Observations · Pest Control

DIY Bird Deterrents

There be Bulbuls (Round 1…)

During the summer growing season we have had some problems with Black-eyed Bulbuls that help themselves to our tomatoes, raspberries and figs. The nasty little buggers always managed to get to the fruits just when they’ve ripened – the cats aren’t doing their jobs of scaring the birds away!

Balckeyed bulbul Pycnonotus tricolor Snowmanradio Derek Keats
Black-Eyed Bulbul – what naughty little birds!
Pycnonotus tricolor
Snowmanradio, Derek Keats
Wikipedia
So with some old CDs and a bit of creative savvy I made a few bird deterrents. Initially I wanted to purchase one of those reflective bird pyramids, but after seeing the price and surviving a minor heart attack – I decided to create my own based on the same principle.
So birds’ visual colour – and light spectrums are different to humans. Humans can see in the 400-750 nm wavelength range (the visual light range, indicated on the figure below). Our range has a normalised bell curve (the purple curve on the left side of the figure below) and our optimum colour range peaks at 555 nm (which is green). Whereas birds have three optimum range peaks, one at green (508 nm), blue (445 nm) and red (565 nm). This makes birds more sensitive to these colours, red being the most prominent. By incorporating red and reflective surfaces into your bird deterrent devices will make your garden a literal eye-sore to birds and they will avoid landing close by.

 

Bird colour vision electromagnetic spectrum vs humans
Bird vision: as compared to human vision.
Top: Electromagnetic spectrum of light (note circle indicates the visible light spectrum); Inductive load & N174, Wikipedia.
Left: Human visual spectrum, with normalised curve superimposed, same axes lables as on right; Vanessaezekowits& BenRG, Wikipedia. 
Right: Bird visual spectrum, L. Shaymal, Wikipedia.

So I took some old scratched up CDs, glued some red and mirror mosaic pieces onto them and voila! It works really well… given the sun is shining. A lot less expensive than the bird pyramids! Hung one close by the chicken coop to scare off would-be pigeon scavengers that eat all the chicken pellets – don’t worry; it is hung at pigeon-eye level, not chicken eye-level, so the chickens are unaffected. The CDs swing around when the wind blows, which scatters light across the garden and helps to fend off fruit thieves.

 

DIY Bird deterrents, front (left) and back (right) hung from tomato stakes. Now the tomatoes and chicken pellets can be spared!

There be Pigeons (Round 2…)

 

Feral pigeon JM Garg wikimedia commons

 

 

Bird control, is similar to pest control, where you want to minimise damaged to your crops preferably through non-harmful and environmentally friendly. You can purchase many of these bird deterrents, but hardly any of them are wallet-friendly. Unfortunately, the DIY CD bird deterrent needs sunlight to work, this means that when it is overcast or raining the pigeon thieves have free range over the chicken pellets and the black-eyed bulbuls perform aerial assaults on the figs and raspberries!!! To my utmost horror!

 

pigeon tpsdave swarm flock
This is basically what it looks like in the chicken coop,
on & in the chicken feeder and on the surrounding walls!!!
When they are disturbed you get this huge ‘fluttering’ noise
and millions of them take to the sky!!!

It is the most terrible thing you ever did witness!!! Pigeon flock photo: tspdave

 

My biggest problem is with the pigeons & chicken pellets, and the bulbuls with the fruits. I find the pigeons to be a bigger nuisance as they can clean out the chicken feeder several times a day leaving none for the chickens – this means the chicken are hungry and I am wasting pellets and money on pigeon thieves! These pigeons, known as city doves or street pigeons, are referred to as ‘feral pigeons’ (Columba livia), which were domesticated from Rock doves. They readily interbreed with other pigeons and have spread across most of the globe. Many people also called them ‘flying rats’ because of their pest value and bird deterrents are constantly implemented in urban – and agricultural settings to scare them away.

 

Columba_livia_pigeon_distribution_map Viktor Kravtchenko Red = native range, pink = intro non-native pop
Geographical distribution of the Feral pigeon,
Columba livia

 

I set out on a few experiments to see whether I can get a back-up deterrent for when the sun don’t shine. I looked up a few alternatives online and found the following candidates:

  • Bird nets, spikes and wires… Now this isn’t going to work, it’s not like I can line the chicken feeder with these and the bird will swoop over them in the garden… I am not fond of netting over plants as this causes damage, such as breaking of branches and fruits (I found this to be very true with frost fleece, especially so when it gets wet!).
  • Sound deterrents, predatory birds and chemicals…Sound deterrents will likely scare the chickens as well, so “No” to that, I don’t want to keep falcons any time soon and chemical are definitely out of the picture!
  • Visual deterrents…So we are back here, other than more reflective devices, I can place stationary figure or outlines of natural predators around the garden and maybe even on the coop roof where the chicken won’t see them… So here are a few things that I tried:

Scarecrow: I made a scarecrow for the chicken coop to warn off would-be thieves, but it is only a temporary scare device as the pigeons become used to it. This means moving it around each day and re-dressing it, which is too much effort. So that idea has been scratched off the list.

 

Sad looking scarecrow
My sad abandoned scarecrow…
probably an example of how not to do a scarecrow…
I think I can hear the pigeons laughing…

 

Rubber snakes: These can be purchased at the toy store. Although, I find that the birds ‘know’ how close they can get to the snakes without being in the hypothetical striking range. I had one on guard at the fig tree, another on the burglar bars at the tomatoes and one on the wall next to the raspberries. The tomatoes where left alone, but the figs and raspberries were still fair game! If I put the snake into the fig tree, they merely eat the figs on the opposite side! So my snake test wasn’t very successful…

 

Bird snake deterrent
My ‘red’ snake…

 

Flapping owl-thing: I found this at local craft market (Garden World). It is a plastic figurine of an owl with big oogly eyes on a pole and flaps its wings when the wind blows. It is marginally effective, because the birds were still picking off the raspberries when I had it about a meter away staring at the raspberries. I put it right in the raspberry pot and that seemed to keep them off of that raspberry plant, but I have three raspberries and only one owl-thing. The cats were convinced that it was edible for a while and I had to show them several times that it is a ‘dead’ figure!

 

Bird owl deterrent
Owl deterrent


Fruit Shield:
This started out as brown paper bags over some of the peaches. The idea was to mask or hide the fruits from the birds, but the paper bags are difficult to secure to the fruits and you can’t readily check up on them to see whether they are good to harvest. Then we decided to cut out pieces of the frost fleece and only cover the raspberries and figs instead of the whole plant (which causes damage). This worked fairly well, as the fleece hid the fruits from preying eyes and even helped them to ripen! The frost fleece lasts about 1-2 months and then completely disintegrates because of the weather exposure, so always keep a pack on hand.

 

The conclusion of the experimentation is that:

  • For sunny days:

Reflective CDs work the best, but only when sunlight hits them. Another bonus is that the CDs keep deterring the birds without any additional input from my side, maybe they need a bit of a fix-up after a year of working in the wind, rain and sun (some tiles fall off and some peel their shiny stuff). They work for both the vegetable garden and chicken coop!

I have seen many versions of the reflective visual deterrents, such as red reflective tape, iridescent hanging ornaments, pieces of strung up foil and even blown-up wine bladders!

 

  • Cloudy/rainy days:

Cover fruits with cut-out pieces of frost fleece to protect them when it is cloudy or raining. They will need to be replaced once a month if cloudy weather persists due to disintegration. Again these don’t need extra input after installation and they allow easy access to check on ripening fruits. It can easily be applied to fruit clusters (raspberry) or a few individual fruits like the figs/peaches, but it might be a mission to cover and check each and every tomato!

All in all, the fruit shields worked well for keeping the birds away from the raspberries and the figs, but I still haven’t found a cloudy-day deterrent for the chicken coop… I will try a few more ideas throughout the year and report again on what I have found.

 

Pigeon trap column
Large Pigeon Trap
LOL!
Won’t it be funny if I put one of these
badboys in the garden!! I just don’t know
what you would do with them all once you
caught them…

 

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