Wisconsin Natural Resources magazine

Wisconsin Natural Resources magazine

Photo of warbler habitat © Andy Paulos

Lowland floodplain forestland with confirmed nesting sites of prothonotary warblers.
© Andy Paulos

December 2010

Readers Write

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Warbler Habitat

We've had lots of positive response to our story about enticing more prothonotary warblers to nest in Wisconsin (New kingdoms for little birds in golden robes August 2010). Several readers asked to see what good prothonotary habitat looks like and where the birds have been found nesting. Here's a photo of the lowland floodplain forestland and confirmed nesting sites. Find a range map at Wisconsin All-Bird Conservation Plan.

More "Wild Whodunits"

I saw the article "Wild Whodunits" online for the Wisconsin Natural Resources magazine. Once I saw what the article was about, I was hoping to see my favorite author listed with the rest.

Nicholas Evans (the author of The Horse Whisperer) also wrote a few gripping tales that involve natural resources professionals. One is called The Divide and is about a young woman's personal struggle to figure out which kind of environmentalist she is – a hippie or a hunter? He wrote The Smoke Jumper, which is about a fiery love triangle (pun definitely intended!) between a man, a wife, and the man's best friend. The two men are smoke jumpers in the western states and the woman is a type of backpack boot camp counselor. And the other one that instantly came to mind is The Loop, about a U.S. Fish and Wildlife biologist who gets called out to a tough Montana town to research and protect the wolves against the very people whose hospitality she has come to rely on.

All are fantastically written, must reads on my list! I would highly recommend them to any conservation-minded individual looking for a serious "page turner" to use the old saying. Maybe not "whodunits" but certainly beautifully sculpted novels (and that's coming from a bit of a book critic!).

Thanks for the recommendations!

Caitlin Carmody
Madison

What a surprise treasure trove of books – the "Wild Whodunits" in your August magazine.

I've long been a Nevada Barr fan and now I'm anticipating many months of enjoyment – especially if we get snowed in this winter. I enjoy the whole magazine, but this is a real treat!

Mrs. Ron Schroeder
Rock Island, Ill.

Warbler Nest Boxes

Excellent article on prothonotary warblers. I received three of the nest boxes and provided one to a couple who had been putting up milk cartons so they would have this sturdier design. I erected my two nest boxes in Columbia County east of Wyocena on a branch of Duck Creek. One box had a wren nest and the other was empty. We'll place the boxes in the same location next year.

Mark Martin
Arlington

Bat Diet

In your story Going to Bat for Bats (August 2010) there's a reference to the number of insects consumed annually by one million bats equal to a staggering 694,456 tons. Can you double-check those numbers? If true, they are indeed staggering and hard to believe. That would equal about 1,348 pounds per bat annually and nearly 3.8 pounds per bat per day. That seems unlikely given that the common North American bat weighs only about an ounce.

Doug Carlson
Eau Claire

Bat Ecologist David Redell responds...

You're right! Testimony by Boston University's Professor Thomas H. Kunz before a congressional subcommittee on white-nose syndrome estimated insect consumption at 694 tons by a million bats. Translated to the number of insects eaten by one little brown bat in your backyard on a given night amounts to the equivalent of 60 medium-sized moths or up to 1,000 mosquito-sized insects. So losses from white-nose syndrome significantly reduce insect control by bats.

Doe-to-Doe Contact is a Key CWD Transmission Route

Close contact among adult female white-tailed deer in Wisconsin appears to be a more important route of transmitting chronic wasting disease (CWD) than environmental contamination. As a result, CWD management should consider harvesting does and doe fawns to keep female social groups small and reduce doe-to-doe interaction.

That's one of the findings in a research study – "Influence of genetic relatedness and spatial proximity on chronic wasting disease infection among female white-tailed deer" – led by Prof. Mike Samuel of the U.S. Geological Survey's Wisconsin Cooperative Wildlife Research Unit at UW-Madison.

"Social organization and interactions among does are suspected to play important roles in transmitting and potentially managing wildlife diseases and does interact with other closely related does more than any other deer," notes Samuel.

CWD is a fatal nervous system disease that belongs to the family of transmissible spongiform encephalopathies (TSEs) or prion diseases. Though it shares features with other prion diseases, like mad cow disease in cattle and scrapie in sheep, CWD is known only to affect members of the deer family (white-tailed deer, mule deer, moose and elk).

Samuel and the team of researchers used genetics to ascertain how does were related and whether direct deer-to-deer interaction between these closely related females is an important route of CWD transmission.

"Mitochondrial DNA is only inherited from the mother, so it can be separated from the father's DNA and enables us to identify first-generation female relatives (mothers and daughters or sisters)," says Samuel.

"Females cluster on the landscape and don't move a lot compared to males. Female fawns typically live near mom where they interact a lot with their close relatives, smelling and grooming each other," points out Samuel.

"Such closely related kin have more contact, higher frequency and intensity of interaction and greater spatial overlap" when compared to less related females, according to Samuel.

Hunter-harvested deer from the 210-square-mile "Core Area" of western Dane and eastern Iowa counties were examined in the study. CWD prevalence (percentage of infected deer) and deer density are highest in the Core Area. The group analyzed 1,387 adult females, of which 77 (5.5%) tested positive for CWD and 1,321 adult males, with 99 (7.5%) testing positive. Using regression models, the researchers found that the odds of CWD infection in adult female deer increased 138-fold in first generation adult female deer. The results are published in the Journal of Applied Ecology.

What does it mean?

The group's research, from a CWD management and field perspective, points toward a continued emphasis on harvesting female deer.

"Given that our data demonstrate a strong relationship between infection probability and female relatedness, CWD management should consider harvesting females to maintain smaller female social groups and reduce contact among females. Evaluating the effects of this strategy on deer social behavior and contact is needed," advises Samuel.

One way to harvest more females is to keep Earn-a-Buck (EAB) in the agency's CWD management tool box. Under EAB, hunters must first shoot an antlerless deer before they can harvest a buck during both the bow and gun seasons in the CWD Management Zone of southern Wisconsin.

Members of the research team and authors of the paper are Daniel Grear, UW-Madison graduate student who conducted the project, Kim Scribner, Michigan State University, Byron Weckworth, University of Calgary, and Julie Langenberg, Wisconsin Department of Natural Resources.