Protect, restore, and improve the highest quality natural communities in Wisconsin.
September 21 - 30
Racine has 11 hours and 47 minutes of daylight and Superior has 11 hours and 44 minutes of daylight at the end of the period. Southern Wisconsin loses 32 minutes of daylight and northern Wisconsin has 33 minutes less than the previous period. The autumnal equinox occurs on the 23rd. September 28 is the full moon. Names for this full moon (Barley, Rice, Changing Color, and Harvest) depend upon cultural tradition.
Rare birds and numbers of birds migrating: A bird alert subject line read: MANGO! My first impression was a fruit-based joke. No! Green-breasted Mango! The first record north of Texas and North Carolina had the Midwest birding world chatting for over a month. Birders plans were changed and schedules altered in order to make an attempt a seeing this bird. Most birders did succeed. A few years ago an immature Green-breasted Mango visited a Beloit hummingbird feeder. The owner of the feeder graciously hosted nearly 900 birders. The visiting birders got to place a check mark on their life list for this once in a lifetime bird.
I was not one of the 900. I had seen the species in its natural habitat numerous times on trips to Costa Rica and the Yucatan. A wayward bird coming to a feeder did not generate an urge to make a trip to add the species on a list. I do not tally lists as an exercise, but there’s no question in my mind, if I had never seen a Green-breasted Mango before, I would have been there in a flash. My rationale would have been, it’s expensive to travel to the tropics and this may be the only chance I have of seeing this species.
Simply adding a checkmark to a list had little appeal. To me, big lists are the result of a simple equation - the ability of a birder to identify species multiplied by time available and means. The least important factor is the skill of the birder, as exemplified by James Vardimann. He was first person to make a serious assault at cracking 700 species seen in North America in one calendar year. He was only a moderately skilled birder and extensively used expert birders to find, identify and corroborate his sightings. However, he did have the time and the financial means to make it happen.
While the listing was very low on my personal radar screen, the mode of its movement and magnitude of dispersal were extremely intriguing. How did this bird get here? Was there some event that caused it to be lost in the Midwest? Even more intriguing to me is this question – Was this the only wayward mango? Let’s take a closer look at these questions.
The obvious answer to the first question is it flew here. More deeply though was the route direct or something different. We cannot answer this hyperbole, because the bird did not have a transmitter. The second question, however, is open to speculation.
Mango records have been previously limited to Texas and North Carolina. The Wisconsin bird, however, was not a unique vagrant. Another bird appeared in Georgia. Again, we have no way of knowing what causal factors were involved to make this bird fly to Beloit. The intriguing lesson is the way birders answer these speculative inquiries. Some suggested one the two category 5 hurricanes that hit the Yucatan and Nicaragua in late August and early September was the catalyst for vagrancy. Other birders were adamant expounding a simple answer - the bird was lost.
Several years ago, a specimen of a Sooty Tern was found on a road in Columbia County. At the time, nearly everyone writing or speaking about this bird was positive a hurricane pushed the bird into the state. Over the decades sightings by citizen-based scientists have aided in understanding of hurricane-induced movements by seabirds, Category 1 hurricanes are fully capable of being a catalyst for seabird outfalls. Less clear are the impacts on land birds. Continued documentation of wayward birds in the fall will continue to add to analytical evaluation of hurricane effects.
Was this the only wayward mango? From the previous revelation another bird was seen in Georgia, the answer is obviously, no. In a broader context, how many “rare” birds do birders actually record? Or in other words, how many do we miss?
A standard opinion has developed over the past ten or so years - finding of rarities, while certainly a function of birding intensity and skill, is also a product of simple serendipity. The tools available for prepared mind of today’s birder makes identification of rarities more likely and correct, but identification skills are less important than being in the right place at the right time.
Is this proposition true? Let’s look at records for a species not consider a rare bird in Wisconsin. The Gray-cheeked Thrush moves through the state in spring and fall. Migration paths in our state are widely dispersed with no apparent super concentrations in any one locale. Partners-in-Flight estimates the world population at 12,000,000 birds with a moderate degree of confidence. The broad-spectrum migration movement patterns indicates approximately 1/6th of the migration front occurs in Wisconsin. Assuming somewhat even distribution across the front, approximately 2,000,000 or more Gray-cheeked Thrushes most likely pass through the state each fall.
In the fall of 2007, the combined number of Gray-cheeked Thrush observation reported by all ebird and Wisconsin Society for Ornithology forms was 25 birds. Of that 2 million-bird movement, the best birders in the state observed 1/100th of one percent of the birds. Yes, one land bird in 10,000 is seen. This data compares precisely what other birders found in Colorado. Of course, Gray-cheeked Thrushes are secretive and other species are much easier to see. Open water species, large distinctive species, and feeder birds are most assuredly seen in a much higher percentage. We miss many more than we see.
Migrating pelagic birds: A few decades ago, birders were in much lower numbers than they are today. Birders in the far north were virtually unheard of until the 1970s. Today a vibrant birding community resides in the Duluth-Superior area. Better infrastructure for transportation and especially the boon in communication networks permits almost instantaneous information flow and rapid access. All of these factors have led to “jaegerfest”.
Each fall on the weekend closest to the autumnal equinox, hundreds of birders gather in Superior for the annual Jaegerfest. They gather on the beaches in numbers, scanning the waters with high powered telescopes in hopes of finding jaegers, terns, or gulls that normally migrate well out at sea. In most years, they are successful.
In the 1970s, a few intrepid Wisconsin birders, GNW ecologist included, began birding the Superior area in fall. These long trips occasionally produce tantalizing records of these pelagic species. The developing core of Minnesota birders with the opportunities in their backyard found these pelagic species to be rare, but regular visitors each fall. Through the 1980s and 1990s, the road systems allowed much more rapid access to the birding sites.
Jaegerfest thus came into being. The event is promoted by local tourism bureaus and is well attend. Participants have a better than average chance of viewing one or perhaps all three species of jaeger. Occasional glimpses of the rarely seen Sabine’s gull are had and there is a remote chance of finding an Arctic Tern. Why all the excitement among the birders?
The jaeger species (Pomarine, Parastitic and Long-tailed) all have extended central tail feathers as adults. They also have varying sizes of white patches in their wings both as adults and immature individuals. Their diets are varied and similar to gulls. They will eat fish, squid and other sea creatures, but also will consume berries, insects, rodents, birds, eggs, carrion and offal. They are especially adept at catching lemmings.
The primary behavior, so enthralling for birders, is kleptoparasitism. This long term means stealing of food from other seabirds by aerial pursuit. Jaeger species harass other birds by flying at or alongside, matching avoidance movements until the bird being harassed drops its catch. Then the jaeger snatches the prey item as it falls towards the water.
Another draw card is the flight pattern and shape of jaegers. The Parasitic Jaeger is the mid-sized version and is quite like a falcon in shape and flight agility. The Pomarine Jaeger is larger and bulkier and seems to bully the other birds. The Long-tailed Jaeger is lighter and much more maneuverable with an unmatched adult plumage.
The pelagic gull is the Sabine’s Gull. This species does not use parasitism tactics of jaegers, but is most admired for its plumage. As far as gulls go, the species is very showy. It has a striking wing pattern of black and white, which combined with a graceful flight pattern reminiscent of tern makes this species a favorite.
Late September floral and fruiting peaks: Peak blooming is mostly done for the season with good numbers of asters, goldenrods and gentians still in bloom, although their peak has past. Some fruit and nut producers are reaching their peak as well as several species are attaining peak fall colors.
Table 1. Native Wildflowers with peak blooming, fruiting or color times September 21 – 30.
Red-bellied and brown snake migration: These small snakes migrate to overwintering hibernacula. They are most often seen on roads and trails from now through mid-October. Both species hibernate with other snakes such as smooth green snake and garter snakes species. Hibernation locations are in ant mounds, rock crevices, and building foundations. They can be easily missed in these movements. The young snakes are quite small and may appear as earthworms on the road. Several years ago in late September, Is counted 23 dead brown snakes on a very rural road with little traffic. The largest specimen was six inches long. Naturalist should watch for these diminutive snakes in their fall migration.
Papaipema and buck moths: Two groups of late September moths are interesting for different reasons. The buck moth is colorful day flying moth. The Papaipemas are difficult to distinguish borer moths that are intimately tied to host plants. If the host plants are limited in distribution, then the borer moths are likewise limited and can be quite rare depending upon how much habitat remains.
The buck moth is a resident of moist meadows and does best in higher quality wet prairies. It is distinguished by its black wings with yellow tinged white median bands. They are raping fliers and are best sought between noon and 2pm on sunny days.
Borer moths are more subtly marked. The eggs are laid in fall on or very near the host plant, and hatch in spring. The young larva then burrow into the host plants stalk and many times the roots system where they feed until fall, when the adults mate and lay eggs repeating the cycle. Some of the interesting species found in the state are:
Lily borer moth feeds on lily species in wet meadows.
Aster borer moth feeds on many species of aster is quite common.
Lysymachia borer moth feeds on loosestrife species.
Senstitive fern borer moth feeds exclusively on sensitive fern and is found wherever that fern is found.
Wild indigo borer moth feeds on baptisia species and is limited to native and restored prairies.
Turtlehead borer moth feeds on turtlehead in wet meadows.
Silphium borer moth feeds on prairie dock and limited to native prairie and reconstructed prairies where the host plant is found.
Sunflower borer moth feeds on various sunflower species and can be found where sunflowers are found.
Rigid sunflower borer moth feeds solely on Solidago rigida. The species can be found on native and reconstructed prairies.
Joe-Pye weed borer moth is found wherever joe-pye weed is found, especially sedge meadows.
Culver’s root borer moth feeds on Culver’s root.
Liatris borer moth feeds on sessile blazingstar. This species is rare and found only on a few native prairies in far southeastern Wisconsin.
Meadow-rue borer moth feed on meadow-rues.
Ironweed borer moth feeds on New York ironweed.
Bracken fern borer moth feeds on bracken fern and is found wherever bracken fern is found.
Pitcher plant borer moth feeds on pitcher plant and is limited to bogs were pitcher plant grows.
Bald-faced hornets and German yellow jackets reach their peak numbers and unfortunately, their peak aggressiveness.
Muskrat lodges dot the shallow marshes of the state.
Along the shores of Lake Michigan and wherever mudflats hold shorebirds watch for tundra Peregrine Falcons. They reach their peak migration now and can stick around until freeze-up on favored mudflats and marshes that hold shorebirds and ducks.
Late September usually sees the first migrant Lapland Longspur. Look for them in fields and on muddy shores
Far northern Wisconsin usually sees peak Orange-crowned Warbler numbers in low wetlands shrubs.
Three species of leaf-footed bugs occur in Wisconsin. They can be seen in late September crawling on buildings. Two species feed mostly on conifer seeds and are much more common in the Northwoods.
Box-elder bugs start their annual migration to overwintering locations causing consternation among thousands of homeowners.
Butternut (now very rare)
Wild cranberries (fruit)
Ostrich fern (color)
Bracken fern (color)
New England Aster
Eastern lined aster
Highbush cranberry (fruit)
Streambanks and edges
Dry woods and savannas
Dry-mesic forest and old fields
Bogs and conifer swamps
Dry conifer forest & barrens
Wet meadows & prairies
Wet meadows, swamps
Wet shrubby areas