Jim Williams has been watching birds and writing about their antics since before "Gilligan's Island" went into reruns. Join him for his unique insights, his everyday adventures and an open conversation about the birds in your back yard and beyond.

Construction details

Posted by: Jim Williams under Bird conservation Updated: October 6, 2014 - 11:28 AM

I’ve been in touch by email with an architect in New York City, partner in a large firm there, who has an interest in the Vikings stadium under construction because she believes strongly in bird-safe buildings. She gave me links to web pages that contained information new to me, which doesn't mean it's new.


One of the links was to the Minneapolis daily business newspaper “Finance and Commerce.” In late April it carried an excellent article by Frank Jossi that answers a couple of my questions. I also received information from the Minnesota Sports Facilities Authority.


I learned that 60 percent of the stadium roof will be made of a partly transparent building material known at ETFE (ethylene tetrafluoroethylene, a fluorine-based polymer). It comes in very thin sheets that will be used to form what you might call pillows, inflated by air pressure (but not subject to the puncture failure and collapse we saw at the old stadium). 


Jossi explained that the stadium will have glass 20-feet-wide at the top of its exterior walls, just beneath the ETFE roof. And there is the 200-foot-wide wall of glass on the stadium’s west side that is causing concern among birders. Maybe the 20-foot surround is regarded as a problem, too; I’ve not heard it mentioned in particular. But it is glass, and it does reflect. 


The figure commonly used for the amount of glass on the stadium’s exterior is 200,000 square feet. Actually, and this is the question the authority did answer, the amount is 180,000, not that that makes much difference.


There will be some pattern to the ETFE roofing material. It lets sunlight pass; that could cause a serious heat problem, a greenhouse effect. The material will contain two dot-matrix patterns, Jossi wrote, to block some sunlight and heat. Birders wish such patterns would be incorporated in the glass, to lessen reflection.



Rufous Hummingbird visiting

Posted by: Jim Williams under Bird identification, Bird migration, Bird sightings Updated: October 3, 2014 - 4:13 PM

A Rufous Hummingbird, breeder in the Northwest, has been coming to feeders in a yard near Le Sueur since Sept. 13. Mary and Steve Nesgoda have been hosts to the bird as well as about 240 birders who have come to their farmyard to see this unusual visitor. The bird is an adult male, only the fourth of that plumage documented in the state. Eleven immature or female birds also are on record. A friend and I saw the bird Friday afternoon. Rufous is the western species most likely to wander east in the fall. Given its habit of wandering in this direction it probably has a good chance of successfully reaching its wintering grounds along the Gulf coast. How long it will stay is a guess. Ruby-throated Hummingbirds also were seen at the Nesgoda's feeders. Identification books describe the bird's gorget -- its throat feathers -- as brilliant orange. I think sunlight would be needed to see that color, and Friday definitely did not offer sunlight.

List No. 3 -- birds difficult to see here

Posted by: Jim Williams under Bird identification Updated: October 2, 2014 - 12:02 PM

Here are the 10 bird species most difficult to see in Minnesota, migrant or resident, as chosen by Bob Janssen, the state's birding godfather. (Thanks, Bob.)

Harlequin Duck
Clark's Grebe
Little Blue Heron
Prairie Falcon
Piping Plover
Bell's Vireo
Mountain Bluebird
Smith's Longspur
Connecticut Warbler
Yellow-breasted Chat

NYC architect comments on stadiums, glass, and birds

Posted by: Jim Williams under Bird conservation Updated: October 1, 2014 - 5:09 PM

By Deborah LaurelPrendergast Laurel Architects 

New York City, 16 September 2014

As we approach the centennial of The Migratory Bird Treaty Act of 1918, enacted to make it unlawful to kill America’s native birds, threats to the future of many species are on the rise. Various communities across the U.S. have reached the conclusion that the time to employ bird-friendly building design has arrived. Meanwhile, new building construction is expanding with the population, and glass buildings have become ubiquitous. A Pilkington industry report notes that 6 million tons of glass was installed in North America in 2008 alone. Birds are facing a rapidly rising wave of hazard.

As an architect, I encountered the collision problem at completion of one of our projects when the director complained that birds were crashing into the windows. I began to work with Audubon, The American Bird Conservancy, architects, and scientists to identify alternative approaches to glass that can lower the risk of a fatal collision. Interestingly, our testing has shown that visible marks on glass, covering as little as 5% of the surface, can reduce collisions by up to 95%. In addition to marking glass with a permanent pattern, such as ceramic frit, lowering glass reflectivity is equally important. Just as there are many recipes for bread, there are many recipes for requisite energy coatings on glass. Among common architectural glass products, coating reflectivity ranges from 5% to a high of 40%. In simple terms, this highly reflective glass is coated with a mist of “silvered” metal oxides resulting in 60% transparency. As an example, Minnesota Audubon’s data on the specified glass for the upcoming Minnesota Viking’s stadium indicates 30% reflectivity, an alarmingly high rating. Add to this plans to include a new park adjacent to the mirrored windows of the stadium, and the results are predictable.

As a volunteer for New York City Audubon’s Project Safe Flight I saw firsthand the destructiveness of glass installed at buildings in Manhattan. I collected migratory bird species, such as the sunflower yellow Magnolia Warbler, and other birds that had all perished by flying toward the reflection of adjacent parks in the windows of the buildings I was assigned to monitor. Project Safe Flight offers instructive data for a building similar to the stadium, the Jacob Javits Convention Center. It is a large glass curtainwall exhibit hall that opened in 1986. The reflectivity of the original glass was 35%. In three months of Project Safe Flight monitoring during the fall of 2007, 75 collision fatalities were collected. Recently, the building skin was replaced with a mix of clear and dot frit glass with a low 8% reflectivity. Fall 2013 post-construction monitoring totaled only four fatalities, a 95% reduction!

The proposed stadium for the Minnesota Vikings, designed with 200,000 square feet of monumental glass walls, is an example of the grave threat posed by a reflective glass building. It is a fatal avian collision trap. Although Minnesota Audubon has approached the Minnesota Sports Facilities Authority with information on safer glass options, the Vikings have declined to revisit the stadium design.

Viracon, a Minnesota based company, supplied the glass for Javits, and they also will provide glass for the new Vikings stadium. Our inquiries with Viracon have revealed that glass similar to the stadium selection, but with much lower reflectivity, is available at negligible increase in cost. The addition of ceramic frit may add up to 20% to the glass material cost, but this is a tiny fraction of the myriad trade costs required to build a stadium. And frit adds long term benefits including energy-saving solar shading, as well as control of glare, that is desirable in a stadium. Just as there are many types of glass, there is a wide range of pricing.

Perhaps a bird-friendly selection can be identified for less than the $1.1 million cost cited. Structural steel erection has just begun at the stadium, so it may be 9-12 months before the windows are released for fabrication. That’s enough time to change course. The Minneapolis City Council has passed a resolution asking the Vikings to add frit to the glass. The State of Minnesota has a $498 million stake in the stadium, as part of a joint venture with the Vikings. Surely a prominent State appointed institution such as the Minnesota Sports Facilities Authority can find a way to join Audubon and initiate a change of the specified stadium glass.

Across the nation, changing our approach to glass is critical to the future of America’s native birds, such as the Ruby-throated Hummingbird, a species that is on the top ten list of window collision casualties collected in Minnesota.

Glass is what we make it. It’s time to make it safer.

(Used with permission of the author.)





Winter finch forecast

Posted by: Jim Williams under Bird biology, Bird feeding, Bird sightings Updated: September 29, 2014 - 10:52 PM


Each fall Ron Pittaway of Ontario gathers information on the tree-seed crops that will or won’t keep some of our hoped-for winter bird visitors north of us. From a variety of sources he collects data on three species of trees key to winter bird food — spruces, birches, and mountain ash trees.

Here is his forecast, with my disclaimer that things might not go exactly this way. Our thanks to him for this annual peak into the future at this winter’s feeders. 

One good piece of news is that cone crops are called poor west of Ontario, which might help birds in that region to move south.

Do not expect to see Pine Grosbeaks. Mountain ash crops are good in key Canadian areas. That is likely to keep these birds north.

We should see Purple Finches. They feed on seeds of coniferous and deciduous trees. Those seed crops are low. (Purple Finches favor black oil sunflower seeds at feeders.)

Red Crossbills are unlikely. Red and white pine cone crops in Ontario are good.

White-winged Crossbills are possible in areas where cone crops are strong.

Common Redpolls should return after an almost complete absence last winter. Birch seed crops are poor to average in Canada’s boreal forest. (Redpolls prefer niger thistle seed at feeders.)

Hoary Redpolls: watch for them in northern redpoll flocks.

Pittaway’s report says Blue Jays have been migrating south out of Canada.

Red-breasted Nuthatchs will be moving south because spruce cone crops, important to that bird, are low to average in number.

Bohemian Waxwings are predicted to stay north this winter because the mountain-ash berry crop throughout the boreal forest is very good to excellent.


Connect with twitterConnect with facebookConnect with Google+Connect with PinterestConnect with PinterestConnect with RssfeedConnect with email newsletters