Name: Janet C.
We have two swans on a small lake by our house. They
will make noise, like a loud trumpeting sound,while making their necks
go up and down. Why do they do this? Sometimes they flap their wings
and almost run on the water. What is the significance of this? They
actually killed two geese in the lake by holding them underwater. Is
this usual behavior? I have read some of the articles and they don't
mention this behavior. Thanks
Trumpeting and neck bobbing are displays, part of establishment of territory
and courtship. "running" over the water might be an aggressive display to
other birds, especially geese. Swans are usually very aggressive toward
geese and are often kept in corporate park and golf course lakes to help
drive away geese.
Most birds use a series of behaviors to reinforce the bond between the mated
pair. In the spring before the nesting, these behaviors is most apparent
for this is the signals that the species use to prepare and execute the
mating process, and all through the time that the young are being attended
these behaviors will continue to lesser degree. What you observed is
typical swan behavior.
Both Canada Geese and Trumpeter Swans are aggressive species. Very
aggressive, even toward humans. They will not tolerate competition in their
nesting area. Swans being larger will have the upper hand and I am not
surprised that the Geese were injured or killed. The Geese were nesting
within the swan's territory I presume. I have not seen or heard of Geese
being killed, usually they just leave when challenged, but I am not
surprised due to their aggressive behavior.
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Update: June 2012