Tundra Swan Family Defense

[Norm Dulak]

In the past, I posted a link to a YouTube video clip of mine on another BPN forum, in which the parents of a family of six tundra (aka whistling) swans acted to drive away other swans. I hoped others would find the clip interesting.

Now, I'd like to offer the link again here with a request that you please give me your views of what you think the action shown means, both from the perspective of the tundra swan family, and from that of the other two swans. The link to my video clip is: http://www.youtube.com/user/ncdulak11.

While I think the family defense is understandable, why do you think the approaching pair paddled directly toward the family?

Norm

[John Chardine]

Hard to say Norm without having the birds banded and known (sex, pair status, age etc). There are examples of young birds in pairs or singly, associating with breeding birds, attempting to adopt young, killing young to take over the nest and other contexts. But these usually occur on the breeding grounds, which as you know for Tundra Swans is the high Arctic. However, it's still possible that the approaching pair was newly formed and of young birds, somehow attracted to the family. Note that one of the approaching birds was "allowed" to stay near the family at the end of the altercation. Also at about 8s into the movie something dark jumps out of the water right in the middle of the fracas. Do you know what it is? It looks like up to three smaller diving ducks to me but I can't see clearly enough in the video.

[Norm Dulak]

Hard to say Norm without having the birds banded and known (sex, pair status, age etc). There are examples of young birds in pairs or singly, associating with breeding birds, attempting to adopt young, killing young to take over the nest and other contexts. But these usually occur on the breeding grounds, which as you know for Tundra Swans is the high Arctic. However, it's still possible that the approaching pair was newly formed and of young birds, somehow attracted to the family. Note that one of the approaching birds was "allowed" to stay near the family at the end of the altercation. Also at about 8s into the movie something dark jumps out of the water right in the middle of the fracas. Do you know what it is? It looks like up to three smaller diving ducks to me but I can't see clearly enough in the video.

Thanks, John, for your most interesting comments.

I agree with you that it's difficult to understand what is happening here, since the family is so far beyond the breeding ground and we don't know the sex and age of the two approaching swans.

But isn't what happened here fascinating? And isn't it interesting what even crude video like mine can reveal about bird behavior?

My fascination with birds has always been based not only on their marvelous morphological differences, but on their behavioral diversity as well. And I think that video can best capture the latter. I hope others will be encouraged to turn their cameras on in video mode more often, if they have the capability.

It is indeed interesting that one member of the approaching pair was allowed to remain in the vicinity of the family. Does that suggest to you that that bird might have been perceived by the parents to be a non-threatening female, although there is (to me) no apparent morphological marker that distinguishes male swans from female swans? Are there swan pheromones?

Finally, I never noticed the dark object(s) at about 8 seconds into the clip before. I've tried to step the video past that point slowly but have learned nothing. I have absolutely no idea of what that could be (shades of the loch ness monster )!

Norm

[Jeff Cashdollar]

Interesting video - looks like territorial behavior to me - what is that dark 8s animal (turtle, snake frog,,??)

[Norm Dulak]

Hi everyone. I think I've solved the mystery of the dark object that appears around 8 seconds into the video clip. But to understand it, you need some background on our creek.

By our home, Fairlee Creek is a very shallow, muddy-bottomed body of water that each summer becomes filled with a thick growth of Lotus plants. The growth of those plants becomes so thick that it is almost impossible to punch through them in a kayak. In the fall the Lotus plants begin to degrade, eventually sinking beneath the surface of the water. The swans love the plant residues, and continually "tipple" to reach them on the bottom of the shallow creek.

To determine what the dark object was, I opened the video clip in iMovie, where I was able to work through the frames very precisely until I found the object. I then made a screen shot of that frame, converted to JPEG, and optimized in PS CS5 for the web. The result is attached.

Based upon the isolated image, my knowledge of the creek and the vegetation in it, and the action of the swans, I've concluded that the dark object is most likely a bolus of lotus residue and mud, rendered animated by the violent thrashing and leg kicking of the adjacent tundra swan.

Norm