Sid Buckwold Bridge Rehabilitation

Pigeons had infested Sid Buckwold Bridge over the past five decades. The build-up of pigeon poop underneath the bridge added nearly 619,430kg of weight to the bridge (equivalent to 356 medium sized vehicles), potentially compromising the structure of the bridge and damaging concrete. 

In order to successfully rehabilitate the Sid Buckwold Bridge, it was necessary to reduce the flock and the build-up of pigeon poop in 36 cavities. These cavities are part of the bridge design, however they had created secluded areas for pigeons to breed and thrive. Approximately 2,300 pigeons were removed.

Through the bridge rehabilitation contract, a specialized pest control company was hired for the flock reduction program to trap and humanely euthanize the pigeons and clean the bridge structure.  

The City considered a variety of options to control the pigeons. However, with the large pigeon population, large area, multiple cavities beneath the bridge deck and the probability of just displacing or moving the flock to nearby homes or other facilities, it was recommended the best action for the rehabilitation is to complete the flock reduction program and clean out the cavities.  

Now that the program and cleaning is complete, barriers/fencing has been installed in the cavities and other areas of the bridge most susceptible to pigeon roosting. It is hoped this will stop damage to the structure and reduce the flock by 50-70%, ensuring the investment made in the bridge rehabilitation will last. There were three phases to the work: trapping and removing the pigeons, cleaning up the pigeon poop and building the barriers/fencing. The total cost of the work, which is part of the bridge rehabilitation budget, is $800,000.   

In addition to the serious structural damage pigeons cause, pigeon droppings may pose a health hazard to the general public, our staff and our contractors.  All City departments and contractors abide by best practices and ethical strategies to control problem animal populations.   

How do you know there were approximately 2,300 pigeons infesting the bridge that were removed? 

The original estimate was 1,500 but during the flock reduction program, it was determined there were actually approximately 2,300 infesting the structure. 

How did you determine that the accumulation of pigeon poop is 619,430 kg? 

The Sid Buckwold Bridge has a total of 36 areas (cavities) where pigeons are roosting. The pigeon poop accumulation was physically measured in 3 of the bridge cavities, which allowed for a prediction of the total mass of poop. 

Can you explain why pigeon poop compromises the structure of the bridge? 

Bridges are designed to accommodate dead load (weight of the bridge) and live load (vehicles/people) without a lot of additional load carrying capacity. In the inspection of the bridge it was confirmed that the bridge was at the limit for load carrying capacity; therefore, it was critical to have the additional weight from the pigeon poop removed.   

In addition, pigeon poop is acidic and known to damage concrete and corrode steel. The poop was located near critical concrete and steel components of the bridge, which if not dealt with, would have posed a risk to bridge failure.  

Why wasn’t a cleaning or pigeon control done before? 

This area is inaccessible by normal means. The 36 cavities, which are part of the bridge design, are underneath the bridge deck which is above the river. The bridge was designed and built (in the mid-1960s) without a way for people to easily access the 36 spaces under the bridge deck. The best time for the City to have the work done was during the rehabilitation work. Scaffolding and the proper safety structures were put in place so workers could access these areas. It was efficient and cost-effective.   

What did the clean-up process entail? 

The contractor was responsible for the removal of the pigeon poop. The removal was done by either bagging, dry vacuuming or wet vacuuming the poop and then disposing of it at either the landfill or waste water treatment plant as appropriate.  

How did the contractor ensure the poop didn’t go into the water?  

The poop was collected and disposed of at the appropriate sites. The contract did not allow for the dumping of any material, construction related or pigeon poop into the water. Inspection staff were present during the removal operation to ensure the approved methods were followed.  

Had alternatives to euthanizing been considered? 

In the years leading up to this project the City considered a variety of options to control the pigeons. Other methods, such as a falcon with a falconer, have been successful at locations where the flock is not of this scale.  

With a flock of approximately 2,300 pigeons, the best action was to reduce the flock by trapping and humanely euthanizing them. Following that, the bridge was cleaned and barriers/fencing were installed to help prevent further accumulation of pigeons.  

With such a large flock, it was necessary to ensure the pigeon infestation was not relocated to nearby homes or other facilities. Like many birds, pigeons have a homing instinct and most return to their original space, so even if there are barriers are in place, the flock would be displaced to the surrounding neighbourhoods where it would similarly compromise structures.  

What does humanely euthanize mean? 

The work was contracted to animal control experts. The City didn’t perform this job.  It’s the City’s understanding that any such contractor abides by the Canadian Veterinary Medical Association (CVMA) position on euthanasia:  

• The CVMA holds that when animals are euthanized, death must be quick using a method that causes the least possible pain and distress. The most appropriate method of euthanasia may vary depending on animal species, age, weight, temperament, and health status. 

Incidentally, the CVMA also has a position on pest control which is guided by the Canadian Pest Control Product Act. The position is: 

• The CMVA recognizes that lethal and non-lethal pest control measures may need to be used against nuisance animals to reduce damage or conflict, promote sustainable agricultural production, control diseases, and/or to ensure the conservation of biodiversity. Such measures should be humane, scientifically based, have minimal environmental or human health impacts, and abide by local legislative and municipal requirements.   

The Act defines “pest” as “an animal, a plant or other organism that is injurious, noxious or troublesome, whether directly or indirectly, and an injurious, noxious or troublesome condition or organic function of an animal, a plant or other organism.” 

Would any deterrents like repellents, netting or plastic owls work, so the accumulation of pigeons over the years is slower? 

Yes. Now that the flock has been reduced and the bridge cleaned, barriers/fencing have been installed to prevent pigeons from roosting within the bridge cavities again. We will continue to explore methods such as using a falcon or using sounds to deter pigeons from the bridge.  

Prior to this program, when was the last time any clean-up of pigeon poop occurred on the Sid Buckwold Bridge? 

During the construction of the Rotary Park lift station in 2011, a pipeline for wastewater was installed across the bridge in the abutments at each end. To allow for the installation, the City had to clean out the abutments at each side. The removal of the poop and cleaning cost approximately $100,000.  

Can pigeon poop be composted?  

No. Current composting operations would not be able to accommodate this material.