The sightings and occasional thoughts of an English birder in Oslo
Monday, 22 October 2018
Late Common Darters in Maridalen
I have
posted a few pictures of dragonflies this summer and my interest in them is
growing although my identification abilities even with good photos is still
poor. I find separating Common Darter (sympetrum striolatum) and Vagrant Darter
(sympetrum vulgatum) especially difficult and often have to send my pictures to
Finn Mosti for help.
On
Thursday I was surprised to find a number of darters in Maridalen with both egg
laying and mating observed. The birds were clearly weak with it being so late
in the season and allowed close approach. One female also seemed to find egg
laying too much and her mate just dropped her in the water but I guess her job
was done and she could bow out knowing she had fulfilled her destiny.
It was
interesting watching them egg laying with the male holding the female by the
head and also mating where they are attached in two places with the male
holding the females head and them then attached by their sexual organs. In the
video you can see the males body pumping as he presumably transfers his sperm
to the female.
I had
concluded that they were Vagrant Darters based on the shape of the sexual
organs but the expert opinion is that they are Common Darters (although the egg laying ones cannot be safely identified from these pictures)
Common Darters/sympetrum striolatum/senhøstlibelle
an unpaired male
another male
presumably also Common Darters
the female after being abondoned by the male once the job was down
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