here<\/a>)\u00a0was the color discrepancy I thought I saw between Sibley’s Western Kingbird illustrations and some I photographed about two weeks ago in northern Utah. Sibley’s illustrations show the colors of adult and juvenile to be “very similar” (almost identical to my eye) but the birds I photographed had significant, even major, color differences. In this image of those birds two juveniles on the right are begging for food from the adult on the left.<\/p>\nFriend\u00a0and regular contributor to Feathered Photography Dick Harlow brought my concern (and my blog post)\u00a0to the attention of David Sibley and yesterday Sibley responded with the following comment:<\/p>\n
<\/p>\n
“Thanks to Ron for posting some great photos and starting this discussion, and to Dick for alerting me to it. There is certainly a very clear difference between these two birds, and I did not do a very good job of capturing those differences in the guide. I wasn\u2019t trying to show the difference between a very worn adult and a fresh juvenile, but still, there are things that could be improved. <\/em><\/p>\nA lot of the difference in these two individuals in the photo is simply the age of the feathers, as others have already pointed out \u2013 brand new on the juvenile and almost a year old on the adult. In general among songbirds it is very easy to determine age this time of year, because the feather condition of adults and juveniles is so different. By November when the adult has molted to new feathers it will look a lot \u201ccleaner\u201d and more like the juvenile. It is also likely that juveniles are variable, with some very pale and others closer to adults.<\/em><\/p>\nDeciding what to show in the guide is always a balancing act. I usually opt for the \u201caverage\u201d rather than the extreme, and try to avoid showing rare variants or differences that are only visible some of the time (unless these involve real ID pitfalls, and in that case I illustrate the typical bird as well as the variant). Because the illustrations contain so much more information than could ever be in the text, it is unavoidable that readers will search the images for details, and even the slightest (sometimes unintentional) difference between illustrations might be picked out as a potential field mark. In the case of the Western Kingbird illustrations, I opted to make the adult and juvenile very similar, because they are really hard to tell apart except when you see a worn adult with a fledgling (as in Ron\u2019s photos), and I was also concerned about how they would compare with Cassin\u2019s Kingbird and other species.<\/em><\/p>\nNevertheless, I have some ideas now about how to represent these ages better in future revisions of the guide. It might involve adding a third perched illustration to show three ages: juvenile, fresh-plumaged adult, and worn adult. But that might require doing the same for all of the kingbirds\u2026<\/em><\/p>\nThanks, again, for bringing this up; learning is what this hobby is all about.”<\/em><\/p>\n <\/p>\n
I was fascinated to learn some of the things that go through David’s mind as he decides how to best\u00a0represent the physical attributes of a species in his illustrations. It must be a daunting task to attempt to illustrate the many plumage changes that occur in\u00a0a bird species\u00a0over time with just a few illustrations.<\/p>\n
I thought\u00a0his response was clear evidence that David Sibley is a class act.<\/p>\n
Ron<\/p>\n
<\/p>\n","protected":false},"excerpt":{"rendered":"
Last week I brought into question the accuracy of some of the illustrations in the Sibley Guide To Birds. David Sibley has responded.<\/p>\n
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![\"western](\"https:\/\/featheredphotography.com\/blog\/wp-content\/uploads\/2015\/08\/western-kingbird-0699-ron-dudley.jpg\")
1\/2000, f\/9, ISO 640, Canon 7D Mark II, Canon EF500mm f\/4L IS II USM +1.4 tc, not baited, set up or called in<\/strong><\/em><\/p>\n