The first day of fall was last Friday, September 22nd. Just down the street, a Sugar Maple has already started to change color! The best fall colors happen after a spring and summer that are somewhat wet, followed by a sunny autumn with warm days and cool, but frostless, nights.
As the nights get longer in the fall, the transportation of chlorophyll from the leaf to the branch, and from the roots to the leaves becomes blocked. As the chlorophyll is blocked from the leaves, it disappears completely.
This lack of green chlorophyll allows the yellow (xanthophylls) and orange (carotenoids) pigments to be visible. The red and purple pigments (anthocyanins) are manufactured from the sugars that are trapped in the leaf. These pigments are what cause the vivid color changes in leaves!
So far we've had the perfect weather for vivid fall colors! We just need a little more rain to keep the leaves from drying up! Hopefully rain will be forecasted in the near future!
Black Bear - Ursus americanus
Black Bears
I finally saw a Black Bear! A friend of mine had been chasing this bear away from his house, when I came across them! It was a small to medium size bear, probably about a year old. It climbed up a small tree and stayed for a while, but eventually climbed down and ran off! Usually, Black Bears are active at night, so I was lucky to see this one during the day!
The bears have been causing havoc in our neighborhood, dumping over trash cans, breaking into unoccupied sheds, trashing my neighbor's outdoor kitchen (her freezer AND refrigerator!), eating produce out of gardens, as well as climbing and breaking fruit trees and grapevines! Sheesh!
During the Fall, Black Bears are busy eating as much as they can and building up a layer of fat to last them through the winter. Black Bears are considered highly efficient hibernators. They can exist in a dormant state without eating, drinking, or producing body wastes for up to 7.5 months!!! Hibernation is a complicated process in mammals. I found the following summary of hibernation at www.denali.org/denalis-natural-history/black-bear-hibernation/.
"Hibernation is the mechanism that black bears use to conserve energy and reduce their internal fires of metabolism. For a long time people thought that the bears slept through the winter in cozy dens and emerged in the spring fully charged.
However, far from being a long, uninterrupted sleep, hibernation consists of periods of sleep punctuated by periods of arousal. Sleep time is long during the dead of winter but is shorter at the beginning and end of the season. To prepare for this long season black bears feed ravenously from midsummer through the end of autumn, gleaning up to 20 thousand calories in a day. Bears are omnivores and will eat meat too, including ground squirrels, carrion and whatever they can find. By the end of autumn, a black bear will have added about 4 or 5 inches of body fat and more than doubled the insulation provided by its pelt.
As the bear enters hibernation, its metabolic processes such as body temperature, heart rate, and respiratory rate are reduced. But bears do not lower the body temperature as much as once thought. Their hibernation temperature is around 88 degrees and waking temperature is 100 degrees F. This relatively high sleeping temperature allows black bears to become fully alert if aroused, perhaps to enable the bear to protect itself from predators and other dangers without unnecessarily taxing their energy reserves. Over the course of a hibernating season it is thought that black bears use approximately 4 thousand calories a day, which results in a weight loss of about 20 percent of it body weight by spring."
WOW!!! No wonder they've been eating everything they can!
Black Bear - Ursus americanus
Gray Squirrel - Sciurus griseus
Gray Squirrel
I watched this Gray Squirrel peel and bury several Black Walnuts a few days ago. Unlike Black Bears, they remain active in winter and forage for food daily. They are called "scatter hoarders" as they stash food for winter in many different areas, instead of in one main area.
Columbian Black-tailed Deer (left) - Odocoileus hemionus columbianus
California Mule Deer (two on right) - Odocoileus hemionus californicus
Mule Deer
It's been confirmed that these deer are the same genus and species, but different subspecies! I posted this photo on www.iNaturalist.org and got an immediate response! Apparently they are both Mule Deer (Odocoileus hemionus) but different subspecies! The obvious difference is the ear size and tail markings. I'll try to get a photo of their tails the next time I see them! I find it really interesting that they are associating with each other! Mating season is coming up, and my neighbor saw 5 bucks walking together along the water ditch a few weeks ago! Hopefully, I'll get a photo of them as well!
Gray Fox - Urocyon cinereoargentus
Gray Fox Update!
I've learned, through observation, that our local foxes like to sun themselves in the morning! I got these photos two days ago around 9:30 in the morning, just after the sun had reached our canyon! So beautiful!!
Gray Fox - Urocyon cinereoargenteus
I was also lucky to watch this Gray Fox stalk, pounce, and shake an old towel that a bear probably dropped! It very slowly and cautiously approached the towel (dirty brown and fuzzy), then snapped it up and shook it lightning quick! I'll bet it was surprised when the towel remained inert! Curiosity satisfied, the fox returned to the sunny entrance to its den and proceeded to groom its fur! WOW!!! Wildlife in action!
Gray Fox - Urocyon cinereoargenteus
Canada Goose - Branta canadensis
River Update!
The Canada Geese are still living on the river! There is a group of 6 of them that feed off the algae on the underwater rocks. They mate for life, and maintain their family group throughout the year! Several generations have raised their goslings in our neighborhood! They'll be migrating down to the Central Valley, or further south, as the weather gets colder and temperatures drop! I lovely their stateliness and elegant posture!
Common Merganser - Mergus merganser
Yahoo! I saw the Common Merganser with her 3 ducklings yesterday! The ducklings look full grown! I am so happy that they have survived!!! I wasn't so sure they would make it, with a Great Blue Heron and River Otters in the neighborhood! Soon they will be flying down to the Central Valley, or the Southwest, to spend the winter!
Yahoo! I saw the Common Merganser with her 3 ducklings yesterday! The ducklings look full grown! I am so happy that they have survived!!! I wasn't so sure they would make it, with a Great Blue Heron and River Otters in the neighborhood! Soon they will be flying down to the Central Valley, or the Southwest, to spend the winter!
Rainbow Trout "Fry"- Oncorhynchus mykiss irideus
I found these tiny fish in a side-pool of the river this week. The don't look much bigger than they were in July! How long does it take for fish fry to mature? I'll do some research this week and let you know what I find out!
Common Green Darner - Anax junius
These dragonflies are still zooming over the river in big groups! My neighbor, who lives right by the river, had a lot of ladybugs show up in her yard this week. When the sun warmed the ladybugs up enough to fly, dragonflies zoomed in and caught them in the air! Most of the time the dragonflies dropped them, but some of them were eaten! Wow! I didn't know dragonflies ate ladybugs!
Jelly Fungus - Tremellaceae Conk - Polypore
It hasn't rained lately, and I haven't yet found any fungi on the forest floor. I did, however, come across the fungi above while we were hiking in the Lakes Basin this week. These fungi were growing on deadwood, and tree trunks, not on the forest floor! The jelly fungus was about as big as my thumbnail, but the conk was about 18" wide! Hopefully rain will come soon, and fungi will thrive!
What kind of insects are these?
If you guessed that the animal tracks pictured last week are Black Bear tracks, you're right!
Are the ladybugs back yet?
What's happening in the Garden?
And what about those birds that are year-round residents?
Check back next week for the answers
to these questions and more!
Your comments and questions are greatly appreciated!
Please email me at northyubanaturalist@gmail.com!
or
Click on the comments just below, to post a comment!
Thanks!
No comments:
Post a Comment