Thursday, 2 September 2010

Darters - Common or Ruddy?

There are two species of Darters that at first glance may look very similar and can be easily confused for one another so I thought I would share some very recent images.
The Common Darter (Sympetrum striolatum) is the larger of the two with an abdomen length of 25-30mm. Both species will perch with the wings held forwards.
Immatures and female Common darters have a yellowish to light brown abdomen. Mature females take on a much darker hue. On both males and females the divisions between the abdominal segments are much more prominent than on the Ruddy.
Both the male and female Common have two distinct yellow patches on the side of the thorax and this is a clear feature to assist immediate identification. Both the males and females have a similar tiny basal yellow spot on the wings (similar to the Ruddy).
The abdomen of the mature Common males is orange-red and therefore much lighter than the blood-red colouration on the Ruddy. Often very difficult to see are the yellow stripes on the legs.  
When viewing side on you should note that there is no black line extending down the length of the abdomen.
The Ruddy Darter (Sympetrum sanguineum) is smaller than the Common (abdomen length: 20-26mm) and the mature male has a distinctly waisted blood-red abdomen and much darker sides to its thorax (see below) and the black line over the fronds extends fully down the sides. The legs are totally black whereas the legs on the Common are striped with yellow but extreemly difficult to pick out with your eyes. It also has a similar tiny yellow spot at the base of the wing.
So next time you are out and about keep a watchful eye open for these two species which often share similar habitats. They will be around for a while yet (even into late October) and hopefully you will now know which is which.    FAB.

19 comments:

  1. My favorite is the ruddy. Love the red. Hope all is well with you and yours. Carol

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  2. Beautifully explained Frank with wonderful photos too. I'm not aware of having seen Ruddy Darter, so I'll definitely be on the look out now for the tell tale signs. Hope all is well with you!

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  3. GREAT NOW I CAN PUT A NAME TO ANOTHER ONE OF OUR SPIECIES'

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  4. Great post Frank. They can be tricky to tell apart; especially if you only get a fleeting glimpse.

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  5. Thanks Frank, I will not forget them.

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  6. That's great thanks for posting that article, Ive struggled in the past to tell the difference so I found your post really helpful. Linda

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  7. THanks for the info and the photos. I have been looking for them while I am out birding.

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  8. Great set Frank and the ID was very informative thanks.

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  9. ou photos and descriptions were helpful, Frank. My problem is usually getting these frisky fellows to stay put long enough to have their photo taken. We don't get too many in our yard, but I have seen a few more in recent weeks in the wildflower garden areas.

    Hope your family is holding up and you too.

    And, I can understand about not having time to read and reply to all the blogs we tend to follow - same problem here. So much interesting sruff and so little time to do it all.

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  10. Exquisite photos! I don't really know one from the other, but loved your explanations.

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  11. Hi Frank ....Someday I hope to be able to get photos like your....but I guess I could just keep looking at yours ; }
    Love those guys.. love the colors ..big buggy eyes...I don't believe I will ever remember which is which...informative post and great photos!!
    This is Labor Day weekend holiday here and we also have the potential of some damage from hurricane Earl!!
    Hope I don't lose my internet : {
    Hope everything is ok with you and your family !!

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  12. Excellent photos! Thanks for all the great information.

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  13. Wow they sure do look so much alike. I just posted one that I am not certain of, due to it looking like two that I have looked up and just not certain which it is~

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  14. Hi Carol. I'd find it hard to choose as they are both facinating to watch. No change on the PJB front...we are still watching and waiting.

    Hi Jenny. We hopefully you will now find one with ease.

    Hi Tony. Glad to be of some help.

    Hi Keith. Cheers my friend. Far too many fleeting glimpses of some species!

    Hi Bob. Good for you.

    Hi Linda. Comparing the images after the event if you are unsure is always a help.

    Hi Eileen. Hope you catch up with them soon.

    Hi Monty. Cheers.

    Hi Beatrice. As always patience is the key as they have eyes that see every little movement. Good time of year for the late flyers. We are doing our best to stay level headed at the moment.

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  15. Hi Mona. Thanks and hopefully you'll know one when and if you see it.

    Hi Grammie. I'll keep posting a few as long as you keep looking!
    Hope you stay safe from the full force of nature.
    We are all still waiting and watching PJB..no change at the moment..could be a long wait.

    Hi dAwN. Very nice to hear from you.

    Hi Mary. Yes, sometime difficult to seperate. I have little knowledge of all your US species but hopefully one og your readers will come to the rescue.

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  16. What a great post Frank!! The pictures are stunning too. Sometimes it is very difficult to tell the differences and to make it more confusing, the males and females are sometimes completely different colours. :)

    I am off to see some orchids this morning and hope I can get nice pics of them to post.

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  17. Hi Joan. Cheers. Sometimes far too confusing for my liking!
    Look forward to loking at the Orchids.

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  18. Hi Frank...I had to laugh at your last reply...'sometimes far too confusing for my liking!'...referring to Dragon I.D.

    NOW...You know how I love the dragons, but I have to agree with you on this one! Wonderful captures, Frank! Great I.D. info as well.

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  19. Hi Kim. Well at least I don't have the variety like you to contend with ... would be fun though! Coming from the 'dragonlady' I appreciate the compliment. FAB.

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