Nature Blog | Woodland Dunes Nature Center and Preserve

Ripples 2/6/20

Posted on February 7, 2020 by Jim KnickelbineFebruary 7, 2020

Last December, as I was crossing the yard at the nature center I heard an unusual bird song. It came from a small songbird perched near the top of an ash tree west of the barn, overlooking a brushy area. After retrieving binoculars from my car, I could see that the bird was gray with dark wings and a long tail- a shrike. Later, another showed up in the neighborhood in which I live.

Northern shrike

The fact that the song was so unusual is not surprise- although shrikes visit our area in winter, there are never very many of them around.

Shrikes are very interesting birds in that they’re called predatory songbirds. They feed on mice and voles, small songbirds, and large insects. They are intelligent enough to plan ahead when it comes to ensuring a constant food supply- when prey is abundant they catch more than they need at the moment, and store the excess for later. They do this by impaling the bodies of their victims on thorns or even barbed wire, hanging them as if in a miniature old-time butcher shop. For that they were given the nickname “butcher bird.” Unfortunately, to some the term implied that the birds were somehow overly vicious, but that is hardly the case. In reality, many birds are omnivores and incorporate other animals into their diets. Robins eat many invertebrates when they are available, and I wouldn’t want to be a caterpillar on a branch where a chickadee had landed. My favorite representation of this was in the movie “A Bugs Life,” where, to the insects who were the main characters of the story, a cute, fuzzy canary was what they feared most.

There are actually two species of shrike that can be found in Wisconsin and which are nearly identical in appearance – the loggerhead shrike, which is rarely present in summer and sometimes nests here, and the northern shrike which migrates south to our area in winter. The northern is the only one seen in winter and is much more common. It nests far to the north, in the spruce forests and even arctic tundra. It makes a very deep cup-shaped nest in which it lays a half dozen grayish to greenish splotchy brown eggs. Much of their nesting area in Canada and Alaska has been protected, and even though they are not common birds here in winter, their population appears to be stable for now- a warming climate may change habitat in the hooknorth.

Shrikes lack the talons of the hawks and owls. Their feet are like those of other songbirds, and they don’t rely on them to grasp and suffocate prey as do the raptors. Rather, shrikes pursue and hit their prey with their sharp hooked bills. They knock prey to the ground, then use their bills to sever the spine of their victims behind the head. I have never caught and banded a shrike, but I am told that they can deliver an especially nasty bite to the hand of a bander.

Its hard to think of Wisconsin as a place to go to spend the winter, but shrikes and some other birds do exactly that. Unlike some of the owls which are forced here during certain years when food is scarce, shrikes and other predators like the rough-legged hawk are regular visitors from the Arctic and may be better adapted to the long migration. They provide unexpected surprises for birdwatchers, and unexpected drama around bird feeders at times as they pursue small birds. Like many of the 300 or so species of birds found in our Lakeshore area, they lend variety to the experience of observing nature, and elevate our quality of life.

photo- northern shrike By Paul Hurtado – Northern Shrike, CC BY-SA 2.0

Ripples 1/30/20

Posted on January 31, 2020 by Jim KnickelbineJanuary 31, 2020

I remember looking out at the birdfeeder and seeing it crammed full of evening grosbeaks- large black and yellow finches with large bills. They reminded me of big wasps in a way. They would show up in the coldest part of winter in flocks of dozens to hundreds of birds, chirping loudly. Bernie Brouchoud used to band them here and in Manitowoc in the winter, and would have bird feeders made out of doors to accommodate all the birds. At that time it was more common to see other winter finches- pine grosbeaks, redpolls, crossbills, and pine siskins. We still see some of the latter species, but not as much- its been several years since we last saw redpolls, crossbills, or pine siskins at our feeders.

Between 1988 and 2006 Cornell University’s Project feederwatch documented a 50% decline in evening grosbeaks. Recently, this was revised to an estimated 90% decline using the latest data. And there are four other species that have experienced declines from 86% to 89%, including the bank swallow, which nests around here.

Recently there’s been news about the recovery of bald eagles- nearly 1,700 nests are known in Wisconsin in 71 of 72 counties. In their case removing one pesticide from the environment helped that species recover. In the cases of the birds listed above, the causes of their declines are not so obvious. For evening grosbeaks, there may be a number of factors involved. The American Bird Conservancy lists destruction of large areas of habitat in Canada, changes in tree populations, and a warming climate (which might make life more difficult for birds of the far north). Believe it or not, evening grosbeaks benefit from boxelder trees – the females of which produce loads of seeds. As our forests mature, boxelders thin out of the forest. In Canada, spruce budworms are an important food source, but at the same time a major pest of coniferous trees such as spruces. People spray large areas to kill them, which harms birds and reduces their food source, something that has been surmised for other species of that habitat as well.

A bird that nests around here that unfortunately made the list is the bank swallow. These small brown and white birds nest in holes they excavate in the sides of sand or mud banks or mounds. They are also susceptible to disturbances in those areas during nesting season and to pesticides which contaminate the insects they feed on.

I wish that helping nature was simple, but doing so is as complex as taking care of your own health. There’s no one thing that we can do to manage everything that can go wrong with our own bodies. We have to eat in a healthy way, exercise, avoid excessive chemicals… a lot of different strategies. I hope that we can determine the right mix of actions before we lose some of these beautiful birds completely.

photo by By Cephas – Own work, CC BY-SA 3.

Ripples 1/23/20

Posted on January 24, 2020 by Jim KnickelbineJanuary 24, 2020

It is a beautiful, soft morning, with light wind, gray skies, and light snow falling. Even though it’s January, it’s not terribly cold. There is open water on the Manitowoc River where it flows fast, and dozens of chickadees are already singing their courtship songs (sounds like a whistled “cheeseburger” call). Winter is racing along – in a little more than a month it will be March.

To the south, the earth is waking up- wildflowers are blooming in Tennessee already, earlier than normal, and birds are either nesting in the southern US or becoming fidgety in anticipation of the coming migration. Here we must wait for those signs of spring yet. We all know February and March can be tough months to weather sometimes.

As far as bird migration goes, we are planning for this year’s strategies to document the birds which either return to or pass over our Lakeshore area in and around our nature preserve. We now use four different methods to do so:
1. Point counts- our staff and volunteers (thank you, Darlene!) go to preselected places and for 10 minutes count every bird they see or hear. These are done once per week during times of migration.
2. Traveling counts- preselected routes are walked and birds recorded. We do some of these at Woodland Dunes, and they are done daily by Charles Sontag at the Manitowoc lakefront.
3. Bird banding- probably the first activity at Woodland Dunes, tens of thousands of birds have been caught, banded, and released so that their movements and lifespans can be documented.
4. Telemetry- using the Motus system and antennae to detect radio-tagged birds.

Woodland Dunes is one of just a few facilities in the State to install a Motus detector, along with the Western Great Lakes Bird and Bat Observatory near Port Washington and some near Chequamegon Bay on Lake Superior. Motus was developed in Canada by researchers who track movements of birds and bats and were looking for a way to do so that is less costly than some older methods. Although there are only two in Wisconsin, there are hundreds of stations in Canada and the eastern United States. For Motus, birds are caught in the same way we do during banding. Small transmitters are placed on the bird in a way that doesn’t hinder their movement. Transmitters have batteries which last anywhere from a few weeks to several months. The bigger the transmitter “tag” the longer the battery life, but large tags are only suitable for large birds. The smallest tags, however, can even be used for large insects like dragonflies and butterflies. Some researchers use them to track bats, and one is proposing a study using tags to follow the movements of turtles within a nature preserve. Even though the cost is lower than some other systems, tags are still about $300 each, which limits what places like Woodland Dunes can do.

The Motus array has two components- three antennas which are pointed so that they can record signals over a wide area, and a small computer which detects signals and stores the data. It takes some technical expertise to set up the system and make sure the computer is talking to the antennas- I am grateful for the help of people who are much more skilled than I for set up. Once deployed, the system passively listens for signals from the transmitters of tagged animals which pass by. Our Motus unit was installed late last summer, at the start of the fall bird migration. Recently, we went to recover data from the receiver, and found that three birds had been detected.

The first and second were both Swainson’s thrushes, which nest in the far north woods and which were both tagged in British Columbia! We know that Swainson’s are abundant during migration here each fall, and follow the south edge of the Canadian forests eastward to the Great Lakes and then turn south. Over the years, they have been the second most commonly banded bird in fall at Woodland Dunes. Eventually, they move down to Central America for the winter- a journey of thousands of miles. One of these was also detected in Saskatchewan on its way here.

The third bird was a Virgina rail, a fairly common but seldom seen bird of marshes. This one was tagged in Ohio, and was detected at a number of different locations including the Bird and Bat Observatory in Port Washington. With all that wandering, one wonders what the bird was looking for.

This is a critical time to research and try to understand birds. They are facing increasing challenges, and many are declining in numbers before we even understand why. The corridor including Lake Michigan is an important migratory area, but there is still much that we need to learn. Now that we’ve added telemetry to our bird monitoring activities, we are sure to develop a better understanding of the unseen travels of creatures all around us. And use that knowledge to help them.

photos- Motus antennas and receiver unit

1/16/20 Ripples

Posted on January 17, 2020 by Jim KnickelbineJanuary 17, 2020

This morning, despite wind and 13 degree temperatures, an optimistic house finch sang his courtship song. Yesterday, out on the prairie on Woodland Drive, a rough-legged hawk sat perched in an ash tree. Where birds are concerned, it seems that there is something new happening every day, even if it just involves the birds we see at our bird feeders.

A lot of people realize this. A 2016 study by the US Fish and Wildlife Service indicated that 45 million people watch birds in this country, and spend 41 billion dollars on related activities, generating 660,000 jobs. In Wisconsin, there are many local bird clubs, and a Statewide organization, the Wisconsin Society for Ornithology (WSO). In addition to the birdwatching people do on their own, there are many guided field trips around the State, along with programs and other events.

Birdwatchers usually record their observations and participate in bird counts year round. They are, as far as I know, the first and largest groups of citizen-scientists, and their millions of observations contribute to a better understanding of not only birds but biology in general. These kinds of observations have documented some big changes in how birds migrate and where they live, probably influenced by a warming world.

Our Lakeshore is an outstanding place to see birds. Our combination of shoreline, forest, and grassland habitats makes it possible to see hundreds of species over the course of the year. At the lakefront alone, more than 300 species have been seen- as many as you would expect to see in the entire state in a given year. So sooner or later, birdwatchers find their way here to discover what we have had all along. And it’s the mission of Woodland Dunes to not only manage our preserve, but teach about nature, birds included.

Next May, the Wisconsin Society for Ornithology will hold their annual convention here May 14-17. Birdwatchers will come to experience the birds that live or migrate here through a number of programs: hikes, field trips by car, kayak, and bicycle, and more. Awards will be given and a banquet will be held over the course of four days. Concurrently, Woodland Dunes will hold it’s annual Migration Celebration and Bird Breakfast, which will include bird walks and activities for people of all ages and is open to the public.

If you are interested in learning more about birds from some of the most knowledgeable people in the State and the upcoming convention, you can find more information at wsobirds.org <http://wsobirds.org>

We look forward to being a part of the WSO convention, and sharing our wonderful birds with birdwatchers from throughout the region.

Photo: Birdwatchers at Woodland Dunes by Nancy Nabak

Ripples 1/9/20

Posted on January 10, 2020 by Jim KnickelbineJanuary 10, 2020

As I write this it is another gray, windy day with waves pounding the shore along Memorial Drive and lakeshore flood warnings are in effect. With lake levels so high, it doesn’t take much for such warnings to be issued. The wind seems to be stronger than it used to be, but I can never be sure my memory is accurate.

The average wind speed in Wisconsin is 12 mph. It can vary considerably across the state – today it ranges from 3 mph in the west-central part of the state, to 23 mph in our own back yard. That we are close to Lake Michigan, where wind can flow unimpeded, I’m sure contributes to velocities we see here.

What causes wind? Basically, the sun. Or the sun’s heating of the atmosphere, and water vapor that is evaporated and becomes a part of the air column. As a result of that, high and low pressure systems develop. Air flows from high to low pressure areas. The greater the difference between the pressures determines how fast the air moves, or how much wind is generated between the two. Lately, we’ve had some big storms in terms of that air pressure change – deep low pressure systems with a lot of wind every few days, sometimes developing in a very short time. We like to give those dramatic names like Polar Vortex or Bomb Cyclone- I don’t remember hearing those terms years ago.

Whatever the name, the wind affects many aspects of the outdoors. Birds migrate according to the wind direction and speed, sometimes riding the wind to very unusual places. Water on the ground evaporates faster. Lakeshore sand, cobbles, and even rocks are moved around, as is algae in shallow water. Trees in the forest come down, or are pruned by the wind. At the Nature Center, we avoid taking groups into the woods when the wind is greater than 20 mph for safety reasons. For the voyageurs who traveled along the shore by canoe, strong winds meant a layover until wind subsided – probably a much needed rest. Strong west winds still cause freighters on the Lake to seek shelter of the broad bay between Two Rivers and Manitowoc.

Among the most exposed wildlife are the diving ducks in the harbors and out on the Lake. I am amazed at their ability to withstand the cold and waves during winter storms. They move outward to avoid the breaking surf but are still subjected to wind, cold air and water, and large waves. They are well adapted to this part of their lives, with oiled feathers to shed water, extra down feathers to stay warm, and reduced blood flow to their legs and feet to avoid too much heat loss to the water. They have millions of years of adaptation to this life, and if they are able to stay in good condition can handle some really challenging conditions, as long as the water is open. Ice presents a different, and more severe problem for them, but that’s not the subject here.

Sometimes we experience wind without the rain or snow that storms bring – the precipitation is often not far away but not right on top of us. And sometimes the wind precedes the storm by several days. Our former Director, Bernie Brouchoud, used to say that storms would persist for the same length as the east winds that came before them. Whatever the duration, when I step out and experience the chill of the wind, I’m happy not to be one of those little ducks experiencing it full force out on the icy water.

photo- red-breasted merganser, a Lakeshore diving duck, from Wikipedia