Literature Review: Wolves and Dogs

by Carl Strang

Last year produced a few published studies of wolves and dogs that caught my eye. Dogs are well established as having been domesticated from wild wolves, but the timing and nature of that new relationship have been a contentious topic. Here is a recent contribution to the debate:

Thalmann, O., et al. 2013. Complete mitochondrial genomes of ancient canids suggest a European origin of domestic dogs. Science 342:871-874. This group of researchers previously had suggested that dogs first were domesticated in the Middle East, but this new study with updated methods points to a European origin 18-32,000 years ago. They included DNA from fossil wolves and dogs in their comparisons. From an interpretive article in ScienceDaily: “By comparing this ancient mitochondrial DNA with the modern mitochondrial genomes of 77 domestic dogs, 49 wolves and four coyotes, the researchers determined that the domestic dogs [of today] were genetically grouped with ancient wolves or dogs from Europe — not with wolves found anywhere else in the world or even with modern European wolves. Dogs, they concluded, derived from ancient wolves that inhabited Europe and are now extinct.” This timing and geography point to a likely domestication by hunter-gatherers rather than agriculturalists.

Wolf at Wolf Park in Indiana

Wolf at Wolf Park in Indiana

Once the ancestors of dogs had become genetically isolated from wolves, the two populations were exposed to different selective pressures. The wolves continued to be subject to natural selection, while the dogs were influenced by human-directed selective breeding, and by the different selective pressures of living in human communities. The next study compared the development of dogs and wolves, and discovered some consequences of that divergence.

Kathryn Lord. A Comparison of the Sensory Development of Wolves (Canis lupus lupus) and Dogs (Canis lupus familiaris). Ethology, 2013; 119 (2): 110 DOI: 10.1111/eth.12044 From a ScienceDaily article. She looked at the relationship between the timing of sensory maturation and exploration behavior in wolf and dog puppies. Both acquire smell, hearing and vision in that order, at 2, 4 and 6 weeks of age. Wolves, however, begin exploration and socialization at 2 weeks, dogs at 4 weeks, and so dogs are socializing after they have the ability to perceive their social surroundings more completely. Wolves are getting fearful shocks during this period as new sensory capabilities appear, and so need an earlier and more complete contact with their social community, and never form the same kind of solid bond that dogs do.

Dogs have diverged from their wolf ancestors

Dogs have diverged from their wolf ancestors

A final, sadder note was a news article in Science magazine that explained how Isle Royale’s long-studied wolves are close to dying out.

Wolf tracks on an Isle Royale beach. Are these about to disappear?

Wolf tracks on an Isle Royale beach. Are these about to disappear?

Mlot, Christine. 2013. Are Isle Royale’s wolves chasing extinction? Science 340:919-921. Last year, for the first time in 40 years, there were no wolf pups on the island. The 2013 January count turned up only 8 closely related adults. Rolf Peterson, principal wolf biologist at Isle Royale for many years, thinks they now will die out, with inbreeding the root cause. Moose have increased as their principal predators have declined. The Park Service is considering whether to introduce new wolves to rescue the population (Isle Royale is a national park in northern Lake Superior).

Osprey Species Dossier

by Carl Strang

This dossier centers on a couple days from my kayak circumnavigation of Isle Royale, when weather compelled a 2-day stay at Hay Bay. It proved to be a highlight of the trip, and I learned most of what I know from experience of moose and ospreys during that stop. Otherwise, my knowledge of ospreys consists of limited snapshots of observations.




I saw ospreys regularly over the Tippecanoe River, in Indiana, in summer in my childhood and early teens, but then they declined. By 1970, ospreys had become rare enough that a sighting in fall at Hawk Lake was remarkable. Then we saw some at Assateague Island, Virginia, occasionally carrying a large fish in their talons or catching one from the water’s surface. They had large nests of sticks there and on buoys in the Eastern Shore area of Maryland.

Osprey nest on buoy, Chesapeake Bay

Osprey nest on buoy, Chesapeake Bay

4SE88. Osprey flying south along the Fox River between North Aurora and Batavia, Illinois, at Red Oak Nature Center.

18AU96. Hay Bay, Isle Royale National Park. At around 12:30 an osprey appeared, coursing over the bay at 30-50 feet of altitude. After about 5 minutes it dove from more than 30 feet and plunged into the water, catching a good-sized, silvery looking fish (appeared to be about as long as the bird’s wing width). With much effort the bird flew up to the ridgetop across the bay. Between 3 and 3:30, two ospreys hunted over the bay, one started a dive but aborted, one after the other drifted over toward the bay entrance. They returned around 4:00, one perching on a tree and calling with loud, high-pitched chirps. The other aborted several dives and completed one in the 10 minutes I watched, but caught nothing. By 5:00, water had greatly calmed in Hay Bay. An osprey with a fish landed in trees back from shore, opposite me. A few minutes later one flew over the bay while another called. At 5:30 an osprey flew over camp with a fish. By then it was clear that there were 3 individuals, one possible youngster calling while the other two hunted. One successful catch, a larger fish, was carried out of view. Those plunges are dramatic, the birds highly specialized. Try to talk politics with an osprey, it’ll just say, “What’s that got to do with catching fish with your feet?”

After catching a fish, the osprey turns it around head first for easier handling in flight.

After catching a fish, the osprey turns it around head first for easier handling in flight.

19AU96. Hay Bay. Ospreys were hunting by 7:30 a.m. Their ker-plooshing plunges are audible at some distance. I saw an osprey catch a good-sized fish. “Kibitzing” calls increased from a bird on shore, but then it flew out and I saw that it had a fish, too. Both flew toward the ridge across the bay, but carried their fish up and over it. Around 11 a.m. an osprey hunted the bay for a good 20 minutes, with few dive attempts. It hovered in place 2-3 seconds a couple of times. On the third complete plunge, it caught a fish and flew with it in the same direction that the two went earlier. Much calling by another, perched bird during the first half of that hunt. 2:00 decisions, decisions: do I watch the moose feeding or the osprey hunting? The osprey dove close enough to me that I could see how it holds its feet up by its head. A miss. They always shake water off in mid-air, a few wing beats after clearing the surface. 3:00 There are at least 4 osprey, all at the bay now. 5:00 An osprey caught a good-sized fish (half its length), and carried it in the same direction, followed by another, fishless bird. Ripples only, still, in the bay.

16AP00. Willowbrook. An osprey flew over, SW to NE, with a fish in its talons possibly caught in one of the ponds at the College of DuPage campus.

19AP01. Willowbrook. An osprey flew over with a large goldfish in its talons. I’m not sure what direction it was coming from, possibly north.

2009. Tri-County (JPP) State Park. Ospreys nested atop the very high utility pole at the boundary of this park and Pratts Wayne Woods Forest Preserve.

Osprey nest, James Pate Philip State Park

Osprey nest, James Pate Philip State Park

2009-12. In most springs an osprey has spent some time (most of a week at times) at Mayslake, perching on trees at the edges of the lakes and occasionally fishing.

Lessons from Travels: Isle Royale Spring Peepers

by Carl Strang

One of my favorite adventures was a solo sea kayak circumnavigation of Isle Royale in 1996. Islands have relatively few species, and this helped me to solve a puzzle that had bothered me for several years. I had been hearing a strange animal sound in late summers into autumns, a high-pitched intermittent call that sounded vaguely cricket- or frog-like. I hadn’t heard it in DuPage County, but in a variety of locations in the eastern U.S. I patiently had stalked these mystery animals several times without success. Then I found I was hearing the calls on Isle Royale. I also was seeing numbers of spring peepers.

Spring peeper on Isle Royale. The bunchberry is an indicator of the northern Lake Superior location.

Spring peeper on Isle Royale. The bunchberry is an indicator of the northern Lake Superior location.

Finally my brain made a testable connection. I knew a couple peeper locations in DuPage, and realized I had not gone into them late in the season. When I went there after returning from Isle Royale I heard the sounds. So that was the source of the sound, but I still have not figured out nor have I found an enlightening reference, which would explain why a spring peeper would peep in the autumn.

Beaver Species Dossier

by Carl Strang

The species dossier idea came from my realization in the 1980’s that much of what I “knew” about wildlife came from the scientific and popular literature rather than personal experience. I went species by species, writing what I could remember about each one from memories of my own observations. Then I built the dossiers with added notes. The dossier begins with the initial paragraphs, followed by notes dated by a code that uses two-letter combinations to signify months.


Beaver, Salt Creek at Fullersburg Woods

This aquatic rodent lives in ditches, rivers, and lakes. Observations to date have been in the Culver, Indiana, area (Maxinkuckee, Tippecanoe, Yellow River, Fish Hatchery), southern Ontario, and DuPage County, Illinois. The signs are seen much more often than the animals themselves; they are crepuscular/nocturnal for the most part, although the Canadian ones occasionally appeared in daytime, and I have seen them during the day in northern Lake Michigan and the West Branch of the DuPage River (mid-winter). Alarm signal: dives noisily, augmenting the splash with its flat tail.

Stand-alone lodge, Canada

They feed on bark and twigs of willow and other woody plants, storing large underwater piles of branches in fall for winter use. They also stripped bark from the 1-4″ diameter X 1-3′ long sticks used in building dams and lodges. The den can be in a bank or in a stand-alone built lodge. Bank dens are used in larger, deeper rivers and lakes, although built lodges also can be seen in such places. I have seen built lodges in Canada, Lake Maxinkuckee (Venetian Village), DuPage Co. (e.g., Churchill F.P.), Isle Royale. They have a distinctive appearance because of the white sticks, though some lodges on riverbanks are not rounded and so at first glance resemble piles of drift from the last flood. Mud also is used in construction. Lodges have been 8-15′ in diameter, 2-4′ high, usually on a bank.

Beaver dam, Tri-County State Park

Small streams may be dammed to create a pool (the most ambitious dam I’ve seen was on the West Branch of the DuPage River at Blackwell in mid-winter). Dams, like lodge coverings, are built of stripped sticks, mud, vegetation, usually have a slight U-shaped bend pointing downstream, and are not particularly high above the contained water level, though some on Isle Royale were taller than me on the downstream side. Very long dams can have a more sinuous shape; I’ve seen them more than 50′ long.

High beaver dam with trail, Canada

Beavers will carry branches from other bodies of water to the home pool. Cut trees are distinctive with large tooth marks and pointed (cone-shaped) ends. Beaver tracks are large, and have the rodent formula (4 toes front, 5 back), the webs of the hind feet not always making noticeable marks.

Beaver front footprint

31AU86. Beavers at Culver’s fish hatchery have reinforced the base of their dam with a heavy plastering of marl.

18DE86. Month-old beaver sign, Willowbrook Back 40: several black cherry trees had their bark chewed off on the stream side of the trunk. No others in the vicinity (willow, box elder) were damaged.

11JA87. At the mouth of Sawmill Creek, Waterfall Glen F.P., beavers this morning fed on bark of a box elder 7″ dbh, they had cut down earlier. They had made a trenchlike single path in 6″ snow between stream and trunk.

8MR87. 2 ash trees 8″dbh cut down but only some bark removed from trunk. Otherwise untouched, for months.

Beaver-felled tree, Fullersburg

28MR87. Beavers at Waterfall Glen cut three 8″ dbh bur oaks, ate much of the bark from 2 of them, in an area with much willow.

23JA88. McDowell F.P. Beavers built a long winding dam on Ferry Creek, 20-30 yards long

15MR90. McDowell. Beavers were active in the evening dark during my night hike program. We heard one chewing: identical to the sound of a squirrel gnawing a nut, and as rapid, but much louder. Several of us shined lights on it. It was on the opposite side of the river, standing up on its hind feet, against the tree. After at least 30 seconds of being illuminated, it abruptly ran into the river. It swam for another 20-30 seconds, still in lights, then walked up the bank back to the same tree, and resumed gnawing. The alarm splash is like a big rock being thrown in. I didn’t detect a tail slapping component.

13NO99. A beaver dam has been built across the very low West Branch of the DuPage River, Elsen’s Hill at the eastern horse ford.

29MR00. While running past the borrow pit at McDowell Grove Forest Preserve, I frightened a beaver into the water. It swam under the surface for 20 feet or so, a stream of bubbles revealing its position, then surfaced. Immediately it dove again, but as it did so I saw it deliberately lift its tail and slap it on the water. I could detect the sound of it, but the splash made by the posterior part of the body (spread feet?) was the louder sound. Perhaps the double sound makes it a communication for beavers, to distinguish it from other splashes.

11MR01. A beaver lodge is on the shore of the old gravel pit on Timber Ridge Forest Preserve (at the intersection of County Farm and Geneva Roads). There has been much recent gnawing of nearby woody plants.

8AP01. At around 8:30 a.m. at Red Oak Nature Center I heard a gnawing sound down near the edge of the Fox River. It was a beaver, sitting in the shallow water and feeding on the twigs of a shrub or small tree overhanging the river (intervening brush too thick to get an ID of the plant). The beaver was reaching up, biting off a branch, then consuming the twig. Less than about 3/16″ in diameter, the twig was consumed by the beaver holding it like a piece of stick candy and nibbling on it with gnawing sounds reminiscent of a squirrel working on a nut but more rapid. After 2-3 seconds of biting off the end, the beaver chewed with its molars for a few seconds, swallowed, then worked on the end some more. When the diameter of the remaining twig became greater, approaching 1/4″, the beaver turned it sideways (always holding it in the front feet) and quickly stripped off the bark.

22OC01. Beavers have been very busy in recent days at the marsh beside South Blackwell’s Heron Trail (marsh full of water thanks to heavy rains in recent weeks). They have trampled a path through the cattails all the way to Heron Trail, and have been cutting the small willows and cottonwoods into pieces, eating the bark from some of the bigger chunks, and hauling the tops into the water (drag marks visible in the mud).

6JL07. Fullersburg. A beaver swimming up the main channel along Sycamore Peninsula went to the shore at 8:30 a.m. and ate some root bark and twig bark from American elms. It continued upstream past the Visitor Center.

Literature Review: Isle Royale Update

by Carl Strang

As I mentioned in yesterday’s post, there were plenty of wolves and moose on Isle Royale when I visited there in 1996. That is one of the better monitored ecological systems, and I was interested in an update based on the 2011 winter count, as reported in ScienceDaily.

View from a fire tower on the central ridge of Isle Royale.

The year after my trip there, a new male wolf immigrated to the island from the Canadian mainland. For a time the wolves benefited from this boost in genetic diversity, but that influence has begun to decline with a resumption of inbreeding, and the island’s wolves are down to a single pack of 16 individuals.

At the same time, reduced moose numbers have allowed a rebound of vegetation and they are on the verge of an increase. One of the side benefits of travel is a personal connection that lends interest to such stories.

Lessons from Travels: Isle Royale Moose and Wolves

by Carl Strang

My short list of greatest adventures always will include my circumnavigation of Isle Royale by sea kayak in the second half of August, 1996. Isle Royale is the big island in northern Lake Superior that, to me, looks like the eye in the lake’s wolf’s head shape. The paddle around it is a 100-mile journey. I got there by ferry from Houghton, Michigan.

There was plenty of room in the hold for kayaks and camping equipment.

On the way out I had a happy encounter with Rolf Peterson, a fellow graduate of Purdue’s wildlife program, who took over the Isle Royale wolf-moose study from his mentor, Durward Allen. It turned out I was able to help. With my kayak I could reach a few moose carcasses Rolf had spotted from the air during the winter surveys but which were in remote places. There were some data and samples that needed to be collected on the ground.

I never had seen a moose, and Isle Royale is one of the best places in the U.S. to find them. I encountered around a dozen during this trip.

This fellow walked right through camp one morning.

Isle Royale is better known as a backpacking destination, but I’m really glad I did it by sea.

This is the kind of trail the backpackers must negotiate in places. I felt a mixture of respect and pity as I watched them staggering into camp at the end of the day, when I had done my relatively easy paddling in the morning and could explore the trails with a light day pack.

A sea kayak can carry everything one needs for a two-week trip. A micro-filtering pump allows one to strain the lake water for drinking and cooking.

I still have this tent, though it got a tear during a storm on a later sea kayak expedition. Shortly after taking this photo I lost the camera remote I was holding in my left hand.

Along the way I saw occasional moose skeletons previously inventoried by Rolf and his students.

Wolves and weather have scattered some of the bones.

In the southwest quarter of the island there are no established camps, so I set up on the beach that night. There I saw my first wolf sign.

The tracks were very fresh, but I knew my chances were slim of seeing one of these shy canids.

This was a very remote location, with only the occasional calls of golden-crowned kinglets to break the August silence. The following photo, which I took just before pushing off the next day, conveys some of the eerie mood of the place.

I liked to make an early start, so as to have as much of the afternoon as possible for day hiking.

The following camp at Huginnin Cove, on the north shore just east of Isle Royale’s tip, provided the next clue to the presence of wolves.

Stinkin’ fresh wolf scats on the trail near the campground.

There is a long stretch of the north shore which provides no good landing for a sea kayak.

Here you can see why.

Nevertheless, one of Rolf’s moose was there, just inland from a little break in the shoreline. I found the spot, wedged Water Strider (my kayak) between a boulder and the cliff, and climbed up carrying my tow line/anchor rope.

The little waves gave Water Strider some scratches from the rocks which she bears to this day.

After some searching I found the carcass, a female, and I bagged the smelly sample for transport to Rolf. I dubbed her Miss Moosie, and she was my companion for the remainder of the trip.

Moose were part of the northeast Illinois fauna in the wake of the last continental glacier, and wolves still were here in historical times. It was a pleasure to share a landscape with them for a while, and to imagine the days when such creatures left tracks and deposited scats on trails now occupied by Ogden Avenue and Army Trail Road.

Spring Peeper Mystery

by Carl Strang

The spring peeper is a tiny tree frog with which I have something of a history, despite its rarity in DuPage County. Where it is abundant, its high-pitched notes are a welcome introduction to the spring symphony. Research has shown that the male frogs sing in trios, collectively attracting females with which the dominant male gets first mating opportunity. They require unpolluted waters for tadpole development, and so in DuPage County occur in only a few tiny watersheds isolated from road salt, fertilizers and pesticides.

I had a mystery to solve some years back, and it took me a while to connect it with this amphibian. In the late summer and fall I heard occasional squeaky animal sounds, usually in woodlands, but I was frustrated in my efforts to locate the singers. They seldom sang, in the first place, and were quick to shut up whenever I came close, however carefully I stalked. Sometimes these high-pitched notes were single, sometimes in series of 3-4. I heard them in Pennsylvania where I lived for 5 years, in Maryland when visiting my brother, in the woods around my original hometown of Culver, Indiana, and various other locations, though not in DuPage County. These sounds were insect-like in time pattern, but had the quality of voices.

The breakthrough came in late summer 1996, when I made my sea kayak circumnavigation of Isle Royale in northern Lake Superior. There they were again, those mystery sounds, and the singers, whatever they were, seemed to be ubiquitous. My advantage there was that the species list for Isle Royale is shorter than in any other place where I had heard the sound. I was seeing lots of spring peepers, and though I continued to be unsuccessful in observing the sound being produced, I now had a primary suspect.

Spring Peeper and Bunchberry, Isle Royale

Though I never had encountered spring peepers in DuPage, and never had heard the sound there, I knew of a couple of places where they were known to occur. This made a test of my hypothesis possible after I returned from the trip. There still was plenty of early fall weather in which to seek the sound in those remote DuPage locations, and so I went to one of them. If I heard the sound there, I would consider the mystery solved. As it happened, I was indeed delighted to hear the sound produced by a few scattered individuals. But was the mystery solved completely? After all, these are spring peepers. Why peep in the fall? Also, the sound is a little different from the frog’s spring song, being squeakier, less forceful, less continuous, perhaps a little lower in pitch. Furthermore, the singers clearly are singles rather than trios. I have checked the literature, and communicated with a few frog biologists, but so far have found no sensible explanation for this behavior.

African Bird

by Carl Strang


I’m not a huge TV watcher, but “Survivor” is one of my guilty pleasures. The current series, taking place in Africa, occasionally shows a passing shot of a species of bird I have seen a number of times despite never having visited that continent. It’s also a species which nests in northeast Illinois. I’m talking about the osprey.


Osprey nest, Maryland Eastern Shore

Osprey nest, Maryland Eastern Shore



Ospreys occur all around the world. I saw them in Australia. Though there are no recent known nests in DuPage County, for the past two seasons there has been one a stone’s throw from the county’s northwest corner. I should say “baseball’s throw,” because this nest is built on one of the light poles in a complex of ball diamonds. It’s tempting to say the birds must be baseball fans.


For one species (and there is only one) to have become so cosmopolitan is testimony to the success of its complex of adaptations. Freshwater fish that stay close enough to the surface to be susceptible to a plunge-and-grasp are found on all the warm continents. Ospreys’ feet are wonders. The long curved talons are supplemented by hard sharp protruding scales on the undersides of the toes that grip the slippery prey.


Osprey carries fish head forward

Osprey carries fish head forward



My best opportunity to watch ospreys in action came during my sea kayak circumnavigation of Isle Royale a few years ago. I camped a couple days at a site called Hay Bay, which is accessible only by boat or bushwacking. There I had an excellent opportunity to watch ospreys, cormorants and gulls as they hunted for the abundant lake herring. The ospreys plummeted from spectacular heights, and when it was calm I could hear their collisions with the water from most of a mile away. Often they rose with fish that were at least a third of their own length.


Recent nesting success of ospreys in northeast Illinois bodes well for their return as a more familiar part of our fauna.

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