Killing with kindness: birdfeeder associated diseases in wild birds
Birding is the one of the leading recreational past times in the United States. In addition to the popularity of bird viewing and species identification, millions of people actively and purposefully attract wild birds to their homes and yards with bird feeders. Commonly encountered species at bird feeders are primarily passerines, and those that are resident in an area may use feeders year- round, especially in winter when weather is harsh and other sources of food are difficult to access. Types of feeders vary from the common tube-shaped seed or nectar feeders, to platform-type structures that hang or sit on a post or on the ground. Feeders are stocked with sunflower seeds, millet, cracked corn, thistle, peanuts, sugar solution, or suet.
Bird feeders can be an important source of nutrition for birds, especially during abnormal or harsh climate or foraging conditions, yet they are man-made constructs and therefore an artificial habitat, promoting repeated congregation of multiple species of birds around a point source of food. Not only may this result in unnatural densities of birds at a given point in time, it can also lead to interactions among and between species that would normally not occur.
PREVENTING DISEASE TRANSMISSION AT BIRD FEEDERS
Keeping bird feeders clean and using fresh food, unused portions of which are changed out regularly, are keys to preventing disease transmission at bird feeders. Feeders should be cleaned at least once a week with 10% bleach solutions. The ground under and around feeders should be swept to remove droppings and unused feed. Water in drinkers or baths should be changed daily.
The type of feeder used has implications for disease transmission as well. Tube feeders that do not accumulate bird droppings the way that platform feeders do may be beneficial in this regard, although studies have shown that tube feeders promote direct contact between birds competing for the limited access points.
To prevent zoonotic potential, people should wear rubber gloves when cleaning. Keeping cats indoors during feeder-associated outbreaks is important for the health of the cats and their owners. During outbreaks of mycoplasmosis or salmonellosis, people should be urged to stop using bird feeders until the epidemic resolves.
Download the complete PDF from which these excertps were taken.
Kirsten V.K. Gilardi, DVM, DACZM School of Veterinary Medicine University of California, Davis, CA
