Six people replied to my posting of 3 April about feeding bread to ducks and
here is a summary of they, and others, said. There were no citations of
scientific studies on the topic.
1. Educational Value: it helps people to enjoy nature and provides
opportunities to birdos to talk to breados about birds, ecology and bread.
2. Duck Diet: although some bread has a wider range of nutrients, most fed
to ducks is plain white bread, leading to an unbalanced diet including fat
and salt. Can produce obesity (and tameness) leading to difficulty in
escaping predators (and nasty humans). To quote a Braeside Park leaflet
("Don't Feed the Ducks: not all it's quacked up to be"): "When was the last
time you saw a loaf of bread growing in a pond?". Interference with natural
selection.
3. Exotic Waterbirds: mallards etc. love bread and the breados often object to
them being removed, with political consequences.
4. Impact on Fish and Frogs: bread can be a major source of food for carp,
eels and mosquito fish. Carp are believed to cause increased turbidity (less
light for water plants etc.), bank erosion and algal blooms, but again
scientific
evidence is limited (The Age 24.4.99). Mosquito fish are a listed threatening
process (re frogs) in NSW (and other?) legislation.
5. Other Impacts on Wetlands: must affect ecology but impact depends on the
size/nature of the water body and the amount of bread (some people bring
sacks of it). Adverse effects of large numbers of hungry ducks when people
don't feed them. Excess bread a superb culture medium for bacteria and
therefore disease, and encourages rats, silver gulls and introduced birds with
adverse consequences. Phosphate etc. content unlikely to be anything like
large enough to be a major direct cause of increased algal blooms.
6. Conclusions: in some places feeding ducks in moderation may be relatively
innocuous but I'm backing the precautionary principle in relation to smaller
and static water bodies. Notices about bread should explain, not just ban it.
Thanks for their replies to Jenny Adams (especially for her attachment on
feeding birds "Junk Food Kills Birds"), Anthea Fleming, Gloria Glass, Anne
Green, Hugo Phillipps and Philip Veerman. I have a paper copy of the
Braeside Park leaflet if anyone is interested.
Michael Norris
Hampton, Vic.
To unsubscribe from this list, please send a message to
Include ONLY "unsubscribe birding-aus" in the message body (without the
quotes)
|
