Small Mammals That Excite Even A Wildlife Biologist

I apologize in advance for the poor quality of the two photos in this post, but I couldn't resist including them. Within a week's time, I saw two mammal species that made even esteemed Cardno JFNew wildlife biologist Jeremy Sheets giddy.

At a mitigation wetland at a landfill in Lake County, Indiana, I was sampling vegetation quadrats when I heard a Mallard smacking its wing against the water. I've seen Killdeer on many the occasion perform the "broken wing" routine when trying to keep a predator away from a nest, but I'd never heard of a Mallard displaying this behavior. Still, that was all that I could imagine was going on. The wing smacking continued, so I eventually walked in the direction of the noise, but the Mallard didn't leave the spot. As I got closer and the smacking stopped, I saw that the back of the Mallard's neck was covered in blood. Then I saw a small, dark mammal bound and scurry away through the several inches of water. I'd witnessed a kill! I followed in the direction that I'd seen the mammal go but I couldn't find it. Reluctantly, I went back to sampling without seeing the predator. Soon after, I heard rustling of vegetaton from the location of the dead Mallard. I snuck back over and again saw the dark mammal scurry away. I decided this time to stay close to the dead Mallard and wait to see if the culprit returned. Less than a minute later, I saw the killer, shown below.


This was my second ever live encounter with a Mink (Mustela vision), but my first encounter when I wasn't in a car. They live in areas where there is water, such as borders of lakes, marshes, streams, ditches, and ponds. Mink are omnivores, but nearly all of their food consists of other animals, and their preferred prey is Common Muskrat (Ondatra zibethicus). These dark-colored weasel relatives are also known to inhabit Common Muskrat dens and usually eventually drive these slightly larger mammals away. At this site, there were numerous Muskrats two years ago, but this year I saw only abandoned dens. Because of their typically nocturnal habits, Mink are often not observed by humans. Mink are found throughout much of North America, with the exceptions of parts of northern Canada and the southwestern United States.

My second mammal encounter occurred at a mitigation site in Superior, Wisconsin, while I was meeting with representatives from the U.S. Army Corps of Engineers and the Wisconsin Department of Natural Resources. As we were talking, the Corps of Engineers biologist saw a squirrel come out from under a parked vehicle.


This was my first ever encounter with a Franklin's Ground Squirrel (Spermophilus franklinii), a rare diurnal species restricted in range to east-central Alberta, southern Saskatchewan, and southern Manitoba south to northern Kansas, northern Illinois, and northwestern Indiana. At first, we thought we may be looking at a Gray Squirrel (Sciurus carolinensis), but this individual was smaller than a Gray Squirrel and had a gray head and gray tail with a brown body, and we later saw its burrow in the loose soil of an exposed mound of dirt. Franklin's Ground Squirrels feed on a mix of plants and animals, with green clover leaves being the primary vegetation and caterpillars and ants being the primary animals. They are found in dense grassy areas, often along railroads and on roadsides.

It's Like Looking In A Mirror

In June, Lindsay and I, joined by Lindsay's parents, took a vacation to Costa Rica. This was our second visit to the rich coast, and this time our travels took us to Guanacaste on the Pacific side of the country. We are still going through photos, so more will show up here as we have time to get through them all.

On our first visit to Costa Rica back in 2007, the hatching Green Sea Turtles were the overwhelming highlight of our trip. This time, though, the primates provided some of the most memorable moments. We saw three of the four species of monkeys that Costa Rica has to offer; we did not see the smallest species, Central American Squirrel Monkey (Saimiri oerstedii), and we didn't get photographs of the largest species, Geoffroy's Spider Monkey (Ateles geoffroyi). The three species that we saw all have prehensile tails that are used as one-fingered fifth limbs, allowing them to move with swift agility through the treetops.

Nearly every day on our week-long trip, we heard the grunting and roaring of Mantled Howler Monkeys (Alouatta palliata) from our hotel room. We also saw these large platyrrhines on three or four occasions during our day trips. Our best looks were along our drive to a boat tour through Palo Verde National Park on the Tempisque River. Mantled Howler Monkeys have a geographical range from Mexico to Ecuador and live for up to 15 to 20 years.


Some sources consider Mantled Howler Monkeys the largest species of monkey in Costa Rica, at least by weight, as large males can weigh up to 22 lbs. Other sources say that this species only gets to 16 lbs., and that therefore the Geoffroy's Spider Monkey, which gets up to 18 lbs., is the largest monkey in the country. Geoffroy's Spider Monkeys are more slender than Mantled Howler Monkeys, however. Mantled Howler Monkeys are strictly vegetarians that live in groups usually ranging from four to 40 individuals. These groups have home ranges of 25 to 150 acres. The adjective "howler" in the common name of this species comes from the loud noises that are made by the males (most often at surise and sunset) to communicate with group members and define territories; these communicating sounds can be heard up to three miles away. When disturbed by people, Mantled Howler Monkeys are known to throw feces with precise accuracy.

While on our boat tour at Palo Verde National Park, we had some nice looks at White-faced Capuchins (Cebus capucinus). This species is known from Honduras to Ecuador and has a life span of more than 50 years.


White-faced Capuchins, also known as White-headed Capuchins, are middle-of-the-road in terms of size in relation to other Costa Rican monkeys, weighing approximately 8 lbs. Unlike the Mantled Howler Monkey, White-faced Capuchins are omnivores, feeding on fruit, leaves, insects, and even small mammals and other vertebrates. They live in troops that can consist of up to 40 individuals and have home ranges of 79 to 210 acres. Whereas Mantled Howler Monkeys have not been observed using tools, White-faced Capuchins, which are said to be highly intelligent, have been seen using tools to obtain food and as weapons, and they also apparently use certain plants as herbal medicines by rubbing them on their fur. White-faced Capuchins get their common name from the resemblance of their coloration to the cowls worn by Capuchin friars. If you have seen the Friends episodes where Ross has a pet monkey, this species likely looks familiar to you, as Marcel was a capuchin monkey.

Stay tuned for more photographs and commentary from Costa Rica.

You "Mink" my day!

I always knew when I entered my marriage that there would be times that I would have to "compromise" and do things that I was less than eager to do. This week I was pushed to the limit but in return made a young environmentalist's dreams come true. The day started as any other day until I received the following phone call.

Scott: Hey Lindsay, I need a favor... There is a dead animal next to your parents house that I think is a mink. I need you to go and take pictures of it so I know for sure what it is.
Lindsay: You want me to take pictures of a dead animal?
Scott: Well yeah!

Fast forward to a short time later. I have taken a few photos and called Scott with a description of our fallen friend. He confirms it is a mink. Hooray, mission accomplished.


Ring, Ring.. it's Scott again.
Scott: Hey Lindsay, I need a favor. I talked to Jeremy (Scott's co-worker who is a bat and other mammal biologist) and he wants the mink. Can you go and get it and put it in a Kroger bag?
Lindsay: You must be (enter explicit word) kidding me. You want me to go and get a dead animal from the side of the road?
Scott: Well yeah!
Lindsay: You are pushing it! How am I going to pick it up because I surely am not touching a dead animal?
Scott: Put on gloves!
Lindsay: You're crazy, it's gonna be all squishy.
Scott: Don't be a baby, just go get it.
Lindsay: I'll try to pick it up with a shovel but you owe me sooooo big!

When Scott returned home that day I had just gotten over my dry-heaving episode that went along with shoveling the mink into a large plastic storage bin. We put our friend in the car and headed out to meet up with Jeremy and his wife at a beer tasting. Upon arrival, we gave Jeremy the mink. I have never witnessed such enthusiasm (well not since Scott got his vasculum for Christmas). He immediately pulled the mink out of the bag and began checking it out. The mink appeared to have died from "natural causes" so it was in really good shape. Jeremy continued to smile from ear to ear and just kept repeating how much we made his day.

In order to capture the pure joy of the occasion we have attached a picture of Jeremy with the actual mink.

This photo totally made all of my efforts worthwhile! But Scott still owes me big time!

"Barking Dog"

Translated to Latin, "barking dog" is Canis latrans... we call the mammal represented by this name a Coyote.


At the time of European settlement in North America, Coyotes were restricted to the prairie region of the continent west of the Mississippi River. As a result of clearing forests for agriculture and corridors for roads, as well as the removal of the dominant predators Gray Wolf (Canis lupus) and Red Wolf (Canis rufus), the range of the Coyote began to expand. By the early 1900s, Coyotes were found throughout much of the western two-thirds of North America. By 1990, Coyotes had expanded their range from coast to coast.

The photo above was taken last weekend from our car at the intersection near Gary Avenue, Cline Avenue, and I-90 in Gary, Indiana. As stated above, Coyotes are benefitting from the geographical expansion of the human population, and are now showing up in the strangest of places (such as this one that was found in a Chicago sub shop). However, researchers have shown that Coyotes are becoming more nocturnal as a result of pressure from humans.

Just A Pup

We have a large barn on our property that is home to what seems to be a healthy population of bats. Several people/groups rent space from us through the winter and into the spring to store their campers and trailers. We let the bats stay for free. Recently, one of our renters picked up their trailer, which had been stored for nearly a year with a tarp over it. When the tarp was removed, it was covered in guano, as expected. To our surprise, however, there was also an immature bat (known as a pup), most likely a Big Brown Bat (Eptesicus fuscus), on the tarp.


To give an idea of scale, in the photographs above and below, I am wearing a standard leather work glove. Big Brown Bats are common and widespread in North America, as they are known from southern Canada through the United States, with the exception of south Florida and southcentral Texas. Big Brown Bats often overwinter in buildings, though some will migrate and overwinter in caves. During the summer, they roost in buildings or hollow trees. An impressive fact about the species is that they can fly up to 40 mph.


Bats are very beneficial, as they feed on insects including wasps, ants, and beetles, some of which are serious crop pests. No need to worry about this little one. Pups often fall from the roosting location; those that can climb are often retrieved by their mothers. I took this bat back into the barn and climbed a short distance up a ladder before putting the bat near a vertical beam. It immediately began climbing up towards the rafters.

Special thanks to my coworker Jeremy Sheets for providing his opinion that this likely is a Big Brown Bat.

Place Your Vote: Cute or Ugly?

One day last week, I arrived home from work to find a Virginia Opossum (Didelphis virginiana) feeding on black-oil sunflower seeds under the tree in our front yard from which we hang several bird feeders. We have since seen our new guest on several occasions munching on seeds under the feeders in our backyard, and taking shelter under the stairs behind our house.


Although the Virginia Opossum has more teeth (50) than any other Indiana mammal, members of the species are not generally aggressive. When frightened, opossums often involuntarily act like they are dead, leading to the colloquial phrase "playing 'possum;" however, they will also often hiss or growl and show off their sharp teeth. Opossums will eat nearly anything and are considered omnivorous scavengers. The species is found in Central and North America east of the Rocky Mountains, but has also been introduced along the West Coast of the United States. This is the only marsupial in North America north of the Rio Grande River. As such, newborn opossums live in their mother's pouch for one to three months before they become too large and need to migrate from the pouch to their mother's back.


This leads to my survey question... what do you think? Is the opossum cute or ugly? Personally, I think they are very cute (just look at that face!), but Lindsay disagrees. Please help us settle our debate.

Sources:
http://www.opossum.org/facts.htm
http://en.wikipedia.org/wiki/Virginia_Opossum
http://www.in.gov/dnr/fishwild/5686.htm

More Dead Animals?!?

I'm beginning to wonder about this place. In the past, I have posted about finding a Big Brown Bat, Star-nosed Mole, and Least Weasel dead on our property in northern Indiana. On March 16, 2009, we added to our mausoleum of mammals after finding these two rodents dead at different locations on our trails.

I believe that these are Meadow Voles, Microtus pennsylvanicus; I've sent them to Dr. John Whitaker at Indiana State University for a positive identification. You may be thinking... "looks like a mouse to me." Voles differ from mice in having rounder heads, smaller ears and eyes, stouter bodies, and shorter, hairy tails.

Meadow Voles are widespread in North America, found in a variety of habitats in all regions except the southwest and southcentral states. Research shows that their populations are secure, and that they actually seem to be expanding southward. Meadow Voles breed throughout the year, including in the winter if there is enough snow to act as insulation. They are active both during the day and at night. The life span of a Meadow Vole in the wild is up to a year, but is usually less.

Female Meadow Voles are said to be territorial, while the males have ranges that cover three times the area of a female. Unlike the males of other vole species (such as the Prairie Vole, Microtus ochrogaster), male Meadow Voles are promiscuous little guys. To be protected while they forage, these proficient diggers, create tunnels through vegetation and the ground beneath.

Look at those chompers! The diet of the Meadow Vole is comprised mostly of vegetation, though they have been known also to be cannibalistic. They must spend a good part of the day and night eating, as they are known to consume 60% of their body weight every day!

It is unfortunate that we continue to find these animals dead on our property, but doing so gives me a reason to learn more about the species. Even land as degraded as our old field is full of interesting creatures.

White-nose Syndrome, or Just White Fungus?

UPDATE 28 JANUARY 2010...

After personally observing the Big Brown Bat discussed in this post, Dr. John Whitaker has told me... "The material on the nose appeared to be from the hibernaculum and was a mixture of dirt and hair stuck to the nose area and peeled right off with a needle. It was not white nose." Good news.

White-nose syndrome has received a lot of press lately. This disorder, which is characterized by a white fungus forming on the muzzle of hibernating bats, is currently known to exist in the northeastern United States and west to Pennsylvania. In just the past two years, it has led to the death of over 100,000 hibernating bats (primarily Little Brown Bat, but also Indiana Bat, Eastern Pipistrelle, Northern Long-eared Bat, and Small-footed Bat). This is bad news if you don't like mosquitos; one bat can eat up to 75 percent of its own weight in flying insects during a single summer.

Photo from New York Department of Environmental Conservation, www.dec.ny.gov

On January 31, before our recent spring weather (which is about to revert back to winter, by the way), I found a dead Big Brown Bat (Eptesicus fuscus) just outside our back door. The bat was identified as a first year juvenile by Dr. John Whitaker based on my photos. While this little guy seemed pretty small when all folded up, when my coworker Rob Wolfe stretched it out to measure it, the wingspan measured a stunning 310mm! Other dimensions included: total length, 109mm; forearm, 43mm; tail, 41mm; hind foot, 10mm; and ear, 13mm, though this last measurement could have been conducted incorrectly.

Big Brown Bats can be found from southern Canada to northern South America, and into the West Indies. They can live up to 19 years, but many don't make it past their first winter because they don't store enough fat to last through hibernation. While all of our other species of bats migrate south and hibernate in warmer climates, the Big Brown Bat will spend the winter hibernating in cooler areas. They even will become active during this period of hibernation if they become too cold or if their hibernaculum is disturbed.

A variety of insects are eaten by Big Brown Bats during the spring-early fall, including dragonflies, moths, flying ants, flies, lacewing flies, and wasps. Most commonly, however, they feed on beetles.

It is possible that this bat died as a result of the cold temperature that it encountered when it left its hibernaculum. However, the white fungus on its muzzle makes me wonder if this bat could possibly have died as a result of white-nose syndrome, even though this disorder has not been observed as far west as Indiana (yet). The fungus on the bat I found looks a little different than the photos I've seen of bats that have white-nose syndrome. If anyone familiar with this disorder has thoughts on whether this is or is not white-nose syndrome, I would like to hear them.

Rare Mammals

Lindsay and I have lived here in North Liberty since Spring 2007. From the time we moved in, we have kept a yard list for birds, reptiles, amphibians, insects, mammals, etc. To date, our bird yard list is 99 species; most of those have been seen on our property, but some have been seen or heard from our property but actually occurred across the street.

Most of the mammals we've seen on our property are the common ones... White-tailed Deer, Eastern Cottontail, Muskrat, Raccoon, Eastern Fox Squirrel, Red Squirrel, Oppossum. However, on September 14, 2007, we were surprised to find a dead Least Weasel (Mustela nivalis) in our driveway (with keys for scale). The smallest of the carnivores, these stunning little mammals probably aren't as cute if you're a Meadow Vole. When it catches up to its victim, the Least Weasel will pounce on it, wrap its legs around its prey, and kill it with a swift bite to the base of the skull. And they're fast... they can run up to 6 mph! Because Indiana is at the south edge of their range, Least Weasels are on the Indiana protected species list as Special Concern. Hopefully this wasn't the only one on our property.

Then, on July 13, 2008, I found a second State Special Concern mammal on our property. This time, it was a dead Star-nosed Mole (Condylura cristata), found in our corn crib. These unique-looking mammals most often prefer moist soils, but also will live in dry meadows. Those strange tentacles on the nose serve a couple of purposes. Along with keeping soil from entering their noses while burrowing, the tentacles also are constantly moving and touching their surroundings during normal foraging activities. Star-nosed Moles feed mostly on earthworms and aquatic insects. Indiana is along the western range of this species, causing it to be considered a species of concern in the state.