An online resource based on the award-winning nature guide

Posts tagged “Ursus americanus

Why You Don’t Feed Birds In The Summer (if you live in bear country)

Unfortunately, habituated bears often have very short lives.  They lose their fear of humans, become “nuisance bears” and often end up being killed.  Do not worry about the birds that have been visiting your feeder all winter.  Your bringing your feeder in will not negatively affect them, as they get the majority of their food from natural sources.  Also, when birds are nesting many feed their young insects and aren’t frequent visitors to feeders. Feeding enables humans to get a close view of their winged neighbors, but it is not necessary for the birds’ welfare.

Naturally Curious is supported by donations. If you choose to contribute, you may go to http://www.naturallycuriouswithmaryholland.wordpress.com  and click on the yellow “donate” button.


An Ingenious Recycler

Recycling is the process of converting waste materials into new materials and objects.  In the natural world, agents such as fungi and bacteria that turn dead plant and animal matter into air, water and nutrients come to mind.  If you broaden the definition of recycling to include the re-use of material, however, many more organisms come into play.

Some humans continue to feed birds in the spring after Black Bears have emerged from their dens.  The bears have not eaten for four or five months and once their digestive system adjusts, they are extremely hungry.  Available bird feeders are often raided by hungry bears at this time of year, and end up discarded on the forest floor with the seeds they contained ending up inside the bears’ stomachs.  Eventually the bears defecate and their feces contain little else but the husks of sunflower seeds interspersed with intact seeds.  Keen-eyed Black-capped Chickadees are very quick to take advantage of these recycled sources of protein.  (Check the Chickadee’s beak closely.)

Naturally Curious is supported by donations. If you choose to contribute, you may go to http://www.naturallycuriouswithmaryholland.wordpress.com and click on the yellow “donate” button.


Black Bears Active

Bears are emerging from hibernation a bit earlier than usual this year in Russia, Finland and the U.S. due to warmer temperatures.  The emergence of Black Bears from hibernation in the Northeast usually takes place next month, but they have already been active for several weeks, even in northern New England.

There is little food available to bears in April, but in March the situation is even more dire.  Therefore, bird feeders and human garbage are like bear magnets, so bring in your feeders and make your garbage inaccessible! The climate crisis is having a detrimental effect on wildlife — hibernation, migration and breeding cycles are intimately connected to the availability of food — and as a result of this out-of-sync timing, there will inevitably be more conflict between bears and humans.  (Photo: Black Bear scat filled with sunflower seeds from a bird feeder.  Thanks to Clyde Jenne and Bruce Locke for photo op.)

Naturally Curious is supported by donations. If you choose to contribute, you may go to http://www.naturallycuriouswithmaryholland.wordpress.com  and click on the yellow “donate” button.


Time To Take Down Bird Feeders !

3-25-19 black bears 1214Black Bears have just started to emerge from hibernation in northern New England, and their appetite is fierce. Male black bears will typically drop between 15 and 30 percent of their body weight, while reproductive sows can lose up to 40 percent of their weight over the winter. Although omnivores, a black bear’s diet consists of 85 percent plant material, especially in the spring and summer. At this time of year bears favor the tender emerging shoots of sedge and grasses, willow catkins, leaf buds and skunk cabbage. However, these plants are not always available to them when they first become active. Being opportunists, if bears can’t find natural food sources, they go looking for alternatives, such as those provided by humans.

Sunflower seeds are a Black Bear’s dream come true, nutritionally speaking. A bird feeder full of them replaces hours of foraging in the wild. With an outstanding sense of smell (many times greater than a bloodhound’s), Black Bears will find and raid feeders at this time of year when there is a lack of other food sources. Therefore, if you wish to avoid creating a “nuisance” bear, it is advisable to take down your feeders by April 1st. Black Bears have excellent memories, particularly regarding food sources. They will return time after time, and may resort to unwanted (by humans) behavior in order to get more of the food that was at one time available. Once this occurs, their well-being is jeopardized.

Naturally Curious is supported by donations. If you choose to contribute, you may go to http://www.naturallycuriouswithmaryholland.wordpress.com and click on the yellow “donate” button.


Fermenting Apples & Black Bears ≠ Inebriation

11-5-18 bear scat MH_20091011_233455_4If you investigate the contents of Black Bear scat this time of year, you may well find nothing but chunks of digested and semi-digested apple (pictured).  For several weeks before hibernation begins bears spend their days and nights foraging for food that will sustain them through the coming months (“hyperphagia”).  Fermenting apples lying on the ground are accessible and very popular with bears; hence, many scats contain them.

There have been anecdotal reports over the years of Black Bears stumbling around as if inebriated, and it is often assumed that this behavior is the result of their having consumed fermenting fruit, such as apples.  Waxwings, robins and other species of birds are known to get drunk (and even die) from fermented crab apples, mountain ash and blackberries, but it’s highly unlikely that bears follow suit.

For one thing, the pH of a bear’s stomach is around 3.5 – slightly more acidic than yeast can tolerate. In addition, the time it takes for a Black Bear to digest food is typically far less time than yeast would need to convert sugar into alcohol. Lastly, size would play a large role in an animal’s ability to become intoxicated. It would take hundreds of apples consumed at their peak level of fermentation to make even a small, young Black Bear even slightly tipsy.

If you see a Black Bear stumbling and acting strange it may well be because it is sleepy or perhaps sick, but probably not drunk. However, until researchers test the blood alcohol level of a bear that’s exhibited this behavior, no–one can say for sure what caused it.

Naturally Curious is supported by donations. If you choose to contribute, you may go to https://naturallycuriouswithmaryholland.wordpress.com and click on the yellow “donate” button.


A Rare Privilege

4-6-18 four black bears 636-RecoveredThe hours I spent with this ursine family were some of the most special hours of my life.  It’s possible, and probably likely, that because they lived relatively close to human habitation, they were cognizant of the fact that I meant them no harm.  Regardless, they allowed me to observe their natural behavior, and that is a priceless gift to anyone, particularly a naturalist.

Black Bears are not  the monsters Goldilocks would have you believe. Offensive attacks are very rare — aggressive displays are much more an expression of their fear than anything else.  Chattering of jaws, false charges and the like are just that — bravado. Even when it comes to defending their young, they are very reluctant to be aggressive — that is much more likely with Grizzly Bears, which are not found in the Northeast. If not encouraged to become a nuisance by the presence and easy access of human lures such as garbage and bird seed, Black Bears can coexist with humans with little to no conflict.

If you’ve enjoyed the photographs of this family of bears, you (or your very young friends) might enjoy my recently-released children’s book, Yodel the Yearling, in which many of these photos plus others appear .

Naturally Curious is supported by donations. If you choose to contribute, you may go to https://naturallycuriouswithmaryholland.wordpress.com and click on the yellow “donate” button.

 


Black Bear Yearlings Still Nursing

4-6-18 mother black bear with three yearlings nursing in light snow by MHolland 1077

Female Black Bears mate every two years. Their young are born in January or February and  they stay with their mother for the first year and a half of their lives. Although many sources state that cubs are weaned during their first summer, I discovered firsthand that young bears continue to nurse well into their second year (even though they’ve been eating solid food since they were a few months old).

Two different times while I was within a stone’s throw of her, the mother lay down on the ground and her yearlings proceeded to nurse. Soon, in May or June, shortly before she mates, the mother will drive her yearlings away, forcing them to disperse. Life’s lessons have been taught. By their second spring the yearlings have learned the basics from their mother: what to eat and where to find it, how to defend themselves, where to find safety and how to interact and communicate with other black bears. and they should be able to survive on their own.

Naturally Curious is supported by donations. If you choose to contribute, you may go to https://naturallycuriouswithmaryholland.wordpress.com and click on the yellow “donate” button.


Black Bear Yearlings Active

3-30-18 yearling black bears mock fighting 1276

Just like other young mammals, young Black Bears are highly energetic. When they aren’t sleeping, they can be found wrestling, biting, grooming, climbing and playing hard with each other. All of these activities, including the pictured yearlings mock-fighting, equip them with necessary survival skills.

Naturally Curious is supported by donations. If you choose to contribute, you may go to https://naturallycuriouswithmaryholland.wordpress.com and click on the yellow “donate” button.


Exploring With Senses

4-6-18 black bear yearling on back 1058The yearlings were constantly engaged in exploration and play that makes use of all of their senses – playing with sticks, needles and anything else they can find to manipulate with their huge paws, chewing saplings, smelling everything from chewed sticks to each other’s scat, clawing, biting and rubbing on tree trunks, and even approaching me in order to see exactly who and what I am. (Several times I had to shoo one of them away, for fear their mother might object to its close proximity to me.) Some of this exploration serves as the beginning of scent-marking that they will use to communicate with other bears their entire lives, while some of it appears to be just plain fun.

Naturally Curious is supported by donations. If you choose to contribute, you may go to https://naturallycuriouswithmaryholland.wordpress.com and click on the yellow “donate” button.


Tolerant Black Bear Mothers

3-28-17 black bears playing 1368

The yearlings continually challenge their mother’s patience as well as each other’s to see just how much will be tolerated. They climb on, bite, claw and test their mother in much the same manner as toddlers do their (human) mothers. At the same time, when she demands that they follow her instructions, such as climbing a tree when danger approaches, they immediately obey. (Photo: mother bear (lying down) indulging her playful yearling)

Naturally Curious is supported by donations. If you choose to contribute, you may go to https://naturallycuriouswithmaryholland.wordpress.com and click on the yellow “donate” button.

 


Black Bears Emerging From Hibernation

3-26-18 black bears sleeping 1545

A year ago, in April 2017, while following Black Bear tracks in New Hampshire, I had the good fortune to encounter the bears themselves. Because Black Bears have started coming out of hibernation (April is when most do so) I felt it was timely to share some of my photographs and observations of that encounter. (I did not do so a year ago for fear of bringing attention to and thereby disturbing these bears.)  As I followed the bear tracks, I eventually came upon a refuge, or “babysitter,” tree – where bears rest and cubs/yearlings take refuge when their mother goes off foraging or when she senses danger. I had read about such trees, but never discovered one myself. It was very recognizable — a very large White Pine surrounded on the ground by bear scat and gnawed saplings – fresh signs that bears frequented this area. At the base of the tree were several large “bowls” or indentations in the pine needles that looked as if large animals might have bedded down repeatedly in them, forming nests.

I continued tracking, eventually turning around to head back to where I entered the woods. On my return I passed by the babysitter tree again. To my utter delight I discovered a mother bear with her three yearlings fast asleep in the beds at the base of the tree. It was snowing lightly, and I surmised that this family had recently emerged from their deep winter’s sleep and was still a bit groggy. (Adult males are the first to emerge; females with cubs are the last.) While the yearlings slept on, the mother opened her eyes and decided to tolerate my presence for the next couple of hours. In Naturally Curious posts this week and next, I will share this once-in-a-lifetime experience with you as well as the behavioral observations I made.

Naturally Curious is supported by donations. If you choose to contribute, you may go to https://naturallycuriouswithmaryholland.wordpress.com and click on the yellow “donate” button.


Beechnuts & Black Bears

11-22-17 black bear scat and beechnuts 049A7821One need look no further than this Black Bear scat to know that American Beech (Fagus grandifolia) nuts (hard mast) are a preferred food for Black Bears, both in the fall and spring. They are an important food source for other wildlife as well, including White-tailed Deer, Fishers, Wild Turkeys, Ruffed Grouse and many small mammals and birds.

There are very good reasons why beechnuts are a preferred food for so many creatures. They have about the same protein content as corn but five times the fat content. Compared to acorns, beechnuts have nearly twice as much crude protein, twice the fat of white oak acorns and about the same fat content as red oak acorns. Research on the importance of beech mast for Black Bear reproduction shows that in northern Maine, 22% of the female black bears that were reproductively available reproduced following falls when beechnut production was poor. The proportion of reproducing females increased to 80% following falls when beechnut production was high. (Photo:  Black Bear beechnut husk-filled scat, 1 1/2″ diameter)


Black Bears Raiding Brood

11-1-17 bear binging 049A7147Previously this fall I posted about Black Bears foraging ferociously in the fall in order to store fat (sometimes doubling their weight) before hibernating. That post showed an ant-infested tree that had been ripped apart. As winter approaches, signs of bears’ frenetic gorging (hyperphagia) increase dramatically. Protein-rich sources such as Bald-faced Hornet nests (suspended from branches) and Yellow Jacket nests (in cavities in the ground) are highly sought after.

If you look closely, you’ll see that the claws of the bear that attempted to raid the hornet nest (suspended ten feet above the ground) were able to reach just the bottom portion of the nest, tearing the outer multi-layered, paper envelope but not reaching the brood-containing cells within. The Yellow Jacket cells containing brood (eggs, larvae and pupae), on the other hand, were all removed from the ground nest and consumed. All that remains is a portion of the outer envelope and a few adults.

 


Black Bears Foraging

9-4-17 bear tree2 049A4107

This is the time of year when Black Bears are looking for every available source of food in order to bulk up before entering hibernation. During this period of gorging (hyperphagia) Black Bears consume large quantities of fruits, berries, nuts, grasses, roots and insects.

In particular, they favor the brood (larvae and pupae) of ants, due to their relatively high content of fat and protein. Black Bears find brood by detecting the pheromones and other chemicals such as formic acid that ants use for communication and defense. Research has confirmed that Black Bears will dig up as many as 200 ant colonies a day, flipping rocks, moss and leaf litter over and tearing apart logs, stumps and snags (such as the one pictured), using their canine teeth and claws to gain access to the ants. Once they have torn apart the stump or snag, they use their long, sticky tongues to gather brood. Anthills are avoided except for when Black Bears are extremely hungry, due to the fact that bears prefer not to get a lot of soil or sand mixed in with the brood they’re eating. (Thanks to Virginia Barlow for photo op.)


This Year’s Black Bear Cubs Growing Up Fast

5-8-17 black bear cub 054

It’s hard to believe that four months ago when it was born this Black Bear cub weighed less than a pound and measured about eight inches in length! Most Black Bears mate in June, but because of delayed implantation their fertilized eggs don’t implant in the uterine wall and the embryos don’t begin developing until the fall (if the mother has had a sufficiently nutritional diet), just as the mother is entering hibernation.

The cubs are born in January, after only a few months inside their mother. They are just a fraction of one percent of the mother bear’s weight, compared to an average human baby that is about seven percent of its mother’s weight. The cubs nurse constantly for the next four months (during which time their mother is not eating or drinking).  The fat content of Black Bear milk can be as high as 20-25 percent. Human milk is comparable to cows’ milk, generally ranging between three and five percent fat. (A biologist who had the opportunity to sample Black Bear milk reported that it was similar in taste to sweetened condensed milk.)

In April, when the cubs emerge from their den, they weigh about six pounds.  Milk production and intake now increases four-fold. Peak lactation (45 ounces of milk per day per cub) occurs in June and July. As a result, the cubs have a huge growth spurt their first summer and will weigh between 40 and 60 pounds by the end of it.

Naturally Curious is supported by donations. If you choose to contribute, you may go to http://www.naturallycuriouswithmaryholland.wordpress.com and click on the yellow “donate” button.


Woodland Recycler

4-7-17 chickadee on scat 116The ability to find food is crucial for all creatures.  It involves looking in every potential location, including the waste material of other animals.  Nothing goes to waste in the natural world, and I was fortunate to observe an example of this recycling phenomenon recently in bear-inhabited woodlands.

Even though feeding birds is discouraged at this time of year due to the seeds’ appeal to hungry, emerging Black Bears, many find it a hard habit to stop. Inevitably Black Bears will smell the seeds in feeders and help themselves to them.  If this continues long enough, the bears will become habituated and eventually this can lead to their being considered a nuisance, which can lead to their demise. Thus, it’s best to stop feeding birds now that Black Bears have emerged from hibernation.

That said, those who continue to fill feeders in the spring and have had them raided by bears need not fear that their birds are without recourse should they find the feeders empty or missing. Much of what goes in comes out, and bears deposit their seed-laden scat throughout the woods, creating ground “feeders” for all kinds of creatures. In this instance, a Black-capped Chickadee repeatedly helped itself to uncracked sunflower seeds amongst a great deal of millet and sunflower seed husks in the scat of a Black Bear.

This post is dedicated to Sadie Brown, Solid Waste & Recycling Coordinator for the town of Melrose, MA.

Naturally Curious is supported by donations. If you choose to contribute, you may go to http://www.naturallycuriouswithmaryholland.wordpress.com and click on the yellow “donate” button.


Black Bears Emerging From Hibernation

3-3-17-black-bear-002

Time to take in bird feeders, at least at night. Black Bear sightings are being reported throughout northern New England, a bit earlier than usual probably due to the erratic weather we’ve been having. Adult males emerge from their dens first, females with cubs  last – the opposite order in which they entered in the fall.

Having survived the winter by living off the fat they accumulated last fall, Black Bears weigh considerably less upon waking. Males will typically drop between 15 and 30 percent of their body weight, while lactating mothers can lose up to 40 percent. Even so, for the first two or three weeks following hibernation, bears eat and drink less than they normally do, while their metabolism adjusts to the changes. This is referred to as “walking hibernation” by some biologists. Once normal activity resumes, and until herbaceous green shoots appear in wetlands, bird feeders  are a main attraction.

Naturally Curious is supported by donations. If you choose to contribute, you may go to http://www.naturallycuriouswithmaryholland.wordpress.com and click on the yellow “donate” button.


Black Bears Gorging

10-28-16-corn-203Black bears are omnivores as well as opportunists.  They will eat almost anything that they can find, but the majority of their diet consists of grasses, roots, berries, nuts and insects (particularly the larvae).  As the days cool, and the time for hibernation nears, black bears enter a stage called “hyperphagia,” which literally means “excessive eating.”  They forage practically non-stop — up to 20 hours a day, building up fat reserves for hibernation, increasing their body weight up to 100% in some extreme cases.  Their daily food intake goes from 8,000 to 15-20,000 calories. Occasionally their eyes are bigger than their stomachs, and all that they’ve eaten comes back up.  Pictured is the aftermath of a Black Bear’s orgy in a cornfield.

If you  share a bear’s territory, be forewarned that they have excellent memories, especially for food sources.  Be sure not to leave food scraps or pet food outside and either delay feeding birds until bears are hibernating (late December would be safe most years) or take your feeders in at night.

NOTE:  Orders for 2017 Naturally Curious calendars must be received by October 31.

Naturally Curious is supported by donations. If you choose to contribute, you may go to http://www.naturallycuriouswithmaryholland.wordpress.com and click on the yellow “donate” button.

 


Black Bear Lactation

2-11-16  black bears IMG_0380Black Bear cubs are born in late January or February, weighing about eight ounces. The newborn cub(s) immediately crawl to their mother’s teats (she has six) closest to her pelvis to nurse. Later, as the cubs get older, they nurse from the top four and the mother often “switches off” production in the bottom two. At birth a Black Bear cub weighs half to three-quarters of a pound, and when it emerges from the den in April it averages about six pounds.

Most hibernating mammals are not pregnant. The fact that Black Bear cubs are born in late January or February, and the mother bear nurses them for two or three months while she is not eating or drinking is a phenomenon in and of itself – just ask any ravenous nursing human mother.

Milk production and intake increases four-fold after the cubs emerge from the den. At peak lactation (June and July) a black bear cub consumes about 30 ounces of milk a day. If a bear has two or three cubs, that means she must produce two or three quarts of milk a day. The milk of Black Bears is very rich: human (and cow) milk is about three to five percent fat while Black Bear milk is around 20 to 25 percent fat. In addition, the carbohydrate composition of the Black Bear mother’s milk while she is nursing in the den is relatively high compared to the carbohydrate composition found in milk after denning; the protein content after denning is double that of milk produced during hibernation.  At roughly six to eight months of age, Black Bear cubs are weaned. (Thanks to Ben Kilham for photo op.)

Naturally Curious is supported by donations. If you choose to contribute, you may go to http://www.naturallycuriouswithmaryholland.wordpress.com and click on the yellow “donate” button.


Black Bears In No Hurry to Den This Year

11-16-15 black bear apple scat 026Bountiful acorn and apple crops have enabled black bears to delay denning this fall, as this recently-discovered apple-filled bear scat attests to. Denning is triggered by a seasonal shortage of food, low temperatures, and snow cover on the ground. When these conditions cause bears to den, they typically stay within their summer range boundaries. On average black bears enter their dens in November and emerge in April, but this varies considerably with crop and temperature conditions.

Denning sequence usually begins with yearlings, followed by pregnant females, then solitary females, females with cubs, adult males, and last, subadults (not sexually mature) of both sexes. Most dens are excavated below ground, and on well-drained, upland sites. Rarely are they re-used in consecutive years. Adult males are the first to emerge in the spring, followed by subadult males and females, then females accompanied by yearlings, and finally, females with cubs of the year.

Naturally Curious is supported by donations. If you choose to contribute, you may go to http://www.naturallycuriouswithmaryholland.wordpress.com and click on the yellow “donate” button.


Black Bears Seeking Protein

9-2 hornet nest torn by bear 083Although insects and animal matter make up less than 10% of the annual black bear diet, they are a crucial part of it. Black bears get most of their animal protein from ant brood, hornet larvae, tent caterpillars, march fly larvae, grubs (especially June beetle grubs), and snow fleas. Among the most preferred sources are bee and hornet larvae. Berries and other fruit don’t have a great amount of protein, but they do have some (blackberries = 2 grams of protein per cup). If the summer berry crops fail, insect brood is especially important, especially at this time of year, when bears are seeking protein, fats and carbohydrates, putting on as much as 30 pounds per week to sustain themselves through the coming months of hibernation.

When tearing apart a beehive, yellow jacket nest or bald-faced hornet nest (see photo), bears do get stung, particularly on their ears and faces (their fur is fairly impenetrable). Apparently the reward is worth the aggravation. After filling themselves with brood (and in some cases, honey) black bears shake vigorously in order to rid themselves of any insects that are caught in their fur.(Thanks to Alfred Balch for photo op.)

Naturally Curious is supported by donations. If you choose to contribute, you may go to http://www.naturallycuriouswithmaryholland.wordpress.com and click on the yellow “donate”
button.


Black Bears Marking Territory & Mating

6-30 black bear sign 032Black Bear (Ursus americanus) breeding season begins in May and lasts until early July, with mating occurring mainly during June. The female traverses her territory at three times her normal rate during this time, laying down a scent trail which the male follows. Both male and female periodically intentionally deposit their scent by straddling vegetation, breaking off small limbs and biting, scratching and rubbing on trees (and telephone poles if available). Tree species often used for marking include White Birch, Balsam Fir, Striped Maple and Red Pine. When contact between the bears is eventually made, they nuzzle and chew on each other’s head and neck and may even wrestle a little. Mating occurs repeatedly for several days. (Thanks to Alfred Balch for photo op.)

Naturally Curious is supported by donations. If you choose to contribute, you may go to http://www.naturallycuriouswithmaryholland.wordpress.com and click on the yellow “donate” button.


Black Bear Yearlings Soon To Be On Their Own

5-19-15  black bears 067Female Black Bears become sexually mature at three-and-a-half years of age. They breed in June and give birth in January or February (delayed implantation). Black Bears have a 2-year reproduction cycle: the cubs remain in the custody of their mother for roughly a year and a half, during which time the mother doesn’t mate. In May or June of the year following their birth, when they are 16 or 17 months old, the yearlings become independent and go off on their own — – just prior to black bear mating season. (Thanks to Jill and Bryan Marquard for photo op.)

Naturally Curious is supported by donations. If you choose to contribute, you may go to http://www.naturallycuriouswithmaryholland.wordpress.com and click on the yellow “donate” button.


Black Bear Dens

2-25-15 bear dens1Black bears den in a range of locations, including under logs and stumps, under the branches of a fallen tree, and inside caves and hollow trees. Most adult black bears are not completely protected from the elements while they are hibernating and/or raising cubs, as there is usually a fairly large opening and the bear is exposed to the cold air. The amount of exposure can vary tremendously, from a relatively protected hollow under a log to complete exposure within a dense thicket or stand of conifers. Pictured are two black bear dens where cubs were raised; one is under a fallen tree and the other is in the middle of a stand of spruces.

Naturally Curious is supported by donations. If you choose to contribute, you may go to http://www.naturallycuriouswithmaryholland.wordpress.com and click on the yellow “donate” button.