For our product, we needed to explore different types of detection and determent methods for birds. The problem of avian determent has been around for a while, particularly in the farm and airport related settings, so there is much research and experimentation done on large scale (.5-30 acres) area denial. There is less research on products on a smaller scale. Lastly, we also needed to research pricing and specifications for different solar panels and batteries.

 

Detection methods

 

There are two schools of thought here: the first, we need to detect the bird and then shoo it away. And the second, we just have to run our deterring device all the time, negating the need for detection. The second seems like the best choice, however, if our device needs a lot of energy to run, it may be better to wait for a bird, and then run our device. With this in mind, we studied different detection methods. Note that for most of these methods, they can be set off by both birds and humans/house pets, so a certain amount of sensor vision limiting may be required.

 

Infrared

For our price range, the only form of infrared detection cheap enough is the basic model, which only searches for changes in the infrared spectrum. All hot bodies emit infrared, so this could be a decent solution for detecting a quickly arriving bird.

 

Sonic

Sonic detectors search for large bodies in the immediate vicinity of the device. Sonic detection has approximately the same issues as infrared (sensitive to everything, not just birds), and may cost more depending on the model used.

 

Parallel Plate

This detection works on the principal of a capacitor. When a bird (which has a different dielectric constant than air) flies in between two plates, it changes the capacitance. We could use this change to signal when a small and large object comes between the plates (differentiating between humans and birds). However, the plates would have to be fairly large and high voltage, this would increase the material cost for the plates, require high voltage shielding, and generally would not be useful for our small solar panel run device.

 

Laser-Photocell

This system uses a laser tripwire setup across the main roost of the area in need of protection. When the laser is interrupted, the device will trigger. This system is fairly cheap and, depending on the geometry and functions of the area, will not be triggered by humans. It is, however, limited to roosting areas, so birds that will invade via the ground will not trigger the device.

 

Pressure/Button

In this setup, we would cover every roost with pressure sensors or button pads. This system would, depending on the sensor, become rather expensive. Again, we are limiting the area of detection to one dimensional roosts.

 

Camera

Using a cheap camera and software, we look for small moving objects on the screen. Essentially, this would be a motion sensor. With this setup, we could differentiate between large and small objects, only triggering when small objects enter the area. This device would, however, have difficulty distinguishing between small objects and large objects in the far background. In addition, it could also be sensitive to windy days (swaying trees, porch ornaments). Admittedly, this device would also have trouble distinguishing between house pets.

 

It should also be noted that, with some of these detectors, they are split into 2-4 parts. Many of these devices will need to have wires run between them.

 

Deterrent methods

Most of the deterrent methods presented here are based on products in the market today. A common theme in bird deterrence is that the more variation in devices in an environment, the more effective the entire system will work at providing bird deterrence over a designated area. Variety and unpredictability are key to reliably deterring birds. In general, for optimal effectiveness, we’ll need to use at least two different methods to reliably deter birds.

 

Mechanical/Physical Bird Deterrents

Common physical bird deterrents include types of roosting spike, rotating arms, and other small devices that create an uncomfortable environment for birds to loiter in on a localized scale. These can be said to be the most effective bird deterrents, as they physically prevent birds from landing in specific areas or condition birds to avoid them. However, this solution works poorly at providing protection over even small open areas, as a physical prevention method has a limited reach or limited installation environment.

 

Roosting Spikes

Roosting spikes have evolved into electrified tracks that shock any bird that lands on them. This has the same effect as roosting spikes as it physically prevents birds from being able to occupy that area, but also conditions birds to stay area from that area as well. A drawback of this method, like most physical deterrents, is that it works only in a user designated area, with no passive deterrent area of effect.

 

Mechanical motion

Mechanical motion deterrents work almost exclusively within their own area of operation, not being able to scare birds away that physically come in contact with the device. Birds adapt quickly to these types of continuous motion devices and learn to just avoid its physical area of effect, which makes these devices ineffective at providing any large scale protection from birds.

 

Water Sprinkler

Another sub-type of mechanical motion devices seen was a water-sprinkler powered motion sensing device that squirts birds with water. This device could provide adequate protection over a greater space than other mechanical devices, however, at the expense of always having a water hose attached to it.

 

The problem posed by bird deterrence is a hard one to solve, as birds adapt quickly to deterrence methods that do not have variation in their operation. Conditional methods, such as shock strips (or sticky paste) provide an effective tool but only in a localized area. The same can be said about mechanical motion devices, but outside their area of operations, effectiveness is very limited.

 

Auditory Determents

 

Sonic

Anything in the 20Hz-20kHz is considered sonic. This range can be separated into two categories, comprehendible, and startling. Startling has to deal with scaring the birds away with a loud sound (shotgun blanks, gas cannon). Comprehendible sounds have to deal with bird calls (particularly “danger” calls) and predator noises. Both of these methods have proven to be somewhat useful on a large scale (.5-30 acres). Comprehendible noises must have plenty of variety, otherwise birds will figure out that it may not be legitimate.

 

Ultrasonic

Unfortunately, most birds do not hear ultrasonic frequencies.

 

Infrasonic

The research on infrasonic sounds and how they affect birds is fairly new, but it has been tested and proven to be somewhat effective. Research has shown that birds like the carrier pigeon use infrasonic detection to map out areas around them. A blast of infrasonic sound may help to unease birds into not hanging around an area.

 

Visual Determents

 

Predatory

This involves making a mock predator and placing it in the vicinity in need of determent. Bird predators can be anything from a coyote to a great horned owl. You can increase the effectiveness of a predator model by placing another faux dead bird at its side, or in its grasp. The more lifelike the predator, the more likely birds will not suspect it is fake. This includes lifelike model movements and repositioning of the model every day or so. Scarecrows also fall under this category, and also have the same requirements for believability.

 

Reflectors

Metal or Mylar reflector tape is also widely used as a bird deterrent. Their metal sheen disorients birds. They also make noise as they blow in the wind, adding to the disorientation. The tape typically wears down over time, and needs to be replaced. This does not work on all birds, but apparently does work on most pest birds. It is also fairly cheap.

 

Solar Panel and Battery

Solar panels are used in many applications ranging from powering calculators to powering entire homes. There are three main types of solar panels including mono crystalline silicon, poly crystalline silicon and thin film solar cells. For this project the solar panel will be required to power motors or speakers to scare the birds away. Some examples that exist of using solar panels in devices to scare birds include solar powered owls where the head rotates using a motor powered by solar power. For our design we will use similar principals as this owl but with far more complex scaring tactics.

 

Some small motors run on the order of 400 mA of current. If a motor of this current ran for 1 hour continuously it would require 400 mAh of power. The motors for this project will be running for approximately 10 sec per minute under high load times meaning the motor could run for 6 hours at high load for400 mAh or 66.66 mAh used per hour of use. If the battery used to power this motor were a 12Ah battery it would be able to power this motor for 21 hours before needing to be recharged. In order to keep this battery charged without human interaction a solar panel will be incorporated. Solar panels are rated in mWh therefor assuming a 12 V system there will be a requirement of 800 mWh to be produced each hour or approximately 0.6 kWh per month. Assuming 4.5 hours of peak sun being in Montana, to allow this system to run continuously a solar panel that is at least 4 W is required.