Prothonotary Warbler

Prothonotary Warbler

Wednesday, 25 May 2016

A picture doesn't always tell it all

My previous post highlighted some of the wood warblers I have seen at Rondeau this spring. Typically only one image per species was used. And that created a problem....hence this post.

I included this image of a Northern Waterthrush.
And that elicited a comment by a well-known Ontario birder that it should be re-labelled as a Louisiana Waterthrush.

I can't say that I blame Brandon for this comment. He is a highly respected and knowledgeable birder, and has served admirably on the Ontario Bird Records Committee (OBRC) for several years. From the angle showing this bird, the image does have some characteristics of Louisiana: the broad light coloured supercilium and the appearance of fewer, more spaced out darker streaks on the flank. However, and this is the reason for the title of this post, this single picture doesn't tell it all.

This next one is of the same bird taken three minutes earlier.
In this one, the yellow wash over the entire lighter part of the feathers is obvious, but what is more telling is the heavily streaked marks on the breast feathers. Even more conclusive is the numerous finer streaks in the throat region. All of these clearly identify this as a Northern Waterthrush.

Had the bird been singing, it would have helped, but this one was quiet.

Almost exactly a year later, I photographed this waterthrush within a short distance of the Northern Waterthrush. It wasn't singing either.
 In this side view, the overall light colour of the bird is decidedly white. The streaks on the flank appear to be few and widely spaced.
This bird hopped up on the railing along the trail, and here one could see the streaks on the breast, but they aren't as densely spaced as the Northern Waterthrush above. And again, quite conclusively, is the white unspotted throat. This bird is the much rarer Louisiana Waterthrush.

I realized after posting the previous 'Warbler Parade' blog and reading Brandon's comment that for a more challenging species it would have been helpful to include additional supporting photos to substantiate the identification. I expect that is why bird field guides are more useful when they show illustrations rather than photos. A good illustrator can often show all the important characteristics in one or two illustrations, whereas it might take half a dozen good photos to do the same.

Over the years, I have had single images of birds sent to me for identification. I'm sure many reading this post have received some also. While some images are relatively easy to figure out, when a single photo is received that does not show the critical characteristics, one is left with making an educated guess.

I am sure this is a dilemma for members of the OBRC. Sometimes a single photo is all that is received, and without the critical characteristics being shown, it can be difficult to accept or reject a rare record. I admire the willingness of the OBRC members to sift through the various types of reports from year to year, to decide what records are acceptable and what records are not!

So thanks, Brandon, for the comment on my previous post, and for indirectly pointing out the need for me to be more thoughtful in labelling certain types of images!





4 comments:

  1. What a great example and some useful field id tips for the two Waterthrushes!

    I take photos of every glimpse of a bird that I can. It's often something like the undertail coverts or what not that can help make the call if the bird is in dense cover. Of course anyone who knows me knows that I am NOT an expert birder so I need all the help I can get!

    Another thing that works for me is flipping the camera onto video and capturing the song. It doesn't matter if I get video of the bird while it's singing, the microphone will pick up fairly well even when not aimed anywhere specific. I think some people forget this possible way to audio record easily.

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    1. Thanks, Bet. Numerous photos of some birds definitely can make a difference when you have the time to view them on a computer screen at a later time, rather than relying on a few seconds of viewing them live. Good hint about the video feature to capture the audio.

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  2. Well I guess per my earlier comment - I'd be wrong if I switched it (!) - sure looks like a LOWA in that image.. Thanks for a great post.

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    1. Thanks, Brandon for making me realize that my first post was incomplete in the sense that the photo I used did not permit the true ID.

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