WO2015061853A1

WO2015061853A1 - Method and apparatus for deterring birds

Info

Publication number: WO2015061853A1
Application number: PCT/AU2014/050320
Authority: WO
Inventors: Andy Bennett
Original assignee: Deakin University; Bhp Billiton Limited
Priority date: 2013-10-31
Filing date: 2014-10-29
Publication date: 2015-05-07

Abstract

Method and apparatus for deterring birds from occupying a space. Illumination is provided visible to birds entering the space, the illumination repetitively varying in intensity at a rate above the critical flicker fusion rate for humans, and below the critical flicker fusion rate for birds. The frequency may be substantially in the range 30 to 150 Hz

Description

, I -

METHOD AND APPARATUS FOR DETERRING BIRDS FIELD OF THE INVENTION This invention relates to method and apparatus for deterring birds from occupying a space. BACKGROUND OF THE INVENTION

The invention derives from the observation that birds are adverse to occupying a space where they are subjected to flickering light and that birds perceive repetitively varying light as flickering where the repetition rate is higher that the maximum rate at which humans perceive flicker rather than continuous lighting.

SUMMARY OF THE INVENTION

In one aspect the invention provides a method for deterring a bird from occupying a space, in which illumination is provided visible to the bird within the space, the illumination repetitively varying in intensity at a rate substantially in the range 30 to 150 Hz, The invention als -provides a method for deterring a bird from occupying a space, in which illumination is provided visible to the bird within the space, the illumination repetitively varying the intensity at a rate to be aversive to the bird sufficient to cause the bird to be deterred, and above the critical fusion rate exhibited by humans. Preferably the rate is in the range of 30 to 150 Hz.

The invention further provides a method of protecting a space from a bird, in which illumination is provided, located at or adjacent the space to be observable by the bird, and effective to induce in the bird aversion to entering the space. The invention further provides a method for deterring a bird from occupying a space, in which illumination is provided visible to the bird entering the space, the illumination _ ~ repetitively varying in intensity at a rate above the critical flicker fusion rate for humans, and belo the critical flicker fusion rate for the bird. Preferably the rate is in the range 30 to 150 Hz. The invention further provides an apparatus for deterring a bird from occupying a space, having means for providing illumination visible to the bird within the space, the illumination repetitively varying in intensity at a rate substantially in the range 30 t 150 Hz. The invention further provides an apparatus for deterring a. bird from occupying a space, having illumination means for providing illumination visible to the bird within the space, the illumination repetitively -varyin the intensity at a rate to be aversive to the bird sufficient to cause the bird to be deterred, and above the critical fusion rate exhibited by humans.

The invention further provides an. apparatus for inducing i a bird aversion to occupying a space, having illumination means for illuminating the space with light repetitively varyin in intensit at a rate effective to induce in the bird aversion to entering the space. The invention further provides an apparatus for deterring a bird from occupying a space, having illumination means for providing illumination to be visible to the bird entering the space, the illumination repetitively varying in intensity at a rate within above the critical flicker fusion rate for humans, and below the critical flicker fusion rate for birds, For example, the lower limit of the range may be 40 or 50 Hz. Preferably the range is 60 to 12 Hz, more preferably 70 to 90 Hz, such as substantially 80 Hz.

The illumination may be provided continuously, or at certain times only, in response to a bird arriving at or near the space, or to protect a space at particular time. Thus, the illumination may be switched on responsive to detection of a bird in the vicinity, or in the spac , such as by use of a motion detector. The illumination ma also be provided at predetennined or random times in an intermittent fashion.

The illumination may be of substantially uniform in spatial distribution, or may vary spatially.

The illumination may vary at. constant frequency, or the frequency may vary periodically or aperiodically. The colour of the illumination may be constant, or it may vary.

The illumination may be such that it is not visible to humans. For example, it may be UV illumination, In a further aspect the invention provides a method for deterring a bird from occupying a space in which illumination is provided visible to the bird within the space, the illumination being U V illumination and varying in intensity at a rate at or below 150 H¾.

In a further aspect the invention provides method for deterring a bird from occupying a space in which illumination is provided visible to the bird within the space, the illumination being UV illumination and varying in intensity at a rate below the critical flicker fusion rate for the bird,

In a further aspect th invention provides apparatus for deterring a bird from occupying a space having means for providing illumination visible to the bird within the space, the illumination not bein visible to humans and varying in intensity at a rate at or below 150 Hz. The illumination may be UY illumination.

In another aspect the invention provides apparatus for deterring a bird from occupying a space havin illumination means for providing illumination visible to the bird within the space, the illumination not being visible to humans and varying in intensity at a rate belo w the critical ilicker fusion rate for the bird. The illumination may be UV illumination.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention is further described by way of example only with reference to the accompanying drawings in which:

Figure 1 is diagrammatic representation of a test method for determining critical flicker fusion frequency in a bird;

Figure 2 is a diagram showing visual image traces representing exemplary electroretinography responses of the pacific black duck; Figure 3 is a diagram showing visual image traces representing exemplary electroretinograph responses of the zebra finch;

Figure 4 is a .diagram showing visual image traces representing exemplary electroretinography response of the corella;

Figure 5 is a diagram showing Figure 5 shows visual image traces representing exemplary electroretinography responses of the budgerigar;

Figure 6 is a diagram showing visual image traces representing exemplary electroretinograph responses of the galah;

Figure 7 is perspective view of apparatu constructed in accordance with the invention;

Figure 8 is a plan view of a body of water with the apparatus of Figure 7 installed adjacent thereto; Figure 9 i s a graphical .representation .of numbers of birds observed on the body of water of Figure 8 during trials;

Figure 10 is a graphical representation of bird arrivals on and departures at and from the body of water of Figure during the- trials, and;

Figure 1 1 is a graphical representation of the numbers of birds present on the bod of water of Figure 9 at various times at each of three phases of the trials. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Figure 1 shows electroretinography ("ERG") apparatus 10 for determining critical flicker fusion ("CCF") frequency in a bird 12, That frequency is the highest frequency of flickering light that is perceived a flickering rather than as continuous light. The apparatus includes a light source 14 coupled to the output of a variable frequency oscillator 16, an electrode 18 placed in external contact with the cornea of the birds eye 20, and a record/display apparatus able to record and visually display electrical signal sensed at the electrode 18. That signal is indicative of the retinal response of the bird's eye to light . The experimental procedure involved illumination at the bird's eye with light from the source 14, that light flickering at a rate dependent on the frequency of sinusoidal signal applied thereto from the oscillator 16, and observation and recordal of the eye' s ERG response as sensed at the electrode 18, This procedure was repeated for a range of flicke frequencies. At low frequencies, the ERG response varies cyclically at the flicker rate, but as the frequenc is increased, a state will be reached where the response will not exhibit such cyclic variation, above the background noise levels, The CCF frequency i the highest frequenc at which ERG response is indicative of flicker perception that is the highest frequencie at which the response .exhibits corresponding cycling variation.

Figures 2 to 6 show exemplary visual image traces obtained by use of the apparatus of Figure 1 with various speeies of bird and various flicker rates indicated at the left of each trace, and over time periods reckoned in milliseconds and indicated along the absciss in each Figure.

Figure 2 shows visual image traces representing exemplary ERG responses of the pacific black duck (Anas s perciUosa) to a green stimulus lamp over a range of flicker rates from 10-140Hz. The lower eight traces shown represent frequencies at which a clear response was observed, indicative dial flicker is perceived. The uppermost 140Hz trace represents the flicker frequency at which the response of the eye did not differ from the background electrical noise. From this, the estimated CFF (eCFF) is within the flicker rate of 130- 140Hz.

Figure 3 shows visual image traces representing exemplar ERG responses of the zebra finch (T ttiopygki guttata) to a green stimulus lamp (peak emission, 457nm)having a flicker rate from i 0- 140Hz . The lower eight traces shown represent frequencies at which a clear response was observed, indicative that flicker was pereeived. The uppermost 140Hz trace represents the flicker frequency at which the response of the eye did not differ from the background electrical noise. The small peaks observed i the trace at 14QHz are produced by the flashing stimulus lamp. From this, the estimated CFF (eCFF) is within the flicker rate of 130-140Hz.

Figure 4 shows visual image traces representing exemplary ERG responses of the corolla (Cacaiua lemdrosms) to a green stimulus lamp having a flicker rate from 10- 170Hz, The lower nine traces shown represent frequencies at which a clear response was observed. The uppermost 170Hz trace represents the flicker frequency at which the response of the eye did not differ from the background electrical noise. From this, the estimated CFF (eCFF) is within the flicker rate of 160-170Hz,

Figure 5 shows visual image traces representing exemplar ERG responses of the budgerigar (Melapsittacus unduiatus) to a green stimulus lamp having a flicker rate from 10-170Hz. The lower sis traces represent frequencies at which a clear response was observed. The uppermost 170Hz trace represents the flicker frequency at which the response of the eye did not differ from the background electrical noise. From this, the estimated CFF (eCFF) is within the flicker rate of 160- 170Hz.

Figure 6 shows visual image traces representing exemplary ERG responses of the galah {Eolophus ros ic piU ) to a green stimulus, lamp (having a flicker rate from 10- 170Hz). The lower nine traces shown represent frequencies at which clear response was observed. The uppermost 170Hz trace represents the flicker frequency at which the response of the eye did not differ from the background electrical noise. From this, the estimated CFF (eCFF) is within the flicker rate of 160-170H¾

The prototype potentially aversive light stimulus (PALS) bird aversion apparatus 50 of Figure 7 is intended for field deployment. It includes an oscilloscope 52, a portable computer 54, and a light source 56 mounted on an adjustable tripod mount 60 allowing variation of the height rotational position and relative tilting of the light source 56. The apparatus also includes a power source 58. These components are portable. Computer 54 controls oscilloscope 52 which in turn supplies electric power to the light source to cause the light source to operate to produce light of character determined by pre-programmed information stored at computer 54, particularly to implement different selectable flicker patterns for the light source 56, in accordance with a predetermined schedule and frequency of flicker. A separate bias control 62 allow the brightness midpoint of the flicker patterns to be adjusted.

The apparatus 50 was used to study the effects of the light stimulus on waterbirds. In thi case, the light source comprised an array of 1024 LEDs emitting white light. Testing was conducted with the apparatu set beside a body of water 64, as shown in Figure 8. Trials were conducted in phases as follows:

* Phase 1 , BEFORE: The light source 56 is placed at the edge of the water body 64 and left off.

* Phase 2, PUR TNG: The light source 56 was switched on,

• Phase 3, AFTER; The light source 56 was switched off, but left by the water body, Coiunts of the number of individual birds present on the water body were taken at the beginning of each phase, then every five minutes for 25 minutes (6 counts per phase). Tests were carried out at night, either during late evening (after 21:00), or early morning (before 06:00), and observations were made using a thermal imaging scope.

When turned on, light from the light source 56 covered the majorit of the water body, the angular extent of the lighting being indicated b "alpha" in Figure 8. A small section of the water body, marked "X", was shaded by an intervening peninsula. The indicated scale represents 30 metres.

Figure 9 indicates the mean number of individual birds counted during each phase of testing. Mean were calculated from the total number of different individuals observed during each phase. Erro bars- represent +/- 1 standard error. From this it is observed that the number of birds present during phase 2 of the tests, durin operation of apparatus 50, was less tha one half the number present during phase 1 of the test, before operation of the apparatus 50. During phase 3 of the tests, after the apparatus 50 was left in position but turned off, the number of birds present increased somewhat but was still less than half the number observed during phase 1 of the tests.

The bar graph of Figure .10 graphically shows the mean numbers of birds arriving and departing the water body during the tests, these being determined for five minute intervals during each phase of operation. The error bars represent +/- 1 standard error. From this it. is observed that, no arrivals or departures arose in phase 1 and in phase 2 of the tests, a significant number of departure occurred in phase 2 and that there were both arrivals and departures durin phase 3. During phase 3, the number of arrivals somewhat exceeded the number of departures, but was substantially less than the number of departures during phase 2. Figure 11 shows the data for number of birds present at each 5 minute observation, during each phase of the tests. From this it is observed that a decrease in bird numbers arose - y - rapidly in rapid response to beginning of operation of the apparatus 50, with, all bird departures occurring within the first 10 minutes, and the majority of departures occurring within the first 5 minutes. The tests above described were made using a sinusoidal flicker waveform. The other waveforms, such as square wave or triangular waveforms may be utilised. The light flashes may be of short duration compared with the duration of intervening periods between flashes. In summary, it is observed that a decrease in the number of birds present occurred during the phase when the apparatus 50 was operated to provide flickering illumination compared to the observations taken before the apparatus 50 is switched on (Figure 9). Furthermore, bird numbers increase again in the 3rd phase when the apparatits 50 was switched off (Figure 9). When observing bird movements, bird departures mainly occurred during the 2nd phase when the apparatus 50 was activated (Figure 10). Bird arrivals on the water body increased following deacti vation of the apparatu 50 (Figure 10).

Additionally, while small numbers of birds remained on the water body during the 2nd phase when the apparatus 50 was on. these individuals were observed retreating into the permanently shaded area shown at "X" in Figure 8.

The described mean were calculated from the total number of individual birds observed at each observation time, for all tests undertaken. Error bars represent ·+■/- 1 standard error. While the invention has been described in the context of its employment to deter birds from occupying space on or around a body of water, it may also, for example, find application:

as a preferably small device in fitted to the front of an aeroplane to possibly provide a clear or clearer approach path for the aeroplane to or from a runway by deterring birds from occupying t he run way in front of the aeroplane; and as a device fitted on or near t wind turbines to deter birds from approaching the turbines.

The invention may be applied to cause a bird or birds to tend to move in single direction, or one of a confined set of directions, away from apparatus of the invenlion or away from a plurality of such apparatuses . For example, bird may be directed to move forwardly of the mouth of a U-shaped array of sources. The array may also be progressivel moved forwardly so as to cause the birds to likewise progressively move forwardly. Again, the apparatus and method of the invention may applied to tend to confine birds to a specific space, by at least partly surrounding the space with light sources in accordance with the invention providing peripheral illumination. These techniques may be of particular application in the case of flightless birds, or birds incapable of flying substantial distances.

The effective range of the apparatus 50 was found to be about 30-50 metre. That is, it was found to provide effective deterrent to birds over that range from the apparatus.

Generally, in accordance with the invention, the lower limit of the range of employable flicker rates is established a being a rate which i close to the critical flicker fusion threshold for humans. That rate may vary with age of the human, secto of the eye that is illuminated, light intensity, wave!ength(s) of the light for example. The publication Landis (1954) Determinants of the Critical Flicker-fusion threshold. Psychological Reviews 24, 259-28.6, describes in more detail the determination of the critical flicker fusion threshold, and the contents of thi are hereb incorporated to form part of the present disclosure. Generally, the critical flicker fusion rate may be as low as 30, 40 or 50 Hz.

Also in accordance with the invention, the upper limit of the range of employable flicker rates is established as being jus below the maximum flicker rate that, can be perceived as non flickering by the bird. Preferably then the flicker rate is in the range of 30 to 150 Hz, with the lower limit of the range being preferably 40 Hz or more preferably 50 Hz. The upper limit may be 150 Hz, or more preferabl 70 to 90 Hz. Thus preferred ranges may preferably be 60 to 120 Hz, more preferably 70 to 9 Hz, such as substantially 80 11/.

In another form of the invention the flickering illumination is provided at one or more wavelengths not visible to humans, but visible to birds. For example, the- illumination may be UV illumination. Where the iUuminatiott is not visible to humans, it may be constant and of any rate below the critical flicke fusion rate for birds. In the above experiments LED peak emission wavelengths used were:

• Red: 635nm

· Green: 509nm

• Blue: 457nm

• UV; 407nm

Also, preferably the UV illumination is in the range of 300-400 nm,

The invention is expected to be of greatest utility as concerns flying birds.

The described construction has been advanced merely by wa of example and man modifications and variations- may be made without departing from the spirit and scope of the invention, which ineludes every novel feature and combinatio of features herein disclosed,

Throughout this specification and the claims which follow, unless the context requires otherwise, the word "comprise", and variations such as "comprises" and "comprising", will be understood to impl the inclusion of a stated intege or step or group of integers or steps but no the exclusion of any other integer or step or group of integers or steps.

The reference in this specification to any prior publication (or information derived from it), or to any matter which is known, is not, and should not be taken as an acknowledgment or admission or any form of suggestion that that prior publication (or information derived from i t) or known matter forms part of the common general knowledge.

Claims

THE CLAIMS DEFINING THE INVENTION ARE AS FOLLOWS:

1. A method for deterring a bird from occupying a space, in which illumination is provided visible to the bird within the space, the illumination repetitively varying in intensity at a rate substantially in the range 30 to 150 Hz.

2. A method for deterring a bird from occupying a space, in which illumination is provided visible to the bird within the space, the illumination repetitively varying the intensity at a rate to be aversive to the bird sufficient to cause the bird t be deterred, and above the critical fusion rate exhibited by humans.

3. A method of protecting a space from a bird, in which illumination is provided, located at or adjacent the space to be observable by the bird, and effective to induce in the bird aversion to entering the space.

4. A method for deterring a. bird from occupying a space, in which illumination i provided visible to the bird entering the space, the illumination repetitively varying in intensit at a rate above the critical flicker fusion rate for humans, and below the critical flicker fusion rate for the bird.

5. A method as claimed in claim 2, claim 3 or claim 4 wherein the illumination repetitively varies in intensity at a rate substantially in the range 30 to 150 Hz.

6. The method of claim 1 o claim 5 wherein the rate is substantiall in the range 40 t 150 Hz.

7. The method of claim 1 or claim 5 wherein the rate is substantially in the range 50 t 150 Hz.

8. The method of claim 7 wherein the rate is substantially in the range 60 to 120 Hz.

9, The method of claim 8 wherein the rate is substantially in the range 70 to 90 Hz

10. The method of claim 9 wherein the rate is substantially 80 Hz

11 . The method of an preceding claim wherein the illumination is provided continuously.

12. The method of any one of claims 1 to 1 1 wherein the illumination is provided intermittently.

13. The method of any one of any preceding claim wherein the illumination is substantially uniform in spatial distribution.

14. The method of any one of claims 1 to 13 wherein the illumination varies spatially.

15. The method of any preceding claim wherein the iliumination periodically varies at constant frequency.

16. The method of any preceding claim wherein the colour of the illumination i constant.

17. The method of any one of claims 1 to 15 wherein the colour of the illumination varies with time.

18. The method of any preceding claim wherein the illumination is provided continuously.

19. The method of any one of claims 1 to 17 wherein the iOumination is provided inteimittently.

20. The method of an preceding claim wherein the illumination is substantially uniform in spatial distribution.

21. The method of any one of claims 1 to 1 wherein the illumination varie spatially.

22. The method of any one of claims 1 to 21 wherein the illumination varies aperiodically.

23. The method of an preceding claim wherein the colou of the illumination i constant.

24. The method of any one of claims 1 to 23 wherein the colour of the illumination varies with time,

25. Apparatus for deterring a bird from occupying a space* having means for providing illumination visible to the bird within the space, the illumination repetiiivel varying in intensity at a rate substantially in the range 30 to 1.50 Hz,

26. Apparatus for deterring a bird from occupying a space, having illumination means for providing illumination visible t the bird within the space, the illumination repetitively

^•varying the intensity at a rate to be aversi.ve to the bird sufficient to cause the bird to be deterred, and above the critical fusion rate .exhibited by humans.

27. Apparatus for inducing in a bird aversion to occupying a space, having illumination means for illuminating the space with light repetitively varying in intensity at a rat effective to induce in the bird aversion to entering the space,.

28. Apparatus for deterring a bird from occupying a space, having illuminatio means for providing illumination to be visible to the bird entering the space, the illumination repetitively varying in intensity at a rate within above the critical flicker fusion rate for humans, and below the critical flicker fusion rate for the bird.

29. Apparatus as claimed in any one of claims 26 to 28 arranged for said repetitively varying in intensity at a rate substantially in the range 30 to 150Hz.

30. The apparatus of claim 25 o claim 29 wherein the rate is substantially .in the range 40 to 150 Hz.

31. The apparatus of claim 30 wherein the rate is substantially in tire range 50 to 150 Hz.

32. The apparatus of claim 31 wherein the rate is substantially in the range 60 to 120 H*.

33. The apparatus of claim 3 wherein the rate is substantially in the range 70 to 90 Hz.

34. The apparatus of claim 33 wherein the rate i s substantially in the range 50 t 80 Hz.

35. The apparatus of any one of claims 25 to 34 arranged for providing said illumination continuously.

36. The apparatus of any one of claims 25 to 35 arranged for providing said illumination intermittently.

37. The apparatus of any one of claims 25 to 36 wherein the illumination is substantially uniform in spatial distribution.

38. The apparatus of any one of claims 25 to 36 wherein the illumination varies spatially.

39. The apparatus of an one of claims 25 to 38 wherein the illumination periodically varies at constant frequency.

40. The apparatus of any one of claims 25 to 38 wherein the illumination varies aperiodic-ally.'

41. The apparatus of any one of claims 25 to 40 wherein the colour of the illumination is of constant.

42. The apparatus of any one of claims 25 to 40 wherein the colour of the illumination varies with time.

43. The method of any one of claims 1 to 24 wherein the illumination is provided to tend to direct the bird to move in at least a confined range of directions.

44. The apparatus of any one of claims 25 to 42, wherein the illumination is provided to tend to direct the bird to move in at least a confined range of directions.

45. The method of any one of claims 1 to 24 and 43, wherein the bird is selected from the group comprising:

pacific black duck;

zebra finch;

corel! a;

budgerigar; and

gala.

46. The apparatus of any one of claims 25 to 42 and 44, ^'wherein, the bird is selected from the group comprising:

pacific black duck;

zebra finch;

corella;

budgerigar; and

47. A method as claimed in claim 1 , 3 or any one of claims 5 to 24, 43 and 45 as directly or indirectly appended to claim 1 or claim 3, wherein the illumination is- not visible to humans .

48. A method as claimed in claim. 47, wherei the illumination i UV illumination.

49. The apparatus of claim 25, claim 27 or any one of claim 28 to 42, 44 or 46, wherein the illumination is not visible to humans,

50. The apparatus of claim 49, wherein the illumination is UV illumination.

51. A method for deterring a bird from occupying a space in which illumination is provided visible to the bird within the space, the illumination being UV illumination and varying, in intensity at a rate at or below 150 Hz.

52. A method for deterrin a bird from occupying a. space in which illumination is provided visible to the bird within the space, the illumination being UV illumination and varying in intensit at a rate below the critical flicker fusion rate for the bird.

53. Apparatus for deterring a bird from occupying a space having mean for providing illumination visible to the bird within the space, the illumination not being visible to humans and varying in intensity at a rate at or below 150 Hz.

54. Apparatus as claimed in claim 53, wherein the illumination is UV illumination.

55. Apparatus for deterring bird from occupying a space having illumination means for providing illumination visible to the bird within the space, the illumination not being visible to humans and varying in intensit at a rate below the critical -flicker fusion rate for the bird.

56. Apparatus as claimed in. claim 55, wherein the illumination is UV illumination.