Ducks, geese, and swans are very
popular with urban park goers. According to the 2006 National
Survey of Fishing, Hunting, and Wildlife Associated Recreation, more
people travel away from home to watch waterfowl than any other type of
birds. Of the 20 million Americans over age 16 who travel to see birds,
15.4 million travel to see waterfowl. A lot of that travel is probably to
feed ducks at a local park. Kids love feeding ducks and geese. It’s
an urban and suburban American tradition, and probably one of the biggest ways
that people become interested in birds!
On the other hand, there are
some significant potential problems with encouraging duck feeding
Pollution and Water Quality—Especially on smaller ponds or
lakes, increasing the amount of ducks and duck droppings in the water can lead to
heavy loads of nitrates and other nutrients in the water, leading to
eutrophication or other water quality problems. (See
abstract of one study here.)
Diseases—Waterfowl congregations are
breeding grounds for botulism and potentially avian influenza. Again,
especially in confined areas—small ponds, patches of open water in a frozen
lake, etc these diseases are more easily spread. According to one
online source “In 1993, Muscovy
ducks, released into the canals in Venice, California, tested positive for duck
plague, duck virus enteritis (DVE), a fatal herpes virus spread through [their
droppings]. Ducks and geese on the canals began to have violent seizures and
then died.” While
there is only a tiny chance that this could involve transmission of disease to humans, it is
always a possibility—especially where congregations of geese or ducks leave droppings
on footpaths or other areas where people are walking. (See abstracts of two
studies on urban duck diseases here
and here.)
Genetic
mixing—We’ve all
seen Frankenducks out there—birds that are obviously strange domestic Mallard
strains or even hybrids between these birds and other domesticated or wild
ducks. Some ducks, such as American Black Ducks are especially
susceptible to mixing with other ducks, so the fewer domestic ducks out there,
the better. Even creating areas where large numbers of Mallards and
American Black Ducks mix may help facilitating pair bonding between mismatched
birds. (More on Mallard-Black Duck relationships in two studies here
and here.)
Duck
nutrition—That old
bread that most people take down to the local pond to feed to the ducks has
limited nutritional value, and is going to go straight through many of the
ducks and become almost instant water pollution. A commercially available
duck food might be a better option, but that still doesn’t address the other issues. (See a study of duck food
nutrition online
here.
Legal
issues—many places have already outlawed
feeding of wild or domestic duck flocks. Check with local authorities
before even thinking about encouraging others to feed ducks.
So do the risks outweigh the
benefits of feeding or encouraging the establishment of a park duck
flock? While this is ultimately a local decision for each municipality or
other governing body, these issues listed here are among the most important to
consider when making that decision.
(Domestic duck image (c) Lynne Marsho)
If you are working on a green buildiing project, or want to encourage your local municipality to adopt birdsafe building standards, take a look at some innovative birdsafe design guidelines out of Toronto and New York City.
Toronto Bird-Friendly Development Guidelines (warning: very large pdf file)
46 pages of great information on how to design buildings so that birds won't crash into them while migrating at night or moving about during the daytime.
Toronto Bird-Friendly Development Rating System and Acknowledgement Program
Toronto has a three-tiered system that requires new buildings to meet a minimum standard of birdsafe design, but encourages developers to strive for a Preferred or even Excellent rating.
New York City Audubon's Bird-Safe Building Guidelines (warning: another very large pdf file)
A 59 page treasure-trove of architectural guidelines and examples showing how to keep birds safe.