Bird deterrents are big business. There’s many a building or inner city area spoiled by the detritus that pigeons and such leave behind. In fact pigeons are probably the biggest culprit, closely followed by seagulls in coastal areas.

And the thing is, deterring birds from nesting, roosting and generally being sociable on your rooftops and parapets is actually very easy to avoid and humane in practice.

I remember looking into this and came across the phrase ‘bird spikes’ and felt a little alarmed. I had images of hapless pigeons being impaled upon metal barbs, cooing their dying breath feebly to their pigeon pals. Funny thing is, nothing could be further from the truth.

Next time you’re walking around your local town/city looking up at the buildings around you. Chances are you’ll see some spiky looking contraptions – and no pigeons. That’s because what you’re looking at are bird deterrents.

Same on motorways. They tend to be on top of surveillance cameras and such. Little rows of slim spikes sat atop Big Brothers' eyes … Actually, I think the bird deterrents are a bit reminiscent of my Grans’ crochet needles, attached to base but maybe I’ve just go too much time on my hands.

Bird deterrents are actually made from various different materials, are easy to install (providing you’re ok with heights!) and are only designed to deter the birds from roosting – not, as I thought, as a means of a cruel and painful death.

You only have to think of somewhere like Trafalgar Square in London and you probably think of nelsons’ Column first, closely followed by an image of thousands of pigeons and the crap (no pun intended) that they leave behind.

The bird spikes are deemed safe – due to their design – by bird cruelty charities (RSPB in the UK for e.g.) and are largely employed by businesses and owners of apartments buildings, local councils and so on.

Having seen them put to work in and around Lisbon (now I realise what they are) I can testify to the fact that they do indeed prevent pigeons from roosting and go a long way towards keeping public areas and buildings remarkably free of bird mess.

Apparently they are one of the most effective ways to deter roosting birds (alongside bird netting) and, judging on the prices of the ready-to-install bird spikes that I’ve seen, you’ll hardly require a degree in engineering to A) be able to install them and B) understand how they work and why they’re so affective.

All you do is purchase the type and size of bird deterrents that are the most suitable for your purpose – e.g. window ledge, drainage pipes, and then simply glue them into position. And hey presto pigeons/birds homing in to roost take a quick look and decide to take themselves – and their mess – elsewhere.

You could say that it’s your gain and someone else’s mess!