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Wisconsin Natural Resources magazine

Wisconsin Natural Resources magazine

April 1997

Readers Write

Cats as Predators

On the prowl identified rural, roaming cats as contributors to songbird decline. I am not minimizing that cats may be significantly preying on songbirds, however we also need to focus attention on the cowbird (Molothrus ater).

On a recent public TV documentary on songbird decline I was shocked to learn cowbirds may be responsible for more than 70 percent of the reproductive losses of songbirds. Development and clearing of deep forest habitat has opened up more songbirds to cowbirds and other predators that nest along the forest edge. These brood parasites lay their own eggs in the songbirds' nests, often ejecting the native eggs. Songbird chicks hatched in such nests regularly die since the cowbird chicks are larger and more aggressive. The songbird parents are left to raise these intruders as their own.

Christopher Sauer
West Bend

My immediate reaction when seeing the topic of your piece was "Oh no! Another cat-hater writes an anti-cat article." However, after reading it, my opinion changed. I am relieved and grateful for an unbiased well-written informative piece that states facts as accurately as possible and provides suggestions for pet owners to be more responsible.

We have 12 friendly felines on our farm, most of which were strays that wandered in or were dumped out of passing cars. A newcomer cat is given about two weeks to become tame enough to catch and handle or it is shot or euthanized. Fortunately, we haven't had to destroy any cats for several years.

Those cats choosing to stay are immediately vaccinated and wormed. I keep a supply of 4-way cat vaccine and Strongid wormer in my refrigerator. Then an appointment is made with the vet clinic for rabies vaccines and spaying or neutering.

Probably due to the neutering, our cats stick pretty close to home. They are seldom out of calling range. We don't have a problem with them killing birds because there are ample mice, Norway rats, shrews and moles. Though we are entertained by songbirds in our trees, we choose not to put up feeding stations because of the cats.

I also agree that declawing is not effective in curbing predatory behavior. I think only strictly in-house cats should be declawed as necessary. One of our tomcats, who lost a front paw, is just as deadly on the rodent population as the four-legged cats.

Healthy, vaccinated, neutered cats that are well-socialized to people are definitely a different breed from uncontrolled feral cats.

My thanks to Mr. Coleman and Professor Temple for a piece which will, I hope, educate and have a positive response from cat lovers and cat haters alike.

Pauli McGwin

Keeping cats confined helps protect both cats and wild things. In my childhood, our cats were locked in the old hen house every night.

We also enjoyed the badger photo. My wife and I were familiar with a Michigan badger that lived comfortably in a farm kitchen just outside of Ann Arbor in the 1930s. He eventually died of old age. I guess those Wolverines know how to handle the badgers!

Karl E. Goellner

We were disturbed by your "On the prowl" story, which singles out the common house cat as the number one predator of songbirds and small animals in the United States. We feel it is irresponsible to attach astronomical "kill" figures ranging in the millions based on a limited study of 60 radio-collared cats by two people.

The article flies in the face of a report from the June 1996 issue of Tufts University of Veterinary Medicine's CATNIP newsletter. It was based on numerous surveys and field studies across the United States. It states clearly "Most studies show that as a general rule cats do not pose a threat to population numbers of their prey." This is true because prey animals have adapted to predation over millions of years. It also states that birds rank far behind small animals as prey because they are more difficult to catch.

The only exception appears to be when cats are introduced to ocean islands where the birds have not evolved strategies to protect themselves. One study even shows that cats alone could not rid a barn infested with rats and mice. The rats were quite capable of defending themselves.

I suggest your writers broaden their studies before writing such a misinformed, sensational article.

Bill and Helen Carson

The UW researchers did not base their work on one study, nor did they state that cats are the number one songbird predator, nor did they state that birds make up the largest percentage of the free-ranging cat's diet. They were careful to state that small mammals constitute at least 70 percent of the rural cat's diet. They also carefully explained possible variables and provided a range of figures in estimating bird predation by feral cats. No one has determined that cats are the sole cause of declining bird populations, but they are certainly a factor – along with habitat destruction, chemical usage, development, and parasitism.

We take a different attitude. We love our songbirds at the feeders and feed the wild cats in our area with lead. Goshawks take enough of the birds without someone's cats creeping around our property. As for mice, our black lab does a fine job cleaning them up.

Ann and Mike Zelinski

Thanks for the excellent article on depredation of songbirds by free-roaming cats. We can only reiterate your suggestions that cats be kept indoors whenever possible for the safety of both cats and neighboring wildlife. We also support spaying and neutering.

We disagree, however, with the suggestion to declaw cats as that surgery amputates the last joint of each toe, not just the nail. Cats use their claws for self-defense, climbing and balance. There were better and more humane suggestions listed in your article, in our opinion.

Mike Markarian
The Fund For Animals
New York, NY

Free-ranging, feral cats also take a toll on small game. I've observed cats chasing young rabbits and squirrels in the park across from home. I think it's time to consider if feral cats should be considered predators that could be legally removed from the ecosystem to limit the damage to game and nongame species alike.

Ron Stresing
South Milwaukee

Like Moths to a Flames

I saw a recent clip in the newspaper stating that a university researcher who experimented with gypsy moth sex pheromones 20 years ago still attracts male gypsy moths when he travels outdoors during their mating season. Perhaps we can rub this scent on birds and bats that eat gypsy moths and the moths will be attracted to the predators that eat them. Wouldn't that be an interesting solution to the gypsy moth problem?

R.G. Kortsch

Silver, Not Sugar Maple

I grew up in Kewaunee and several HUGE silver maples (Acer saccharinum) grew on our neighbor's property across the road from our home. Every fall most of their leaves landed on our front lawn where my brother and I had to rake them. How well I recognized your nice photo of a silver maple in fall color!

It's not the sugar maple (Acer saccharum), our state tree. We have hundreds of them where we live now in central Door County – now I know THEM well!

Roy Lukes
Egg Harbor

I've been an avid reader of your publication for at least 25 years. The contents and pictures are informative to all readers, particularly young people who see the magazine in schools. Because the magazine is a learning tool to many, I want to point out that the "sugar maple" pictured on p.15 is actually a photo of a silver maple. Most of the time the sugar maple's fall colors are red or orange, not yellow. The most identifying characteristic is the leaf's shape, which is far more pointed than the sugar maple shape shown on the Canadian flag. One mistake in 25 years is a better record than I have.

Doug Laundrie, Jr.
Green Bay

Five things tell me the maple you pictured was a silver maple, not a sugar maple: 1. Sugar maples never turn a uniform color; 2. Their leaves don't have sharp fingers; 3. Their leaves don't curl up on the ground; 4. The pale, yellow leaf color is not as bright or brilliant as the sugar maple produces; and 5. The branch structure is weak-limbed, not like the sturdier sugar maple.

By the by, I do enjoy the magazine and send it on to the unfortunates who live in other places.

Jerry Gallagher
Green Bay

Thanks also to John Winkowski, Bessemer, Mich.; Josh Sulman, Madison; Gary R. Fox, Delavan; Charles A. Carpenter, Madison; and Dr. James E. Youker, Milwaukee, for commenting on this mistake.

Ecosystem Management

Your magazine promises the impossible by defining ecosystem management as "a means to pursue human convenience without causing major (ecosystem) disruption elsewhere." Using the term "human convenience" perpetuates the belief that nature is ours to use and control. Modern human activity is exotic in natural ecosystems. The problem is not how to maintain current levels of resource exploitation while maintaining ecosystem integrity, the problem is how to control human population growth and constrain resource consumption.

What assumptions must be met to make ecosystem management work? Are they realistic? In referring to degradation of water quality in Fox Lake, you state that "if the disturbances are caused by human actions, the community must adjust its working relationship to the lake..." The reality is, we've known for decades what the problems were at Fox Lake and how to treat them. For years management agencies, including the Wisconsin Department of Natural Resources, have treated the symptoms for lack of the political might to challenge the agricultural industry.

Given the historical inability of social and political mechanisms to protect ecosystems, why should we expect anything different by introducing a new "buzz word?" Humanity must begin to view itself as part of nature rather than master of nature.

John M. Woodcock

Lots 'O Nest Boxes

Thanks for publicizing nest boxes offered by the Beaver Dam Senior Citizen Center. We now offer cavity-nesting houses for bluebirds, tree swallows, purple martins, wrens, wood ducks, owls, kestrels, squirrels, robins and house finches. We also make rabbit and sparrow traps and all-cedar butterfly houses. Now we are branching out into PVC plastic bluebird houses, which seem to thwart English sparrows and raccoons. Contact us at the center, 114 E. Third Street, Beaver Dam, WI 53916.

Don Kopff
Beaver Dam

Bluebird Blues

I have several bluebird houses, but the birds have little luck fledging their young. The birds that hatch die when they are about three-quarters grown. Then I notice brown ants about the bottom of the nest. I had heard of using detergent to repel ants, so I wiped a small amount of anti-bacterial soap on the inside bottom of the box and eliminated the ant problem. Thereafter the birds fledged their young.

Could this explain population declines in other birds, especially ground nesters?

Lewis A. Gade

We asked UW-Extension Wildlife Ecologist Scott Craven your question. He said the ants were more likely just the clean-up crew after the birds had died. Craven recommends asking a community librarian to help you find literature from Bluebird Restoration of Wisconsin, Inc., which studied whether insects damage nesting bluebirds.

Bird Feeding Tip

I have a bird feeder with a plastic container which holds the seeds. I find that the plastic weathers and loses its clarity. Treating the surface with a polish like Armor AllŪ protects the plastic and renews its clarity. I treat the plastic every time I clean and fill the feeder. It works great and does not seem to harm the birds.

Joan C. Hoffman

Where's the Book?

I sure want to get a copy of the book you mentioned in the December Wisconsin Traveler column, A Seasonal Guide to the Natural Year for Wisconsin, Michigan and Minnesota, by John Bates. Where can I locate it?

Diane Christianson
Elko, Minn.

The publisher, Fulcrum Publishing in Boulder, Colorado, delayed publication until April 1997. It should be available soon at local bookstores.

Weather Wonderer Reallly!

How can you state matter-of-factly that during the past Ice Age the world mean temperatures were only ten degrees colder than they are now? Were thermometers invented that long ago? Who kept records? Can one be that exact?

Wausau, Wis. Reader

Author Dick Kalnicky responds: As a worldwide average, it was about ten degrees colder than now. However the temperature variance was not uniform – it was much smaller at the tropics. At about 45 degrees latitude, where Wisconsin is, it was likely more than 10 degrees colder as this area was mostly covered with glaciers. However, remember our present average temperature is 43-44 degrees Fahrenheit, so even a cooling of 15 degrees would have put our average below freezing. The largest cooling during the ice ages occurred in higher-latitude continents: northern North America, Europe and northern Asia.

We can make some pretty good guesses because there is a distinct link between climate and vegetation zones. Each type of vegetation, such as boreal forest, grasslands, oak hickory forest, and so forth, grows in a specific climatic range. Through radiocarbon dating and pollen analysis of ice cores and other samples geologists and climatologists have reconstructed vegetation and climatic zones that occurred during the ice ages. These types of studies have been ongoing for at least 40 years. There is a lot of scientific evidence that appears undisputed by climate experts such as those at the University of Wisconsin-Madison Meteorology Department.