Unusual Lake Michigan ice cover sends diving birds in search of conditions like those in city’s harbor
Florida, Arizona, southern California — these destinations look pretty good right now to Wisconsinites enduring more cold, snow and ice, but for a diverse mix of waterfowl, Port Washington is the place to be this winter.
Common goldeneyes, mergansers, scaups and long-tailed ducks have taken up residence, albeit temporarily, in the city’s harbor alongside the year-round Canada goose and mallard duck populations.
This is no vacation, however, for these visiting members of the duck family. This is survival during a frigid winter that has been hard on both man and beast.
“These species are very well adapted to cold conditions, but they can’t survive in the ice,” said Bill Mueller, director of the Western Great Lakes Bird and Bat Observatory at the Ozaukee Washington Land Trust’s Forest Beach Migratory Preserve in the Town of Belgium.
What’s remarkable, Mueller said, is not that these species of waterfowl are present in this area of Lake Michigan but the conditions they have had to deal with.
“These Lake Michigan species are present every winter, but what’s unusual this year is the huge buildup of ice on Lake Michigan,” he said. “This has caused a really dynamic redistribution of waterfowl in the lake. They are searching for whatever open water they can find.”
And that is what has brought them to Port Washington’s cozy harbor. Although at times this winter ice has covered far more of Lake Michigan than usual, at least parts of the harbor have remained relatively open in largely because of the warm-water discharge from the We Energies power plant.
“Where there’s warmer water and less ice, there will be higher concentrations of birds,” Mueller said.
Open water is critical for these species because they are divers, as adept at swimming as they are flying. Much of their time in the harbor is spent diving for fish and vegetation.
So voracious is the appetite of some birds during a winter when food is hard to come by that local fishermen report they can no longer fish with minnows because mergansers will dive for their hooks and pick them clean.
“This year, I can believe it,” Mueller said. “Normally, I wouldn’t expect them to do that. But the conditions this year are forcing birds to do things they usually wouldn’t.”
One of the things waterfowl are doing this year is putting on a lot of miles. There may be 15,0000 birds in the Milwaukee harbor one day and none the next if the temperature drops or the wind blows the Lake
Michigan ice pack ashore, said Mueller, who is participating in a federally funded survey of Lake Michigan waterfowl.
“Imagine you’re a goldeneye with 1,000 of your flockmates in the Port Washington harbor,” Mueller said. “It’s midnight, the temperature is dropping and you can sense the ice forming around you. It’s time to take off,
and just like that, you’re gone. Waterfowl just can’t take it easy this time of year.
“It’s confusing this year. We don’t know what to expect from one day to the next. It’s really dynamic.”
Changes in the Lake Michigan ecosystem are also influencing the distribution of waterfowl, Mueller noted. For instance, the long-tailed duck was once prevalent in the waters off Milwaukee and Ozaukee counties, but as
their food source, a form of zooplankton, has become more scarce because of competition from invasive species such as the quagga and zebra mussel, it has moved north.
This winter, however, the duck will go wherever it can find open water.
“This is not a bird that typically comes in shore, but we’re seeing a few now because of the ice on the lake,” Mueller said.
It all sounds pretty rough for the birds, but there’s an upside for the people who have had to endure the harsh winter.
“We’re lucky that these birds are closer to shore than normal,” Mueller said. “People are getting a better look at these species than they normally might.”
A RED-BREASTED merganser, one of several species of diving birds that has been seen in Port Washington this winter, rested between dives in the open water of the harbor last week. Photo by Bill Schanen IV