Ultrasonic noise is noise played at a very high frequency which can often be very harsh and sometimes even painful for squirrels and other rodents. There are lots of ultrasonic devices which you can purchase to deter squirrels.
One of the most important things to know about squirrels and other types of rodents is that they do not like unexpected noises. They're easily frightened by these types of unfamiliar and disconcerting sounds and will initially stay away from where they're coming from.
Natural Squirrel RepellentsSpread predator urine around your garden. Try sprinkling cayenne pepper, ground chili peppers, pepper flakes, and/or garlic pepper on and around your plants when they are ready to bloom. Birds can't taste capsaicin, so add some cayenne pepper to those bird feeders to deter squirrels.
High-frequency sounds have minimal effect on squirrels. Sound repellents may work well for short-term garden use, such as keeping squirrels out of a newly planted bed until the seedlings establish enough to resist damage, but they likely won't provide a long-term solution.
The high frequency sound devices operate by emanating high-pitched noise that is within a squirrels' range of hearing – about 25,000 hertz (cycles per second) but too high for human ears.
Small wind chimes can end up attracting squirrels instead of scaring them. It is not uncommon to see squirrels hanging on wind chimes.
Wind chimes can scare away squirrels but only temporarily. The sound created by the chimes can startle squirrels and cause them to run away. However, the squirrels will get used to the sound relatively quickly, so you'll need to replace them often with a different noise in order to keep them away.
Scare them away. Rodent-chasing dogs and motion-activated noisemakers, such as garden spinners, pinwheels, and aluminum pie tins, all make good squirrel deterrents.
In math, the symbol U represents the union of two sets, while upside-down U represents the intersection of the sets.
Here x represents values of the random variable X, μ is the mean of X, P(x) represents the corresponding probability, and symbol ∑ represents the sum of all products (x−μ)2P(x).