{"id":41435,"date":"2016-08-13T06:24:24","date_gmt":"2016-08-13T12:24:24","guid":{"rendered":"http:\/\/www.featheredphotography.com\/blog\/?p=41435"},"modified":"2016-08-13T06:58:58","modified_gmt":"2016-08-13T12:58:58","slug":"western-grebes-an-optical-illusion-and-a-behavior-new-to-me","status":"publish","type":"post","link":"https:\/\/featheredphotography.com\/blog\/2016\/08\/13\/western-grebes-an-optical-illusion-and-a-behavior-new-to-me\/","title":{"rendered":"Western Grebes – An Optical Illusion And A Behavior New To Me"},"content":{"rendered":"

Apologies for posting the same species two days in a row but yesterday I got a grebe\u00a0twofer – an optical illusion and a behavior\u00a0I’d never seen before.<\/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<\/strong><\/p>\n

Ok, first the optical illusion. These are both Western Grebes. The bird with the bright red eye is the parent of the juvenile with the grayish head. The juvenile is almost full-grown and just about the same size as its parent. Please study the image for a few moments and decide what you’re seeing.<\/p>\n

It appears (to me at least)\u00a0that the adult has its back\u00a0to\u00a0the viewer\u00a0and\u00a0is swimming away from us and directly into the outstretched neck of the juvenile whose body we see lengthwise in the water. But that’s far from the case and I’ll\u00a0demonstrate that fact by showing you photos of what happened before and after this image was taken.<\/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<\/strong><\/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<\/strong><\/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<\/strong><\/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<\/strong><\/p>\n

and bend its long neck to the right as its body began to slip over the top of the front of the body of the adult.<\/p>\n

This is the image I presented first. Now it should be clear that what we thought we saw in the first image was really an illusion. The body to the left\u00a0actually belongs to the red-eyed 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<\/strong><\/p>\n

As the juvenile continued to push forward its body began to go over the top 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<\/strong><\/p>\n

And then 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<\/strong><\/p>\n

The weight of the very large\u00a0young 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<\/strong><\/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<\/strong><\/p>\n

make a quick turn to its right which forced the juvenile off its back and dumped it back into the water. At this point the young bird 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. There were several aspects of this behavior that were new to me and I’ve spent hundreds of hours watching back-brooding grebes.<\/p>\n