Many people enjoy birds, especially watching song birds and other species in backyards and gardens, not to mention, the variety found in parks and forests around Winnipeg and throughout Manitoba. Wild birds are one of the most vulnerable populations of wildlife to human threats. Although most birds in Canada are protected through conservation acts, in particular, the Migratory Bird Conventions Act and the Species at Risk Act, there are still many threats to birds, especially in urban areas. Unsurprising, many of these threats are due to human influence, although often indirectly.
By far, the most common killer of birds throughout Canada are cats, both domestic and feral. Cats alone kill more birds than the other top ten threats combined and although the majority of the kills come from feral cats, domestic cats are also a danger and the City of Winnipeg requires cats to be kept inside. However, in rural areas, cats are commonly outside and if a cat is becoming a bird hunter, a bell can be a helpful warning for birds.
Another leading cause of death to birds is collision with human structures. Although many people, particularly those opposed to wind energy, blame wind turbines for large number of bird deaths, but the numbers so far are actually quite low, only in the 10s of thousands nationally. The most common danger are power lines collisions and electrocutions, but house and buildings are also a danger. Nuthatches, chickadees, and pigeons are more likely to be killed by striking houses and buildings. Turning off lights, especially in large municipal buildings helps, as birds are attracted to the lights, and also finding methods to make windows less reflective or transparent to minimize confusion.
Communication towers are another danger, especially for nocturnal migrating birds. A study from the University of Southern California found that 97% of birds killed by communication towers are songbirds, and species affected in Canada include kinglets and warblers. Birds are attracted to the tower lights, especially in bad weather if other navigational cues are unavailable. Researchers suggest that simply changing the tower lights from a steady beam to a blinking light could reduce deaths by up to 50%.
Sadly, another all too common cause of death for birds is collision with a vehicle. A surprising variety of birds are at risk to collision from cars and trucks, as they can be hit simply flying in midair or from crossing the road. Another risk is for birds that are hunting or searching for food along roadways that get hit by passing vehicles. Just recently in Idaho, dozens of owls have been found along the interstate. Experts speculate that the owls were probably hungry and hunting for mice along the highway and were hit by vehicles.
Other leading threats to birds are due to commercial industries, such as agricultural pesticides and forestry. Forestry in particular can have long term consequences, as entire habitats are altered, which impacts breeding especially, as nests and eggs are destroyed. Another large scale problem that can be both commercial and residential is agricultural mowing, which in particular threatens young birds in nests. One example of a local species impacted by mowing is the bobolink, which is a protected birds that nests in grasses. In Canada alone, millions of bobolinks are killed by cutting and clearing grasses, most commonly for agriculture.
Awareness of some of the threats that birds are currently facing is the first step in considering further ways to mitigate those threats. It is important to remember the role that we play and our impact on the wildlife around us, particularly threatened species, such as songbirds. Small changes to behavior, from keeping our cats indoors or at least alerting birds to the approaching threat, to reducing lights in urban buildings or changing the lights on communication towers could have a big impact.
*Article originally printed in Prairie Wildlife Rehabilitation Centre newsletter.
For more information or to become a member and subscribe to the newsletter, please visit the PWRC website: http://pwildlife.ca/.