Red Squirrel

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Red Squirrel
American Red Squirrel
Tamiasciurus hudsonicus
Class: Mammalia
Order: Rodentia
Family: Sciuridae

Smaller than the Gray or Black
Squirrel & larger than a chipmunk.

Less than half as large as the gray, this noisy little squirrel is Minnesota's smallest tree squirrel. It is found in every county of the state, but is most common in evergreen (conifer) forests. Red squirrels are somewhat larger than chipmunks.

Reds rarely measure much more than somewhere around twelve inches, from their noses to the tips of their tails and weigh less than a pound. During the summer months, the red squirrel's fur is actually a bit rust colored Ė it is a brownish red shade and orange-red when colder weather arrives. Its underbelly is white.

During the summer, the squirrels will have a pronounced stripe of black fur going up its sides; it typically separates the white underbelly from the rust red upper side. The tail is not as thick or bushy as other North American tree squirrels.

Red squirrels often migrate if their local food supply runs low. During these migrations they will often cross water and are good swimmers.

They are well adapted for climbing and running through the trees with compact, muscled bodies, strong claws, and powerful hind limbs. In this species, the females and the males tend to be pretty much the same size. The American Red Squirrel has been found in a black phase and recently, a white phase (not albino) in Alaska. It is noted for its bright eyes, compleate with an elegant white ring around each eye, perky disposition, and chattering, rattling call. American Red Squirrels are also referred to as Pine Squirrels, North American Red Squirrels, and Chickarees.

DIET

Red squirrels are not picky eaters. They favor pine, fir, spruce, and cedar seeds, which have a high energy content to fuel their hyperactive metabolism. Piles of discarded Pine cone cuttings can be found on stumps or rocks where a squirrel ate. In summer and fall, red squirrels cut and store thousands of green cones in hollow trees or underground caches called "middens", which they fiercely defend. In deciduous forests, they add nuts of all kinds, acorns, hickory nuts, walnuts, maple seeds, buds, berries, tree sap, spruce buds and needles, willow leaves, poplar buds, flowers, bark, shed antlers, reptiles, insects, and mushrooms, including amanita species, which are poisonous to humans, birdsí eggs and young, mice, roots, tubers, wood, bark, stems, grains & fruit.
Part of the reason red squirrels are so territorial is because they store food in their area, in a central location. Typically, a red squirrel will use a brush pile, a hollow log, or a chamber hidden underground to store their food. They are able to relocate these buried seeds 30 cm underground and 4 meters below snow with their tremendous sense of smell. Many seed stockpiles are not recovered, however, making red squirrels a key tree planter and seed disperser.

Juvenile American Red Squirrels must acquire a territory and midden prior to their first winter. Juveniles without a midden do not survive their first winter. Offspring can acquire a territory by competing for a vacant territory, creating a new territory or by receiving all or part of a territory from their mother. This somewhat rare. The prevalence of this behavior is related to the abundance of food resources and the age of the mother. In some cases females will acquire additional middens prior to reproduction, which they later bequeath to their offspring. Offspring that do not receive a midden from their mother typically settle within 150 m (3 territory diameters) from their natal territory.

These squirrels also have a bit of a sweet tooth, and sometimes tap into sugar maple trees, so that they can harvest the sugar that is located in the sap. During fall when they are gathering food, red squirrels may become covered in the gum that oozes from pine trees.


Behavior

Adapted to life in trees, these tiny acrobats demonstrate prodigious agility when running at breakneck speed from branch to branch. They are most active in early morning and late afternoon. In winter they travel in tunnels under the snow.

The red squirrel is a very solitary little creature. In fact, each red squirrel takes it upon him or herself to defend a territory that ranges in between one and three acres. Not only are they defending the territory from other species of squirrels, namely grey squirrels, they are also defending from other red squirrels. As you can thus imagine, these squirrels are considered quite aggressive, certainly more so than the rather shy gray or black squirrel. Although they are quite small in size, they are well known for taking off after the significantly larger grey squirrels, especially if they infringe on their territory.

They are, however, much like grey squirrels, because they do not hibernate during the winter months and instead remain quite active all throughout the year. However, they do not like extremely harsh and inclement weather, and so have been known to seek shelter and remain there during particularly intense storms.

Red squirrels are very vocal. Since they are intensely territorial, they will scold trespassers with chatters, screeches, whistle, chirps, rattles, growls, and foot stomping and tail flicking. They will often sound like a whining puppy when the weather is very warm. one sat in front of the feeder for two hours in the summer of 2010, on an unusually warm day, and lamented the whole time.


Nests & Reproduction

Nests are most commonly constructed of grass in the branches of spruce trees, or cavities in the trunks of spruce & poplar trees, old woodpecker holes, tree hollows, or any other small crevice, sometimes a hole in the ground. In the northern part of their range, red squirrels often spend the winter in a system of underground tunnels. Sometimes they construct them in fallen hollow logs. The tree top nests consist of a 12- to 19-inch ball-shape using leaves, twigs and bark. Nests are lined with shredded bark, grasses, and leaves. Each individual squirrel has several nests within its territory. Females with young move offspring between nests.

Males and females can breed for the first time at one year of age but some females delay breeding until two years of age or older. Most females produce only one litter, but in some years reproduction is skipped while in other years some females attempted to breed twice. In Minnesota one breeding season generally takes place around March or April.

Females enter estrus for only one day, but venture from their territory prior to ovulation and these exploratory forays may serve to advertise their upcoming estrus. On the day of estrus, females are chased by several males in an extended mating chase. Males compete with one another for the opportunity to mate with the female.

After a gestation of 31 to 40 days, the female gives birth to 1 to 8, usually 3 or 4 offspring. Males donít participate in rearing the young. The offspring are pink and hairless at birth and weigh approximately 7-10 g. or about .25 oz. They grow at approximately 1.8 g/day while nursing but do not reach adult body size until 125 days of age. Offspring first emerge from their natal nest at around 40 days of age but continue to nurse until approximately 70 days old. Seven to twelve weeks. In the fall following their birth the young disperse from their mother's home range.


Population

American Red Squirrels experience severe early mortality on the average only 25% survive to one year of age at which time the survival probability, increases, to five or six years with a maximum lifespan of eight years. The average lifespan in captivity is 10 years.

Reds fall prey to hawks, owls, fishers, bobcats, fox, martens, Lynx, coyote, wolves, weasel, and domestic cats. Predation on adult American Red Squirrels is thought to be relatively low compared to other smaller mammals living in the North, such as rabbits and chipmunks. On the other hand predation to young reds can be fairly high. Red squirrels are quick and agile and can escape predators by taking refuge in thick vegetation or in the trees. Red squirrels are also fairly aggressive small animals and will defend themselves if cornered.

Minnesota has plenty of red squirrels because there's plenty of squirrel habitat. Each year, hunters harvest thousands of red squirrels, which don't provide as much meat as the larger squirrels, but the body parts are a source of valuable material. About 1 to 3 million red squirrels are harvested annually for their fur in Canada, bringing in about one million dollars.

Red squirrels can have a large impact on tree populations in two ways. They can severely limit the regrowth of conifer trees because they eat so many of their seeds. However, through their activities they also distribute the spores of beneficial fungi that help trees to acquire nutrients and grow and they accidentally plant the seeds of young trees in their catches, improving their chances of growing. Red squirrels are a important prey animals for many small predators because of their abundance in the habitats in which they live.

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