Understanding Human-related Causes of Bird Mortalities

Female cardinal and male cardinal on a post

What are the Major Causes of Bird Mortalities?

A significant number of birds and other wildlife are killed by direct human-caused factors, such as collisions with structures and vehicles, predation by free-ranging cats, and other threats.

A study conducted by the LossLab analyzed the estimated mortality of wild bird populations from various human-related causes in both Canada and the United States (US). Please see results below:

Graph displaying the estimated mortality rates for wild birds from various human-related causes such as cats and building windows for both Canada and the US, as summarized below


As detailed above, cats are the leading cause of bird mortality in both Canada and the US. This is closely followed by building windows and automobiles. Adding bird friendly stickers on window panes and keeping household cats leashed when outdoors are great ways to protect our native bird populations.

It is important to stay mindful of the impact our actions have on our native bird populations. Ensuring adequate habitats, resources and protection to support these populations will help ensure the long-term survival of many of our native bird populations, such as the Northern Cardinal and the Blue Jay.

Infographic from Smithsonian outlining bird mortality rates, the causes and ways to reduce them, as summarized below

Habitat loss has a major impact on native bird populations. Ensuring adequate habitats for these species will help keep populations at healthy levels. Additionally, limiting the use of pesticides in agricultural and residential use will help reduce the number of birds killed per year due to broadcasting spraying. It is currently estimated that 2.7 million birds are killed per year due to pesticide usage. Reducing night lighting will additionally help protect these native populations from building collisions.