Ability to Respond Total:15 / 25Ability to Respond = ( Ease of Response + Tools in Place )
Confidence:High
Confidence Notes:
Impact
Spread
Notes
Score
Spread Rate
Mute swans are native to northern and central Eurasia and have been domesticated in Western Europe since the 12th century. Mute swans were introduced to the eastern United States from Western Europe during the late 1800s and have spread across the USA.
5
Spread Amount
Can occupy many CA watershed habitats (city parks, lakes, delta, ponds, estuaries).
4
Damage
Notes
Score
Ecological
Can aggressively displace native waterfowl species and, once established, can severely damage wetlands by consuming large amounts of submerged aquatic vegetation that other species depend on for food and shelter.
4
Agricultural
Will frequent agricultural crops if other food sources are limited. Mute swans may serve as a vector or reservoirs for diseases of agricultural significance including avian influenza and Newcastle disease viruses.
1
Infrastructure
0
Cultural
Potential to displace many species of cultural importance due to their damage to habitats and direct aggressiveness to other waterfowl. They are also considered a nuisance in some areas due to their abundant fecal droppings.
1
Health
Can alter water quality by disturbing sediment during feeding and by fouling water. Are they are so aggressive that they may attack humans/pets during their breeding season. They also have potential to transmit salmonellosis, swimmer's itch, and E. coli.
1
Benefit
Notes
Score
Ecological
0
Agricultural
0
Infrastructure
0
Cultural
Some people like these birds for asthetic reasons.
1
Health
0
Total
15
Ability to Respond
Ease of Response
Notes
Score
Detection
Easily seen due to striking white coloration and size. Juveniles could be mistaken for other native swan species, but the yellow bill of adults makes them easily recognizable.
5
Control
Some difficulty due to politically limited control measures and negative public sentiment to control.
3
Tools in Place
Notes
Score
Entry
Prohibitions are publicized and enforced by CDFG.
3
Control
Hazing using audio pyrotechnics and other visual deterrents can be successful at reducing local Mute swan abundance. The use of dogs to chase birds and exclusionary fencing to limit their access to habitat or removing available habitat can be successful.
