2017 May 21

 

   Ken Vaughan photographed a Swift Forktail at Beaver Lake Pond yesterday.

 

Swift Forktail Ischnura erratica (Odo.:  Coenagrionidae)  Ken Vaughan

 

  Jeremy Tatum writes:  Today Bill Savale and I walked along the railway line north of Cowichan Station.  There were a few Margined Whites Pieris marginalis  there, nectaring, as they often do, on Herb Robert.  There was a lot of Nasturtium in the adjacent ditch, and also a lot of Hesperis at the side of the ditch.  I think Nasturtium is probably the favoured larval foodplant, though in the past I have found and successfully reared them on Hesperis.  The butterflies we looked at were completely immaculate white above.  They are often completely white underneath, too, but, in the one we had a good look at, the veins on the underside were boldly marked in grey, looking very like the European Green-veined White Pieris napi.   The immature stages of the two seem to be indistinguishable, and a case could be made for lumping them both under the name Pieris napi.

 

  The flight of the Margined White is lighter and more floatier than that of the Cabbage White.  Not so light as that of the Pine White, but something in between.

 

    There were also a few Western Spring Azures there, and I saw my first Satyr Comma of the year.