As Trumpeters return to long-vacant habitats, they often encounter conditions dramatically altered by human activities. They are often particularly vulnerable while they are learning to use a new area. Some of the threats they now face include:
- Loss of knowledge of traditional migration routes to more southerly wintering areas.
- New diseases, such as avian influenza, with potentially devastating consequences.
- Loss of wetlands and diminished quality.
- Loss of farm lands where crop residues have been providing important winter food resources.
- Fatal lead shot poisoning when swans swallow pellets found in soil where shooting activities have occurred
- Illegal shooting
- Climate change that is reducing breeding habitat quality in the relatively arid western US
- Powerline collisions that injure or kill swans.
- Human disturbance that disrupts nesting attempts or flushes wintering swans and makes them burn up needed energy reserves.
- Lack of funding to provide long-term habitat protection.
