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Swans and Cygnets
Name: Vida
Location: N/A
Country: N/A
Date: N/A
Question:
I live near a 17 acre lake. We had a pair of nesting
mutes which had successfully raised 6 surviving cygnets each summer for
three summers.
This year, two trumpeters flew in and the mute male fought them to the
death. His efforts were complicated by the fact that wire had been placed
in the water to keep the geese and ducks from walking onto the shore. The
mute male died from his attack of the trumpeter and being tangled in the
wire.
The female mute remained on her nest and successfully hatched 7 cygnets!
We were all so happy to see her doing such a great job!
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The cygnets are not quite full grown now. They are still dark grey and
their wings are still small. For some reason,
the mother has begun 'rejecting' one of the cygnets. She has gone so far
a crying cygnet into the weeds away from the other 6. She had been
raising the 7 toghether all along and I don't have any
idea why she would 'turn' on this one.
Her attack on it this morning was quite violent. It must have returned to
the group during the night. At day light, she drove it away
by trying to drown it with her head, and then with her body. It scrambled
onto shore and tried to escape her.
Do you have any idea why she might do this? I'm thinking perhaps she
thinks she should only have 6? She is alone
raising them, perhaps he wasn't 'behaving'. Or, perhaps it's too small
help this poor cygnet.
Replies:
I have been trying for some days to figure out how to respond to this
message. First of all, it is almost certain that the mute swan did NOT die
from fighting the trumpeter, such fights are almost never fatal. Wire in the
water? That seems an incredible hazard for all birds and wildlife; without
knowing details it seems that would be a much more likely cause of death.
As for the aggression of female to young, I haven't found any references
yet that help. It is most unlikely the adult can count; there is very little
evidence that birds have that capacity, certainly not swans. I really can't
think of any reason she would turn on one cygnet. Sometimes parents abandon
young that can't keep up, etc. but there really wouldn't be any reason to
attack. Are you quite sure this is one of her cygnets?
One of the problems I've had responding is my bias - as a naturalist I
would favor a native trumpeter swan over a non-native mute any day. The
whole situation: an ecosystem with a high level of human disturbance and
modification, and non-native species, makes me a bit sad: where can the
trumpeter swans go in such a system?
But I'm sorry I can't answer the question. If I find out anything else I
will send it along.
John Elliott
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Update: June 2012
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