More Animal Sign

This morning I took a short wander around the field beside the Conservation District office with hope of finding some more animal sign to photograph.  Here is what I found...

When I arrived at the office this morning I noticed a domestic cat at the edge of the parking lot.  With several nearby homes this was not much of a surprise.  

The cats are drawn to the area by the presence of small mammals (voles and rabbits) and birds in the nearby field.  I decided to follow one set of cat tracks to see where they led.  The tracks meandered all over through the field.  At one point I did see where a cat had paused to examine a tunnel going down through the snow.  Freezing rain earlier this month transformed the surface of the snow into a thick layer of ice.  This ice protects the mice and voles that us the space below (called the subnivean zone) quite secure from predators above the snow - for more info on the subnivean zone check out "Next stop, the subnivean zone!" from February 2014

Nearby I noticed a single Black-capped Chickadee preening itself in an Autumn Olive bush.  Chickadees have several winter survival strategies including bulking up with fatty foods, puffing up, and even entering a state of torpor - see "Chickadees in Winter" (January 2013) for more information.

Many of the Autumn Olive shrubs in the field have been severely damaged by rabbits (and to a lesser extent, voles) over the past few winters.  This year is no different.  Because rabbits are almost exclusively vegetarian, their food options are limited during the winter months.  One reliable food source that is available is the tender buds, bark, and small branches of trees and shrubs.  Rabbits snip off the buds and branches and strip the bark with their sharp chisel-like incisors.  If enough bark is removed the tree or shrub can potentially die.  This can be a problem for people that own orchards or have recently planted small trees.  It's not a problem when the rabbits are munching on invasive species like the Autumn Olive.

Did I find anything more exciting?  No, not really.  I did see a vole scurry under the snow near a shrub, but was unable to get a picture.  I keep checking the snow in this field hoping to find a coyote track or even a deer track, but so far I have been disappointed.  That's really okay.  I got to get outside and away from my desk for a few minutes and was able to interact with nature.  It gave me a slight recharge that I needed.

Good deer, bad deer - A Cartoon from 1960

Last week I shared a cartoon by Oscar "Ozz" Warbach from the January - February 1961 issue of Michigan Conservation.

I thought I would share another Ozz Warbach cartoon from Michigan Conservation (March-April 1960).

One of the biggest complaints that we hear in our office is about wildlife damaging crops and other plants.  At the same time, many of the programs that we work on in our office are designed to help wildlife by improving habitat.  As illustrated by Mr. Warbach, the issue was much the same 50 years ago.

Winter rabbit sign

During Winter, many small animals become very secretive.  With the leaves being gone from most plants they become extremely wary.  Some species retreat to the space beneath the snow - the area known as the "subnivean zone".  Other species become mainly nocturnal to hide from the eyes of daytime predators, but in some ways Winter makes it easier to tell that these animals have been around.

One of these animals is the Eastern Cottontail Rabbit (Sylvilagus floridanus).  While the Eastern Cottontail  is one of the most common mammals in Eastern North America, it can be difficult to see just how common they are.  They prefer brushy areas where they can hide from their many predators.  Because they browse on leafy vegetation, their feeding often goes unnoticed.  Being small and light (less than 5 pounds) they rarely leave tracks.

However, Winter exposes the lives of Cottontail Rabbits. It becomes easier to see what they are eating and where.  Without green vegetation, the diet of rabbits switches to twigs, bark, and buds.  The rabbits use their sharp incisors to strip bark from small branches and trunks.  If enough bark is removed, this has the potential of killing the plant. 

Cottontail Rabbit sign - stripped bark and clipped branches near the snow line

However, rabbits often get blamed for damage that they do not cause.  Any bark removed by a rabbit will be above the snow line (to a height of about 18 inches).  You can often tell how high the snow was during the previous winter by looking for rabbit damage.  On the other hand, damage right at ground level was probably caused by mice or voles.  When mice or voles chew on trees in the Winter it often goes unnoticed because it occurs in that subnivean zone below the snow.

Cottontail Rabbits have been feeding heavily on this clump of shrubs

In addition to removing the bark, rabbits often leave another sign of their feeding - branches that are neatly clipped off at an angle.  Deer also eat the ends of branches, but because they lack upper incisors the branches that they eat will have a torn or jagged appearance where they twisted or ripped them off.

Branches eaten by Cottontail Rabbits are neatly clipped at an angle

Another sure sign of Winter cottontails is their scat.  Rabbit droppings will appear as piles of dried, brown spheres containing shredded plant fibers.  These droppings look very much like cocoa puffs.  Because their digestive system does not do a good job of processing all the nutrients in the plants, rabbits will often eat their own droppings so the contents can be digested a second time.

Rabbit droppings - Do not eat the cocoa puffs!

A third sign of rabbits that winter makes visible is their tracks.  Snow exposes the movements of rabbits and allows us to track their paths of travels.  While Cottontail rabbits have large feet (in proportion to their body size) that allow them to travel across packed snow, they do not like moving through deep fluffy snow any more than most other mammals.  They usually will stick to well defined paths or runs of packed snow under these conditions. These runs (and individual tracks away from the runs) are easy to see and show us where the rabbits travel between food sources and cover. 

A partially drifted in rabbit run leading to an isolated shrub.

We are not the only species capable of recognizing rabbit runs.  Birds of prey also notice the paths made by rabbits and will often perch over them waiting for an unsuspecting Cottontail to make a move.  If you follow rabbit runs, sometimes you will find places where a hawk or owl stooped down to take a rabbit.  A patch of disturbed snow with wing makes, some fur, and a few spots of blood are often all that indicate a successful kill.

This well used rabbit path runs for dozens of yards in a nearly straight line between patches of cover.

A little bit of snow cover and knowledge of the signs to look for makes it easy to determine if Cottontail Rabbits are around and can help remove some of the mystery from the species' habits.

Native Species Profile - Eastern Cottontail Rabbit

The Eastern Cottontail Rabbit (Sylvilagus floridanus) is found across eastern North America from the Atlantic Coast west to the Great Plains.  It ranges north into southern Canada and New England and south to the Gulf Coast.  Its range extends south into Mexico, Central America, and northern South America.

An adult Cottontail Rabbit "periscoping" for a better view above vegetation