When oil sticks to a bird's feathers, it causes them to mat and separate, impairing waterproofing and exposing the animal's sensitive skin to extremes in temperature. This can result in hypothermia, meaning the bird becomes cold, or hyperthermia, which results in overheating.
Collisions. Window strikes – estimated to kill 97 to 976 million birds/year – Millions of houses and buildings, with their billions of windows, pose a significant threat to birds. Birds see the natural habitat mirrored in the glass and fly directly into the window, causing injury and, in 50% or more of the cases, death ...
Top Threats to Birds (U.S. only. Ordered by Median Estimate of Bird Mortality Annually. As of 2017.)
|Hazard/Type||Min Range||Median/Avg. Estimated|
|Cats Loss et al. 2013a||1,400,000,000||2,400,000,000|
|Oil Pits Trail 2006||500,000||750,000|
Lethargy. A sick and dying bird will show minimal movement and may also be very still with their eyes closed and a hunched-over position. Birds that may not normally be welcoming to handling may allow you to pick them up, as they're too weak to fly off or move away from you.