not react in the slightest to a warm weather front entering Wisconsin on April 4. These migratory cues are hard-wired and long-lasting, but things can change. A small proportion of the sedentary house finches released in New York from California have now developed migratory habits. Other species are tempted to linger on the Gulf Coast due to a warming climate or a dramatic increase in feeders. These individuals have the capacity of change their wiring and adapt to the new conditions. Even with these changes, early movements of neotropical migrants is very rare and needs to be put into context.  

 

Below is a table of selected species indicating average first arrival dates in southern Wisconsin, and the next column is when the bulk of the migrants are expected to arrive in southern Wisconsin.  Most birders will see their first bird during the times of heavy movement. A final caveat – southern Wisconsin is not a straight line across the state. The cooling effects of Lake Michigan, oft times delays movement in spring, whereas, warming along the Mississippi River permits a bulge of movement north.

 

Table1: Phenological Average First Arrival Dates and Peak Migration Dates for Selected Species

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Mid-May wildflowers: Mid-May is the peak time to visit rich woodlands, but also visits to wet-mesic prairies, northern pine forests. The spring floral display reaches its peak intensity with most of the spring ephemerals visible on the forest floor. 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 11 – 20

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Lepidopteran activity increases: Plants in the woods and fields grow rapidly during May, thus providing food for many moth and butterfly. 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 dusted skipper, is considered rather rare in the state. The GNW ecologist with permission of the landowners found dozens of these skippers in flight and nectaring near the Lower Chippewa River. The prairies are part of a large complex of prairies almost all on private land, but comprising more that 25% of the known prairie acreage in the state.

 

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

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Lapland Longspur: Why is this winter bunting still hanging around? The answer is quite simple – early spring has barely started on its breeding territory in the arctic tundra. In most years, the spring thaw occurs in June. Surprising to many birders and most naturalists, Lapland Longspurs are regular migrants through the state from mid-April through much of May. They can be found in traditional prairie pothole locations of northern Dane, southern Columbia and western Fond du lac Counties. They can be found near flooded field in these locals, but they are quite skittish. On very rare occasions a Smith’s Longspur will join them. Only on rare occasions will birders look into freshly plowed field for birds, and by doing so, they are sometimes rewarded with brilliantly plumaged longspurs. 

 

Six-spotted tiger beetle: One of the most identifiable tiger beetles is the Six Spotted Green Tiger Beetle. They are iridescent, bright green colored insects, which lives along the paths of forested regions, instead of the open sandy areas where most tiger beetles are found.

This species has a two-year life cycle. During this time it goes through a complete metamorphosis. This means they have four separate stages during their lifetime. The first is the egg stage. The female lays eggs in individual holes in the ground during June or early July. After hatching, the larval stage begins. The larva resembles a caterpillar, but it lives underground and catches prey with powerful jaws. It then pupates near the surface and emerges as an adult in spring. The beetles are sexually mature in the spring, mates, and dies during the summer months. This tiger beetle, no more than a half an inch long, is a ferocious predator in the insect world.

 

Kirtland's Warbler: Kirtland's warblers build their nests on the ground in stands of young jack pine. The jack pines must be just the right height (about 5 to 16 feet tall) and the trees must be spaced to let sunlight through to the ground. Sunlight helps keep lower tree branches alive and bushy, hiding the nest beneath them. When the trees grow larger their upper branches block the sun, causing the lower branches to die. Grasses and other plants also become less dense. The warblers then must find other nesting areas. After nesting and raising their young, Kirtland's warblers migrate to the Bahamas where they winter in scrub thickets. Since the mid2000s, they have nested in Wisconsin.

 

Tidbits:

• Several bird species that had peak arrival numbers for southern Wisconsin are now either moving through the Northwoods or are on breeding territory. These species include: Ruby-throated Hummingbird, Warbling Vireo, Chestnut-sided Warbler, Black & White Warbler, American Redstart, Ovenbird and White-throated Sparrow.

• Prothonotary and Kentucky Warblers should be on territories in southwest Wisconsin.

• Common Tern numbers can reach into the tens of thousands along the Lake Michigan shore.

• Though difficult to observe, the Arctic shrew molts at this time of year.

• Peak migration for the red bat occurs but it is seldom observed in the state.

• Mid-May is peak litter time for the raccoon.

• To the bane of many lakeshore residents, lake fly numbers explode along Lake Winnebago.

• Nature enthusiasts in the Northwoods should start looking for morels, if a warm spring rain has occurred within the past 5 to 7 days.

• For those paddling on the larger rivers, look on the shore for the first basking soft-shelled turtles of the season.

• Sand terraces along the lower Wisconsin, lower Black, lower Chippewa, and Mississippi rivers should be investigated for the first of the season six-lined racerunners.

• Both Cope’s and eastern gray tree frogs call in earnest starting in mid-May.

• Prairie skinks can be seen basking in open sand areas of the northwest barrens. Look for both prairie and five-lined skinks amongst the rocks at Interstate Park.

• Bracken fern fiddle heads pop-up all over the dry sandy barrens and pine forest of the Northwoods.

• Naturalists plying the central sand barrens should keep an eye out for the Haldeman’s grasshopper. This species is found sparingly in areas of sparse vegetation on sandy soils.

• Eyed click beetles are easily identified by two large eyes spots on the pronotum. These spots are outlined in white. This species is common in woodlands and is attracted to pruned branches. If you find one – capture the beetle and place it on its back. They make a clicking sound to flip and turn upright. This natural mechanism can be great entertainment for children.

• Silver maple seeds disperse, helicoptering to the ground.

• Aspen cotton can fill the sky under light winds.

• Maidenhair ferns unfurl showing their beautiful symmetry.

• Visit gravel riffles in clear water rivers to observe the colorful rainbow dater guarding its territory.

• Spawning for largemouth bass commences in shallow vegetated areas over sand and gravel.

• Mid-May is the average time naturalist and gardeners start seeing spittlebugs. About 20 species occur in the state and they can be found on many types of plants from grass to giant pine trees. The spittle is actually plant juices mixed with air and excreted from the rump of the larvae for protection. Adults are known as frog hoppers.

• Fertile spikes of the sensitive fern develop in mid-May and persist throughout the following winter.

• May (or June) beetles of the genus Phyllophaga are some of the most recognizable in the state. There are 18 species found in Wisconsin and from mid-may well into June they can be seen around lights at nights. They are familiar, because an incoming beetle has an obviously buzzing sound, which is followed by a thud when it hits a screen or wall. They are obvious and well liked enough that Baldwin has annual “June Bug Days”.