GB2255217A - Bird scaring apparatus - Google Patents

Abstract

Apparatus for scaring predators, such as birds, composes an infra-red detector 13 for detecting the presence of a predator in a predetermined region. The detector 13 produces an output signal when a predator is detected, the output signal being used to trigger an alarm response, such as a high-pitched sound, to frighten the predator. <IMAGE>

Description

BIRD SCARING APPARATUS This invention relates to apparatus for scaring predatory and/or scavenging creatures such as birds. The apparatus of the invention has particular applications in frightening predatory birds (such as gulls and cormorants) in the region of, for example, a fish pen such as a trout pen, and scavenging birds (such as pigeons) in, for example, a barn or grain loft.

Breeders of fish such as trout or salmon provide pens for keeping the fish captive. Typically, such a pen has portions above and below the water line, the lower portion defining an underwater chamber for constraining the fish, and the upper portion providing some protection from predatory birds. It is still possible, however, for predatory birds to alight on the upper pen portion and poach fish with their beaks. The droppings from such birds (having a high nitrate content) also cause a problem as they tend to be confined within such a pen, causing a drop in the oxygen level of the water within the pen, and this can lead to diseased fish, for example Spinners Disease can result.

Similarly, in garden ponds or lakes, for example, fish can be vulnerable to predators such as herons or even on occasion cats. In addition, fish have been the victims of poachers. With the introduction of more exotic types of fish, e.g. Koi, these may even be stolen for resale to other fish collectors.

The aim of the invention is to provide apparatus for scaring birds or other predators.

The present invention provides apparatus for scaring predators, the apparatus comprising detection means for detecting the presence of a predator in a predetermined region and for producing an output signal when a predator is detected, and means for producing an alarm response to frighten the predator.

Advantageously, the apparatus further comprises control means for controlling the sound-production means, the control means being actuated by the output signal.

Preferably, the detection means is a passive infra-red detector. Conveniently, the sensitivity of the infra-red detector is adjustable, whereby the detector will only provide an output signal when a bird above a predetermined size (and hence body heat) enters the predetermined region.

In a preferred embodiment, a piezo-speaker/driver unit constitutes the sound-production means. Conveniently, the piezo-speaker/driver unit is a multi-stage unit, that is to say it has a plurality of drive circuits each of which is pre-set to produce sound of a respective predetermined frequency range from the piezo-speaker. Alternatively, a tape deck/amplifier unit constitutes the sound-production means. In this case, the tape deck may be set up to play a tape of the call of a peregrine falcon. In either case, the arrangement is preferably such that sound is emitted in short bursts.

Advantageously, the apparatus further comprises a timer/relay unit for initiating the production of sound and for terminating sound production a predetermined time interval later.

The invention also provides a pen for constraining fish within a perimeter wall thereof, the pen being provided with at least one bird scaring unit as defined above.

The invention will now be described in greater detail, by way of example, with reference to the accompanying drawings, in which: FIGURE 1 is a plan view of a trout pen provided with two bird scaring units constructed in accordance with the invention; FIGURE 2 is a side elevation of the trout pen and bird scaring units of Figure 1; FIGURE 3 is a front elevation of one of the units of Figures 1 and 2; FIGURE 4 is a side elevation, partially broken away, of the unit of Figure 3; FIGURE 5 is a block circuit diagram of the unit of Figures 3 and 4; FIGURE 6 is a perspective view of a modified form of bird scaring unit for use with the trout pen of Figures 1 and 2; FIGURE 7 shows a pond together with another form of bird scaring unit constructed in accordance with the invention, the unit being housed within the body of a replica heron;; FIGURE 8 shows an arrangement for the heron and unit of Figure 7 in more detail; and FIGURE 9 is a block circuit diagram of the unit of Figures 7 and 8.

Referring to the drawings, Figures 1 and 2 show a trout pen, indicated generally by the reference numeral 1, having an upper portion 2 and a lower portion 3. The pen 1 is such that the upper portion 2 lies above the water level 4 of a pond, river or other stretch of water, and such that the lower portion 3 is submerged, when the pen floats thereon. The pen 1 can be anchored to the edge of a pond, to the bank of a river or to the river or pond bed by conventional means (not shown).

The upper pen portion 2 is generally rectangular, typically 25 feet by 15 feet, and has vertical walls 2a and a horizontal upper wall (or rim) 2b. The upper portion 2 is joined to the lower portion 3 by means of a buoyant pontoon 5. The lower pen portion 3 is also of rectangular configuration, having vertical walls 3a. The lower portion 3 thus provides an underwater chamber for retaining trout, and the upper portion 2 helps protect the trout from predatory creatures such as birds, cats and even human beings.

A respective bird scaring unit 11 is fixed to each of a pair of opposite corners of the rim 2b of the upper pen portion 2. Each of these units 11 (see Fig. 3) has a waterproof housing 12 which carries a passive infra-red detector 13, and houses a piezo-speaker/driver unit 14, a 12 volt dry battery cell 15, a timer/relay unit 16, and a voltmeter 17 for indicating the condition of the battery.

A solar cell 18 is provided on the top of the housing 12 for topping up the charge of the battery 15. A key-operated switch 19 is provided for switching the unit 11 on and off, and a tamper sensor 20 (see Fig. 4) is also provided for activating the speaker/driver unit 14 to emit a warning sound in the event of a poacher tampering with the unit.

The detector 13 is connected to a control unit 21 (see Fig. 4), and is arranged to scan an area of the pen 1, typically within an angular aperture of 1450 emanating from the detector. The control unit 21 is controllable to vary the sensitivity of the detector 13, so that the detector senses the body (infra-red) heat only of creatures above a certain size. Consequently, the unit 11 is not triggered by harmless small birds such as sparrows. This sensitivity control also prevents the unit 11 being triggered by the movement of trout (or other fish) within the pen 1. Very slowly changing heat sources such as the affects during sunrise or sunset will likewise fail to trigger the unit 11.

In use, when the detector 13 senses the body heat of a large creature (such as a cormorant or a gull), the control unit 21 causes the timer/relay unit 16 to operate, and this activates the piezo-speaker/driver unit 14 to emit a series of pulses of high volume (120 dB to 130 dB) sound.

The drive circuits of the speaker unit 14 can be factory set to emit sounds at different frequencies, depending upon the type or types of birds to be scared. In this connection, it should be noted that different birds have different hearing frequency ranges, so different frequencies are preferably used to frighten different birds. Although not shown, the speaker of the unit 14 has three or four stages (the drive circuits of which can be pre-set to drive the speaker at different frequencies), so that the speaker unit is effective to scare a wide range of predatory birds. One or more of the frequencies used may be in the ultra-sound frequency range.

The timer/relay unit 16 is effective to reset the system (that is to say to turn it off) after a predetermined period of time, typically 15 to 25 seconds.

This unit 16 also ensures that sound is emitted in pulses rather than as a continuous sound, it having been found that this is more effective for scaring birds.

Figure 6 shows a modified form of bird scaring unit 31. This unit 31 is similar to the unit 11 and so like reference numerals will be used for like parts. The unit 31 has, however, a tape deck/amplifier unit 32 and a loudspeaker 33 in place of the piezo-speaker/driver unit 14. The unit 32 and the loudspeaker 33 can be housed within the unit 31 instead of being external thereto as shown in Figure 6. In either case, when a creature such as a gull or cormorant is detected by the detector 13, the timer/relay unit 16 is triggered by the control unit (not shown, but similar to the control unit 21 of Figure 5). Once triggered, the unit 16 sends a control signal to the tape deck/amplifier unit 32 which is supplied with a tape of the call of a peregrine falcon.After a predetermined period of time (typically 15 to 25 seconds, the timer/relay unit 16 sends a further control signal to the tape deck/amplifier unit 32 to switch it off. As with the first embodiment, the tape of the peregrine falcon call is such that a series of calls are transmitted rather than a continuous call. This form of bird scaring unit is very effective, as practically all birds are terrified of peregrine falcons.

It will be apparent that modifications could be made to the bird scaring units described above. For example, because of the fear most birds have of peregrine falcons, a dummy peregrine falcon (for example with outstretched wings) could be positioned in the vicinity of the units, for example on the upper rim 2b of the trout pen 1.

It will also be appreciated that the bird scaring units could be used to protect pens for other types of fish. For example, for a salmon pen (which is typically about half the size of a football pitch), four units would be used, one at each corner. It would also be possible to use bird scaring units of the types described to deter scavenging birds (such as pigeons) in barns and grain lofts. In the latter case, a bird scaring unit would preferably be positioned where pigeons tend to congregate, for example near the motor of a grain lift or an aerator.

Other possible uses are to frighten birds away from the tops of buildings, TV masts, etc., where bird droppings cause problems.

Figure 7 shows another form of bird scaring unit 41, this unit being associated with a pond 42 with a stone periphery 43 and water 44 contained therein. The unit 41 is housed within the body of a replica heron 45. The heron 45 can be fabricated from suitable plastics material, for example. The heron 45 is supported on a stand 46 which replicates the heron's legs, and is typically adjustable and terminates in a heavy flat base 47 to ensure the heron remains upright even in windy weather.

In an alternative configuration (not shown) the stand 46 terminates in a spike so that it can be firmly driven into the ground, typically where soft banks to the pond are utilised.

An aperture 45a is provided within the body of the heron 45, the aperture providing an opening or window for a detector element 48 to scan the detection area. The detector 48 is preferably of the passive infra-red type, and the heron 45 is placed in such a position, and at such an angle, as to allow the detector to scan the pond 42 in the region of its surface, typically within an angular aperture of 1450 emanating from the detector 48.

The detector 48 is connected to a control circuit board 49 (see Figure 9) which determines when the detector 48 senses changes in infra-red energy caused by the movement of a body through the area of detection. Tests have shown that the detector 48 is sensitive enough to detect herons or cats within the water area, yet is resilient to false alarms. As with the earlier embodiments, the movement of fish below the surface of the water does not cause the alarm to operate. Very slowly changing heat sources, such as the effects during sunrise or sunset will likewise not cause activation of the alarm.

The triggering of the detector 48 operates a relay 50 and causes a siren 51 (equivalent to the piezospeaker/driver unit 14) to be triggered. The siren 51 can typically be a high pitched siren with a high power output.

To prevent continuous siren operation, a timer 52 is incorporated which resets the system after a predetermined period (e.g. 5 minutes). This allows the system to be rearmed should the intruder return.

The system can be powered by the mains, but, for the sake of safety, a step-down transformer should be employed to reduce the voltage in the region of the water to a safe value (e.g. 12 volts).

Where the site is remote from mains electricity, or as an alternative, the system can be directly powered from a portable power source 53 (e.g. a 12 volt gel-type battery).

Such a battery can be periodically re-charged from the mains. Where the alarm is intended to be in a remote or otherwise unattended location, an internal battery may not provide sufficient long term power and, in such a case, the power source 53 may be too large to be accommodated, and will thus be located adjacent to the heron 45. In this case, the power source 53 will be connected to the heron 45 by an armoured electric cable. In such circumstances, the power source 53 will preferably be housed within a lockable container which is suitably anchored to the ground. A small internal battery could also be included in the heron 45 to sound the alarm, for example should the external battery be disconnected.

As the power consumption of the system in the nontriggered mode is only a few milliamps, a solar panel 54 on the back of the heron 45 can be used to replenish at least part of the power consumed by the circuit, dependent on weather conditions. The circuit is arranged to operate both during the day and at night to guard against different types of animals, birds or poachers.

The siren 51 can be supplemented, if required, by other deterrents such as lights or sounders outside the human audible spectrum.

Preferably, the heron control circuit 49 includes a sensor 55 within the heron housing (e.g. a mercury switch) which will cause the alarm to sound if movement or tampering of the heron 45 is attempted by vandals or other intruders behind the field of view of the infra-red detector 48.

The heron 45 is arranged to be positioned in a location which looks attractive but, at the same time, scans the desired stretch of water.

In a modified arrangement, the heron 45 may be provided with LED eyes which light up when the detector 48 senses a predator, thereby providing a more realistic impression of the presence of a heron.

Where very large stretches of water are to be protected, more than one alarm can be positioned so that respective sectors of the stretch of water are protected to ensure sufficient coverage is provided.

It will be appreciated that the bird scaring units 11 and 31 of the earlier described embodiments could also be housed in replica herons. It will also be appreciated that, instead of using high-pitched or peregrine falcon sounds to frighten predatory birds, controlled detonations could be used. For example, the speaker unit 14, the unit 32 or the siren 51 could be replaced by a revolver loaded with blanks, the revolver being actuated by a solenoid and a relay. Such an arrangement may be preferable in some situations where predatory birds get used to high-pitched sounds - they never get used to the noise of a gun. It would also be possible to change the type of sound used to scare on a regular basis, thereby reducing the chances of predatory birds getting used to any one type of noise.

It would also be possible to modify each of the detectors 13 and 48 to operate on a two-stage basis. For example, the circuits can be modified so that a first infra-red detection does not trigger the alarm. Instead, the system is automatically re-armed, and the arrangement is such that a subsequent detection triggers the alarm. The advantage of this modification is that the system is less likely to be triggered by non-predatory birds, such as sparrows, flying across the field of view of the detectors.

The system will still sense the continued presence of a predator bird which will stay in the detection field for long enough to be sensed twice.

Claims (14)

CLAIMS:

1. Apparatus for scaring predators, the apparatus comprising detection means for detecting the presence of a predator in a predetermined region and for producing an output signal when a predator is detected, and means for producing an alarm response to frighten the predator.

2. Apparatus as claimed in claim 1, further comprising control means for controlling the alarm response producing means, the control means being actuated by the output signal.

3. Apparatus as claimed in claim 1 or claim 2, wherein the detection means is a passive infra-red detector.

4. Apparatus as claimed in claim 3, wherein the sensitivity of the infra-red detector is adjustable, whereby the detector will only provide an output signal when a predator above a predetermined size (and hence body heat) enters the predetermined region.

5. Apparatus as claimed in any one of claims 1 to 4, wherein sound-production means constitutes the means for producing an alarm response.

6. Apparatus as claimed in claim 5, wherein a piezospeaker/driver unit constitutes the sound-production means.

7. Apparatus as claimed in claim 6, wherein the piezospeaker/driver unit is a multi-stage unit, having a plurality of drive circuits each of which is pre-set to produce sound of a respective predetermined frequency range from the piezo-speaker.

8. Apparatus as claimed in claim 5, wherein a tape deck/amplifier unit constitutes the sound production means.

9. Apparatus as claimed in claim 8, wherein the tape deck is set up to play a tape of the call of a peregrine falcon.

10. Apparatus as claimed in any one of claims 6 to 9, wherein the arrangement is such that sound is emitted in short bursts.

11. Apparatus as claimed in any one of claims 1 to 10, further comprising a timer/relay unit for initiating the production of the alarm response, and for terminating the alarm response production a predetermined time interval later.

12. Apparatus for scaring predators substantially as hereinbefore described with reference to, and as illustrated by, Figures 1 to 5, Figures 1 to 5 as modified by Figure 6, or Figures 7 to 9 of the accompanying drawings.

13. A pen for constraining fish within a perimeter wall thereof, the pen being provided with at least one bird scaring unit as claimed in any one of claims 1 to 12.

14. A fish protection system comprising a housing in the shape of a bird, and predator scaring apparatus mounted in the housing, the predator scaring apparatus being as claimed in any one of claims 1 to 12.