{"id":156408,"date":"2024-04-02T05:20:06","date_gmt":"2024-04-02T11:20:06","guid":{"rendered":"https:\/\/www.featheredphotography.com\/blog\/?p=156408"},"modified":"2024-04-02T05:25:28","modified_gmt":"2024-04-02T11:25:28","slug":"western-grebes-an-optical-illusion-and-an-unusual-behavior","status":"publish","type":"post","link":"https:\/\/featheredphotography.com\/blog\/2024\/04\/02\/western-grebes-an-optical-illusion-and-an-unusual-behavior\/","title":{"rendered":"Western Grebes, An Optical Illusion And An Unusual Behavior"},"content":{"rendered":"

Occasionally I rerun a favorite older post. This one was published nearly eight years ago, in August of 2016. For this version I’ve edited the text, tweaked the formatting and changed the title.<\/em><\/p>\n

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\"western<\/p>\n

1\/2000, f\/6.3, ISO 400, Canon 7D,<\/em> Canon EF 500mm f\/4L IS II USM + 1.4 tc,\u00a0not baited, set up or called in<\/p>\n

First, the optical illusion. These are both Western Grebes. The bird with the bright red eye is an adult parent of the juvenile with the grayish head. The younger bird is almost full-grown and just about the same size as its parent.<\/p>\n

Please study the image for a few moments and decide what you’re seeing. Or what you think you’re seeing.<\/p>\n

When I first saw this photo on my computer screen, my brain decided that the adult has its back to the viewer and is swimming away from us and directly into the outstretched neck of the juvenile, whose body we see lengthwise in the water. It wasn’t until I studied the rest of the series that I realized that I had it bass-ackward.<\/p>\n

Following are photos that were taken before this one, and after.<\/p>\n

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\"western<\/p>\n

1\/2000, f\/6.3, ISO 400, Canon 7D,<\/em> Canon EF 500mm f\/4L IS II USM + 1.4 tc,\u00a0not baited, set up or called in<\/p>\n

A few seconds earlier the juvenile swam up to the adult…<\/p>\n

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\"western<\/p>\n

1\/2000, f\/6.3, ISO 400, Canon 7D,<\/em> Canon EF 500mm f\/4L IS II USM + 1.4 tc,\u00a0not baited, set up or called in<\/p>\n

and began to slide its head over the crook of the neck of its parent.<\/p>\n

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\"western<\/p>\n

1\/2000, f\/6.3, ISO 400, Canon 7D,<\/em> Canon EF 500mm f\/4L IS II USM + 1.4 tc,\u00a0not baited, set up or called in<\/p>\n

As both birds turned to my right in the water, the youngster continued to swim forward…<\/p>\n

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\"western<\/p>\n

1\/2000, f\/6.3, ISO 400, Canon 7D,<\/em> Canon EF 500mm f\/4L IS II USM + 1.4 tc,\u00a0not baited, set up or called in<\/p>\n

and bend its long neck to the right, which wrapped its neck around the base of the adult’s neck.<\/p>\n

This is the image I presented first. Now it should be clear that what I thought I saw in the first image was really an illusion. The body to the left actually belongs to the red-eyed adult and not to the juvenile.<\/p>\n

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\"western<\/p>\n

1\/2000, f\/6.3, ISO 400, Canon 7D,<\/em> Canon EF 500mm f\/4L IS II USM + 1.4 tc,\u00a0not baited, set up or called in<\/p>\n

As the juvenile continued to push forward, its body began to slither over the top of the lower neck of the adult.<\/p>\n

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\"western<\/p>\n

1\/2000, f\/6.3, ISO 400, Canon 7D,<\/em> Canon EF 500mm f\/4L IS II USM + 1.4 tc,\u00a0not baited, set up or called in<\/p>\n

The youngster appeared to deliberately attempt to place its body lengthwise on top of its parent.<\/p>\n

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\"western<\/p>\n

1\/2000, f\/6.3, ISO 400, Canon 7D,<\/em> Canon EF 500mm f\/4L IS II USM + 1.4 tc,\u00a0not baited, set up or called in<\/p>\n

The weight of the very large young bird forced the adult underwater, except for its head and neck. What appears to be the body of the adult is really that of the juvenile.<\/p>\n

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\"western<\/p>\n

1\/2000, f\/6.3, ISO 400, Canon 7D,<\/em> Canon EF 500mm f\/4L IS II USM + 1.4 tc,\u00a0not baited, set up or called in<\/p>\n

But the adult was having none of it – this youngster is just too damned big for back-brooding. Here we see the foot of the adult (juveniles have darker feet) being used to…<\/p>\n

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\"westerm<\/p>\n

1\/2000, f\/6.3, ISO 400, Canon 7D,<\/em> Canon EF 500mm f\/4L IS II USM + 1.4 tc,\u00a0not baited, set up or called in<\/p>\n

make a quick turn to the adult’s right, which forced the juvenile off its back and dumped the young bird back into the water. At this point the youngster gave up and continued to swim away.<\/p>\n

I can only believe that this was an attempt by the juvenile to be back-brooded long after it was appropriate or even possible. I’ve spent hundreds of hours watching back-brooding grebes and there were several aspects of this behavior that were new to me.<\/p>\n