When old buildings are left in a state of disrepair, wildlife often move in, especially pigeons. Peter Possum has seen vacant houses with broken windows where flocks of pigeons have covered every surface inside the house with droppings, in some places many inches thick.
Why building work creates wildlife problems?
When an old building occupied by wildlife is demolished the animals wait nearby, ready to move back in to the new structure. On the south-side of Brisbane’s CBD there was a shopping centre built many decades ago that had fallen into disrepair. The corrugated sheets on the superstructure were rusted or loose and many entry holes appeared that were very attractive to pigeons. With lack of building maintenance, the pigeons were able to nest inside the structure. Over several decades the flock of pigeons grew and attracted birds from other areas until there was a flock of well over 300 birds.
Recently, it was demolished and immediately, many of the other buildings in the same area had an invasion of pigeons, looking for a new home.
However the rock dove or feral pigeon, is well known for its persistent use of one location and its strong attachment to the place where it was born. Now on the site of the demolished building, a large complex structure is being erected for a brand new shopping complex. So it will be no surprise if the new buildings owners find that lots of pigeons move in on the new structure, since they think of that site as their home base!
The most serious problems occur when there are open air or “alfresco” dining areas and cafes under shade roofs in open courtyards; then the birds have good perches to wait for opportunities to swoop down on “take away” food.
Hopefully the architects of the new building have designed the arches and overhangs in a way that will minimise the opportunities for birds to roost above public areas. If they have used box section beams and arches with clean lines they can minimise the roosting spots. The worst outcome will be where cantilevered arches provide open web trusses and the main beams have a cross section like a capital letter I, because that provides so many places for birds to sit. Installing bird netting or spikes in new buildings becomes an expensive exercise that can be avoided by better design.
So many of our modern buildings may be aesthetically appealing to us but as natural vegetation disappears around our cities, messy birds like pigeons also see our structures as beautiful and very useful alternatives.