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Cofrin Center for Biodiversity

Archive for the ‘Biodiversity’ Category

Snapshots that help conserve shorebirds in decline

Scientists collect a snapshot of a bird’s life when they capture, band, and release it. Each coded band and any data collected at the same time like date, location, sex, age etc. are recorded in a database that can be shared by scientists around the world. When the same bird is seen somewhere else, that observation location provides another snapshot that is added to the database, helping scientists to reconstruct the movements of individual birds. This continuously growing database makes it possible to study dispersal and migration, behavior and social structure, life-span and survival rate, reproductive success and population growth.

Environmental Science & Policy Master’s candidate Tom Prestby is observing shorebirds migrating along the lower Bay of Green Bay (Brown County, Wisconsin, USA) in order to provide much needed information about the importance of near shore habitat for numerous species of conservation concern including three species in high peril and 12 in high continental concern.

Semipamated Sandpiper photo by Tom Prestby

Semipalmated Sandpipers on the shore of the Bay of Green Bay.

He photographed the Semipalmated Sandpiper shown here in late May 2015 at his research site in Green Bay. The code on the blue band on the bird’s leg allowed him to discover that it was banded on January 14, 2014 in Maranhao, Brazil, and so had traveled nearly 2000 miles to get to Green Bay. Semipalmated Sandpipers, so-named because their toes are webbed for only part of their length, breed on open tundra, so it’s journey is only a little more than half finished. It still must travel another 1200 miles or more to northern Canada and Alaska to breed this summer, resting at along mudflats, sandy beaches, shores of lakes and ponds, and wet meadows. These birds make that incredible 3000 mile journey in only about two months time and rely mostly on stored fat reserves to power them through migration.  Summer is short in the arctic, so after they breed they begin their fall passage in July at a more leisurely pace and typically arrive back in their South American wintering grounds by mid-October.[1]

Unfortunately, this species is on the 2014 State of the Birds Watch List, which lists species most in danger of extinction without significant conservation action. Even though populations appear to be stable at some arctic breeding grounds in Alaska, surveys by researchers in Canada and the United States indicate that the numbers of birds reaching South America wintering grounds have declined by 80% over the last 20 years. Canadian scientist Stephen Brown who has been tracking the birds as they arrive on Coats Island in the far north of Hudson’s Bay explains, “We need to understand the migratory pathways of the species in order to know where the decline is occurring, and what can be done to reverse it.”[2]

Prestby’s observation is helping other scientists to do just that. He is continuing to monitor shorebirds at his research sites including the recently restored Cat Island Chain in person and through the use of remote cameras. He is enthusiastic about his graduate experience. “It is fascinating to be able to look into the life of one of these birds and very satisfying to contribute to a great database!” His master’s research will provide important information about shorebird migration and use of wetlands encircling the bay of Green Bay that will help scientists to better understand and conserve these trans-American travelers.


1. All About Birds:

2. Manumet Center for Conservation Studies:


Considering a career in Environmental Science? Learn more educational opportunities for undergraduate and graduate students at the University of Wisconsin–Green Bay, the Original #EcoU!




Mussel Man!

Earth Day is April 22nd and is celebrating its 45th anniversary this year. This year we want to celebrate the month of April by showcasing our commitment to protecting the environmental health of our local communities, Wisconsin and the planet through environmentally based education, research and outreach at UW—Green Bay, the Original EcoU!


Freshwater Mussels from the Oconto River.

Freshwater Mussels from the Oconto River

North America has the highest mussel biodiversity in the world, with over 300 species, but more than 40% of those species are imperiled, especially in the Midwestern states. According to the US Fish and Wildlife Service, no other group of animals in North America is in such grave danger of extinction! The major threats that these species face are siltation, water pollution, damming or conversion of streams, and the presence of invasive mussels (zebra mussels). Wisconsin is home for 51 species of freshwater mussels and 33 of those are considered endangered, threatened or rare enough to be of special concern. Only 18 species currently have healthy populations.

Jesse Weinzinger with fellow UWGB graduate student Chelsea Gunther at the Wisconsin Wetlands Association Meeting.

Jesse Weinzinger with fellow UWGB graduate student Chelsea Gunther at the Wisconsin Wetlands Association Meeting.

UW–Green Bay graduate student Jesse Weinzinger is on a mission to better protect Wisconsin’s freshwater mussels, one of North America’s most diverse and ecologically important aquatic species. Mussels are ecosystems engineers that filter nutrients and particles improving water quality downstream. They also stabilize stream bottoms and provide habitat and food for fish and mammals.

Jesse uses a mask and snorkel to monitor mussel populations.

Jesse uses a mask and snorkel to monitor mussel populations.

The Wisconsin Department of Natural Resources, along with the help of university researchers and citizen scientist volunteers, are surveying mussels in streams to learn more about the lifecycles and population structure of these important animals. However, the current survey protocol is very labor intensive and the state lacks the funds and staff to maintain long term monitoring efforts. Jesse is investigating ways to make the monitoring of Wisconsin’s mussels faster and easier. He is working with the WI DNR to establish a rapid assessment protocol for volunteers of the Mussel Monitoring Program of Wisconsin. The end result will be an efficient, teachable, and easy-to-use protocol that will provide new volunteer opportunities and, if the method is applied successfully, results will provide rigorous quantitative data to inform the DNR as it makes management decisions.

Jesse’s research is partly supported by grants from the Heirloom Plant Sale Fund and from the WI DNR.

How can you help? Become a mussel monitoring volunteer!

Wisconsin Shamrocks!

Did you get a shamrock plant for Saint Patrick’s Day? It was most likely one of a few species in the genus Oxalis. Over 800 different species of Oxalis occur throughout most of the world, especially in Central America and South Africa. Their common name wood sorrel or in Europe wood sour refers to high concentrations of oxalic acid in the leaves and stems. Some are cultivated for their nutritious rhizomes, especially acta (O. tuberosa) in South America. Others like candycane sorrel (O. versicolor) and purple shamrock (O. triangularis), are prized by florists and gardeners because of their showy leaves and flowers and it is likely that you received one of these.

But is Oxalis “the” shamrock? According to Bess Lovejoy writing for, nobody is sure what plant species the stylized 3-leaved shamrock represents. Some, like 19th Century British botanist James Ebenezer Bicheno claimed that wood sorrel (Oxalis acetosella) was the “true” shamrock. Perhaps unconvinced that the British would best know which plant the Irish should call shamrock, Dublin native and amateur botanist Nathaniel Colgan decided to conduct a poll in 1892. He had people from different counties in Ireland send him specimens of shamrocks they had collected. Although there were no single winner based on his results, it seems that the Irish favor a few species of Clovers (Trifolium) especially white clover (Trifolium repens). Botanist E. Charles Nelson, repeated the study in 1988 and found similar results. Although most people selected among several species of clovers, about 5% of participants selected Oxalis as their shamrock.

Oxalis acetosella f. montana

Wisconsin’s Shamrock (Oxalis acetosella f. montana)

White clover is common in our region especially in agricultural and other grassy open fields, however, it is not native and can be invasive, so we are choosing one of our native species of Oxalis, the northern wood sorrel (O. montana or O. acetosella f. montana), as our symbol of the season. The plants are still hunkered down as underground rhizomes, but you will be able to find these forest plants blooming throughout the western Great Lakes region in June. Look for it in boreal and mixed evergreen-deciduous forests or in northern maple beech hardwood forests.

We have several bright yellow flowered Oxalis species in WI which are somewhat associated with disturbed sites, and only two white to pale purple/rose flowered species as in O. acetosella. There is a similar species in southern WI called the violet wood sorrel (O. violacea). The two species are almost perfectly segregated geographically in the state—SW dry and sunny (violacea) versus NE moist to wet and forested (acetosella f. montana).

By Vicki Medland and Gary Fewless

Read more about the history of shamrocks in Smithsonian Magazine online:

Spiders in Search of Beachfront Real Estate!

Dr. Michael Draney (Natural and Applied Sciences) and James Steffen (Chicago Botanic Garden) recently published an article in the journal Great Lakes Entomologist titled “Disjunct Lake Michigan populations of two Atlantic Coast spiders, Disembolus bairdi and Grammonota pallipes (Araneae: Linyphiidae)”.

Steffen and Draney discovered two species of spiders living on the beaches of Lake Michigan that had only ever been found before living near the Atlantic Ocean. Scientists use the word “disjunct” to describe isolated populations like these that are related but widely separated from each other geographically. The discovery that the spiders also live along the shore of Lake Michigan, more than 800 miles inland raises some interesting questions, namely how did these very tiny (less than 2 mm animals) get to the Great Lakes across hundreds of miles of unsuitable habitat?

Populations can become separated from each other when the environment they live in separates into fragments due to geologic or climate events. Continents drift apart, rivers change their course or mountains rise, isolating populations on separate islands of suitable habitat. Populations also become disjunct from each other when species expand their ranges into new territories. This most often happens with species like birds or butterflies that can move long distances, or with species that hitch a ride on floating debris or on (or in) migrating animals.

Beach habitat

Beach habitat.

Can you tell which of the photos is of a beach on Lake Michigan and which is a beach in New Hampshire?

(See the end of this post for the answer.)

While we don’t know how they got so far away from the Atlantic Ocean, the most probable explanation is that individual spiders ballooned inland by releasing long gossamer threads of silk that catch the wind and propel them along like a kite. Ballooning spiders are known to travel even thousands of miles using this technique. Those that were lucky enough to land near the shore of the Great Lakes found themselves in a hospitable and familiar habitat that they could colonize. The spiders do not care where that beach is located as long it provides what they need to survive and reproduce. Suitable habitat probably exists or existed in patches along the St. Lawrence Seaway and the Great Lakes east of Lake Michigan, and spiders may have “island hopped” by ballooning between such somewhat isolated islands of suitable habitat along the way from the Eastern Seaboard to northern Illinois.

Understanding more about disjunct populations like these helps us to understand how specialized species might fare as they become isolated. Under favorable conditions, isolated populations survive, and over time, due to mutation and natural selection, become so genetically different from their far away relatives that the population may evolve into a new species. When conditions are poor and habitats are degraded or lost to development, pollution, or climate change, small isolated populations are more likely to go extinct. By monitoring species like these we can better track the health of the Great Lakes.

Essentially all of the midwest’s plants and animals were absent from the Great Lakes thousands of years ago when the region was glaciated.   Each species has a different history of where it took refuge during those ages, and how it got from there to here.   The intersection of all these unique natural histories contributes to our complex and fascinating regional biodiversity. These Atlantic coast disjuncts are here because of the Great Lakes and the unique coastal habitats they make possible. The present study shows that not just plants (like dwarf lake iris or Pitcher’s thistle) but also animals can be dependent on special Great Lakes coastal habitats. You’ve probably never seen Disembolus bairdi and Grammonota pallipes. Still, these species are two additional (but tiny!) reasons to appreciate our Great Lakes.

The photo on the top was taken by Dr. Robert Howe at White Fish Dunes, WI and the photo on the bottom was taken by Dr. Steve Weeks of dunes in New Hampshire.

A walk in the Cofrin Arboretum

It is still beautiful in the Cofrin Arboretum. Take a walk before the trees are bare!


If birds summering in the Western Great Lakes region have a favorite fruit, it has to be the Juneberry (Amelanchier spp.). Two weeks before the fruit were ripe our resident American Robin would make a daily visit to the trees outside my office, hop from branch to branch, cocking his head to get the best eye-full of berry.  He would sample ones that had already brightened to rosy pink, sometimes dropping the fruit if it was too green. On the day the first fruit ripened, she had the tree to herself for about 3 hours before the first Cedar Waxwings arrived. At the height of the harvest on the single tree, I counted one adult Robin, three juvenile Robins, 8 Cedar Waxwings, a pair of Northern Cardinals, and one shy Grey Catbird that was immediately chased off by the Waxwings.

Cedar Waxwing and American Robin feed on Serviceberries

Cedar Waxwing and American Robin feed on Juneberries

I usually cannot help myself, and sneak out to pick a handful of the fruit for myself. The flavor is reminiscent of blueberries, but has definite plum or dark cherry flavors as well. A serving of juneberries provides 23% of  the recommended amount of iron and are high in potassium, and magnesium, vitamin C, B6, A and E.  Cooking the berries improves the sweetness and flavor of the fruit, so feel free to eat that whole juneberry pie!

There are 20 named species in the genus Amelanchier (Rosaceae). There are almost as many common names to describe these shrubs and small trees  including juneberry,  shadbush, shadwood, shadblow, serviceberry or sarvisberry, wild pear or chuckley pear, sugarplum or wild-plum, and even chuckleberry, currant-tree, or saskatoon.  In the southwest, Amelanchier denticulata is referred to as Membrillo, Membrillito, Madronillo, Cimarron, Tlaxistle, or Tlaxisqui. The common names often vary by location and many relate different phenological events together. Juneberry is obvious, and is most often used for the species that occur in the Midwest where the berries usually ripen in June, (however this year they did not ripen in Green Bay until July 2nd).  Several names refer to the flavor or shape of the fruit including membrillo, which is Spanish for quince, or to location, such as Saskatoon or Cimarron.  Names that include shad are derived from New England and eastern Canada, where the shrubs bloom in early spring at about the same time that Shad (fish in genus Alosa) return to rivers to spawn. Service or “Sarvis” supposedly relates back to the time of itinerant preachers that traveled in New England. The plants bloom in early spring shortly after the trails are clear of snow and the preachers were able to travel to the towns. I could find no source for chuckleberry, but it seems likely a corruption of the older chuckley pear, another name that I could find little history on.

Amelanchiers are important plants for native landscapes. These shrubs provide nectar for early emerging pollinators especially native bees and overwintering butterflies, fruit for birds, and are hosts for the larvae of several species of butterflies. The plants provide four season interest, including beautiful white flowers in early spring, berries in early summer, foliage that that turns to brilliant oranges to deep reds in fall, and beautiful vase shaped silver barked stems in the winter.  There are a variety of forms available to suit most areas from small shrubs to branching specimen tree that can grow to 25 feet in height. The eastern varieties are understory shrubs that are well suited to woodland or shady areas. And if you are lucky and can beat the birds to harvest, the sweet fruit can be used in almost any recipe that calls for blueberries.

Flowers, form, and berries of Amelanchier laevis, a common serviceberry in Wisconsin and the eastern United States. Other species have similar flowers and fruit.

There is at least one species of Amelanchier that is native somewhere on mainland North America and all species are edible, so it should be possible to find a variety that will thrive in your yard. Native varieties should be available at specialty nurseries and many nurseries carry the Apple Serviceberry (Amelanchier X Grandiflora), a hybrid between Amelanchier canadensis and Amelanchier laevis that grows 15 to 25 feet tall and has large showy flowers. There are several named varieties with different growth habits, fall coloration, and disease resistance.  “Autumn Brilliance” is one hybrid variety that is most readily available in the Midwest. All species are edible, although some produce more or larger fruit and new disease resistant horticultural varieties are now available that make growing these plants easy for home gardeners.


More information and Recipes

A Winter Filled with Finches

Wisconsin birders are looking forward to an excellent finch winter! 

Birds that usually winter in Canada are moving south. These atypical “irruptive migrations” are usually caused by changes in winter food availability and can occur in several northern species especially finches, owls and evening grosbeaks. This year finch species that normally winter in Canada and the northern United States are ranging farther south due to a massive crop failure of fruit and cone bearing trees in Canada.  Birding expert and Ontario resident Ron Pittaway compiles local seed crop and late summer bird observations to create a detailed “Winter Finch Forecast”  available through Ebird every autumn. The Wisconsin Ebird group uses the Pittaway data to create detailed forecasts for our area. Based on the two forecasts we should expect to see Red and White-winged Crossbills, Redpolls, Pine Grosbeaks, Pine Siskins, and Evening Grosbeaks joining resident Goldfinches, House and Purple Finches this winter in northeastern Wisconsin.

Pine Grosbeak photo by  Tom Prestby

Pine Grosbeaks are large finches with heavy black bills and gray sides and red washed black back and reddish pink rump.

Pine Grosbeaks have been steadily moving into the state in small flocks. Look for them on the UW—Green Bay campus feeding on crab apples, especially near the Kress Center. This is a taiga species which is considered an irruptive winter visitor across the Midwest and east.  The last really large widespread movement into Wisconsin was in 1977 and again in 1985. They love to dine on crabapples, high bush cranberries, left over apples in orchards, sumac, mountain ash, and when food supplies are exhausted, the seeds of the box elder ash. Pine Grosbeaks will also switch to backyard feeders when black sunflower seeds are offered, but for now, it is find the fruit trees first!!

Evening Grosbeak photo by Tom Prestby

Evening Grosbeaks are striking birds, identifiable by their large pale bills and black, white, and bright yellow coloration.

Evening Grosbeaks have been on the decline in Wisconsin in recent years and are usually only seen reliably in the far north of the state. Evening Grosbeaks nest as close as Lakewood, Oconto County, annually. However, based on arrival data, the birds being seen now are coming from the northwest. Observations were reported from Duluth as birds rounded Lake Superior. So far this year there are a few reports in Oconto, southern Brown, and Manitowoc counties.  Their preferred seeds are box elder and other maple species. They will also visit platform feeders supplied with black oil sunflower seeds.

Red and White-winged Crossbill species have staged a massive irruption into Wisconsin. Although these birds are unlikely to come to backyard feeders, look for them in conifer swamps and bogs in the far North, the Green Bay area, and in conifer groves along the Lake Michigan Lake shore from Manitowoc down to Chicago. Interestingly, according to Ebird, the Red crossbills arriving in Wisconsin are from western Canada escaping a hemlock seed crop failure in the Pacific Northwest.

Common Redpolls, Pine Siskins, and Goldfinches are common winter residents throughout northeastern Wisconsin and while abundant are not occurring in higher than expected numbers. Purple Finches have apparently moved on and are now below expected numbers. House Finch populations are way up after declining for a number of years. These birds prefer small seeds including birch, alder, willow, tamarack, and weedy field forbs. They will visit backyard nyjer (thistle) and black oil sunflower seed offered in feeders.

Two non-finch species are also irrupting south in response to the seed failures in Canada.

Bohemian Waxwings, while not finches, are another fruit loving bird that is irrupting southward because of the Canadian fruit crop failure and are expected to appear in large numbers in our area this year. In fact a flock of over 250 Bohemian Waxwings seen in Door County was recently reported to Ebird. These birds are voracious fruit feeders so look for them in urban or natural areas with fruit bearing trees like mountain ash, Juniper, and crabapples. These assertive birds will compete with Pine Grosbeaks for access to fruit trees. Bohemian waxwings form pure flocks of their own species or in mixed flocks with Cedar Waxwings.

Bohemian Waxwings are very similar to Cedar Waxwings. Bohemians are larger and have black, yellow, and white wing bars.

Rose-breasted Nuthatches feed on conifer seeds and so are also arriving in high numbers from the same northern regions because of the cone failure. They are often seen at platform feeders eating sunflower seeds and also will feed at suet feeders.

Feeding Finches:

Ebird recommends that people hoping to attract winter finches to their yards put out platform or other large flat surface feeders with black oil sunflower seeds. All finches like small seeded sunflower seeds and some finches like Goldfinches, Redpolls and Siskins also will feed on nyjer in tube or bag feeders. Most finches are attracted to water, so maintaining a heated bird bath or water feature will bring birds to your yard.

It is going to be a very delightful finch winter. 


More Information:

  •  Tom Erdman contributed to the text and Tom Prestby provided photos


Biodiversity and West Nile Virus

2012 is the worst year on record for West Nile Virus (WNV) in the United States since the disease first appeared in New York in 1999. Forty-seven states, including all states in the Western Great Lakes have reported cases of both infected birds and humans and all 50 states have reported infected birds.

West Nile Virus is transmitted by the bite of a mosquito. While several species of mosquitoes can harbor the disease, the most common species we are likely to encounter in urban and suburban areas is Culex pipiens, the northern house mosquito. Culex and the other suburban mosquitoes prefer to breed in small containers or stagnant water with lots of organic debris like animal droppings or decaying leaves. The disease is transferred when a mosquito bites an infected bird. That mosquito can then pass the virus on by feeding on other birds, or susceptible mammals including humans.

Culex pipiens (Northern House Mosquito)

Culex pipiens (Northern House Mosquito), photo by G. Fewless

Unfortunately, the disease can heavily impact bird populations. Crows are particularly sensitive to WNV and populations in North America declined by as much as 45% after the WNV epidemic in 2002. Robin populations were increasing in the 1990s, but have leveled off since the introduction of WNV.

Increased biodiversity provides an advantage against infection. Scientists have shown that areas with more bird species tend to have fewer mosquitoes carrying WNV and fewer cases of human infections (Ezenwa et al., 2006; Swaddle and Carlos, 2008). Researchers believe the effect is related to the susceptibility of different bird species to the virus. Some birds like American robins are known to be good hosts and are better at spreading the disease because mosquitoes seem to like to feed on them and they are better carriers than some other species. According to Tony Goldberg, an epidemiologist at UW—Madison, robins are good hosts and can act as “super-spreaders” of the disease. In areas with lots of robins and few other bird species there are higher total number of human infections. But not all bird species are good hosts for the disease so it is thought that higher bird diversity reduces infection rates because mosquitoes are less likely to encounter a good host and therefore less likely to become infected and transmit the disease. The presence of birds that are poor hosts reduces or “dilutes” transmission rates of the disease between birds and also to humans. Similar results have been shown for other animal vectored  diseases like Lyme and Hantavirus (Keesing et al. 2010).

Controlling mosquitoes

  • Large ponds and healthy wetlands contain fish and invertebrate predators like dragonfly larvae that feed on mosquito larvae that naturally keep mosquito populations in check. The problem mosquitoes are those that prefer to breed in stagnant water like puddles, tree-holes, and other small containers.
  • Make sure you are not inadvertently providing mosquito breeding containers. Be sure to make sure your gutters are not clogged and that old tires or children’s toys or other containers cannot hold water.
  • Empty containers of water such as bird baths, kiddie pools, plant trays, twice each week.
  • Consider using mosquito dunks that contain Bt in yard water features that are too large to empty each week. The dunks contain the bacteria Bacillus thuringiensis Israliensis, which produces a toxin that kills mosquito larvae, but is non-toxic to other wildlife.
  • Where long sleeves and long pants and use CDC recommended mosquito repellants
  • Fans can be effective at deterring mosquitoes in a small area such as on a deck or a patio area. Mosquitoes are weak flyers and fans will keep them at bay. Fans also blow away exhaled carbon dioxide that attracts mosquitoes.

Increasing backyard bird diversity

  • There is no reason to stop feeding or watering birds because the disease can only be transmitted by the bite of a mosquito. The disease cannot be transmitted from bird to bird, from birds to people or from people to people.
  • Provide a variety of feeders and feeds that attract different species.
  • Create as much quality habitat as possible. Include vegetation, shrubs, and trees that provide forage and cover from predators.
  • Try to match natural habitats by planting vegetation that includes a diversity of plants and plant types.
  • Provide bathing and watering areas, but be sure to keep them mosquito free.
  • Keep your feeders and feeding areas clean to prevent the transmission of bird diseases. There are no known cases of West Nile transmission between birds in nature, but stressed, injured, or birds sick with other diseases will be more susceptible to West Nile infection from mosquitoes.


Ezenwa, V.O. et al. 2005. Avian diversity and West Nile virus: testing associations between biodiversity and infectious disease risk. Proceedings of the Royal Academy: Biological Sciences 273:109-117.

Kessing et al. 2010. Impacts of biodiversity on the emergence and transmission of infectious diseases.    Nature  468: 647–652

Swaddle JP, Calos SE (2008) Increased Avian Diversity Is Associated with Lower Incidence of Human West Nile Infection: Observation of the Dilution Effect. PLoS ONE 3(6): e2488. doi:10.1371/journal.pone.0002488

Zimmer, C (2012) West Nile Virus: The Stranger that Came to Stay. Discovery Magazine “The Loom” Blog.