Studying Squirrels

Gray and Fox Squirrels: Identification Orange or rust backs and sides Orange bellies Black-fringed tail Gray backs and sides White or gray bellies White-fringed tail Has a black morph and albino form Some variation in colors, can be fox squirrels with primarily white bellies and gray squirrels with hint of rust on backs and sides.

Some Other Differences Gray squirrels prefer forest interior; fox squirrels like edges and sparse forest and even venture out in prairies and fields Fox squirrels can be aggressive, often facing down predators Gray squirrels are more cautious and will head for nearest tree instead of fighting Except that gray squirrels will chase off fox squirrels Fox squirrels will travel larger distances over land, even running from threat on land. Gray squirrels go immediately to nearest tree.

Some Similarities Like nuts in particular, but are opportunistic Will cache nuts, especially in fall Find nuts through sense of smell Prefer to nest in tree cavities but will also make leaf nests Have one brood in early spring and often a second midsummer Can smell nuts up to 1 foot below snow “Chases” in late winter include several males following a single female. Interesting gray squirrel fact: overpopulation would trigger migrations. In early 19th century when east covered in dense hardwood forest, observers reported migrations through the trees – from tree to tree. A major migration of thousands of squirrels occurred in October 1968 in Tennessee, Georgia and North Carolina. Attributed to nut boom in 1967 followed by early frost and lack of nuts.

Animal Behavior Ethology = the study of animal behavior and includes both what an animal does and why it does it. Ethogram = a description, usually in the form of a list, of all of an animal’s normal behaviors. Why study behavior: What an animal does and how long it spends doing it Indicate how an animal feels in its environment Indicate learned versus innate behaviors Allows for comparisons between different populations Identification of area specific patterns Does weather, season, etc influence behaviors? Does the same species in different habitats behave in the same way? Are there any learned behaviors? Does the animal’s behavior change in the presence of humans?

Some Methods for Observing Behavior Initially can be useful to create a list together, or provide students with a list of possible behaviors, with room to add more Focal animal: choose a single animal and at set intervals record what it is doing Group scans: at set intervals scan a group of individuals and record all of the behaviors observed Need to also record date, time of day, weather conditions, and anything else that might impact the data.

Exploring Squirrel Behavior Resting Grooming Eating or searching for food Hiding or watching for danger

Travelling: ground, tree, etc. Chasing Begging Caching Travelling: ground, tree, etc.

Other Squirrel Investigations One way to study squirrels and other animals is through FOOD! Exploring the foraging behavior of animals can reveal a great deal about how they perceive their environment. Can explore this by providing animals with artificial foraging trays.

Other Squirrel Investigations Squirrel food preferences: Different types of foods (e.g. sunflower seeds vs. hazelnuts vs. peanuts) Shelled versus unshelled nuts (hazelnuts work great for this) Seasonal differences in preferences Presence of alternative food sources Explore different substrates Food colors Temperature of the patch

Landscape of Fear Based on risk of predation Some areas within a habitat are safer than others. Squirrels prefer to spend their time near trees Proximity to tree allows quick escape from predators Shade of tree makes squirrel less visible

How to measure the landscape of fear? Giving Up Density (GUD) is the amount of food left behind by a forager in a food patch An indirect way to measure Predation risk can then be measured by placing food patches in areas of varying risk. If an animal feels safe, it will keep foraging until it depletes the food to the point it is no longer worthwhile to continue = less food left behind = lower GUD If an animal does not feel safe, it will spend more time looking for predators than foraging, and is more likely to leave sooner = more food left behind = higher GUD

How to measure the landscape of fear? Possible set-ups: Near tree versus far Near a road or path Near a yard with a dog Could also compare city squirrels to suburban squirrels to squirrels in more natural settings

The Landscape of Fear By replicating the food patch setup in several locations throughout a habitat, we can actually map out the landscape of fear.

Experimental Data In a given experiment, we can predict outcomes/formulate hypotheses. Data can be analyzed by taking the average GUD of each patch type.

Experiment Write-Up Can also discuss observations of things that may have affected the data, for example: Weather conditions Normal/abnormal activity in the area Different characteristics of stations (near busy street, tucked away in the woods, etc.)

Project Squirrel Website: http://www.projectsquirrel.org/ Citizen scientist project through UIC and Chicago Academy of Science led by Dr. Joel Brown and several of his graduate students Focused on gray and fox squirrels, specifically how the distribution and environments of these species differ Some of the information they collect: Kinds of trees in an observation site Any dogs or cats around In addition to being interesting animals to watch, squirrels can tell us a lot about our local environment and how it is changing. To gain this insight, we must gather data about as many individual squirrels in as many places as possible. What to do:  Take a look around your home, office, school, or anywhere you are and, whether you see squirrels or not, click on the green button above to submit your observations.  We want to know where squirrels are as well as where they aren’t. How often:  You can submit as many observations from as many places as you like.  It’s most effective to submit at least one observation per site per season but the more observations the better. Who:  Anyone of any age can participate.  Make it an office game or a classroom project, compare notes with friends in other states, get your family involved—everyone can observe nature.