Banded Hairstreak (Satyrium calanus) (Hübner, 1809)

Diagnosis: This common hairstreak has a dark grey-brown underside with an irregular row of darker brown rectangular spots that form a band, edged with white on the outside. The blue spot on the hindwing underside does not have an orange cap. The upperside is uniformly dark blackish brown. Wingspan: 23 to 34 mm.

Subspecies: Subspecies falacer is found in Canada.

Range: The Banded Hairstreak is a widespread butterfly in most of the eastern U.S. In Canada, it hasbeen recorded several times in southern Nova Scotia and New Brunswick. In Quebec, it is found from north of Quebec City to west of Hull. It is a common butterfly in southern and eastern Ontario, north to Capreol, and is found from northwest Ontario, through southern Manitoba and into southeastern Saskatchewan.

Specimen collection data

Similar Species: See Edwards' Hairstreak (S. edwardsii) and Hickory Hairstreak (S. caryaevorum). [compare images]

Early Stages: The light green larvae, which turn brown just before pupating, have alternating light and dark oblique dashes on the sides. They feed on a variety of oaks, hickory, and walnuts, particularly Butternut (Juglans cinerea). Around Ottawa, RAL found that eggs are placed on Butternut so consistently at the base of buds on the previous year's growth that it is not difficult to find them, even during the winter. Egg hatching is synchronized precisely with the opening of the buds to ensure the newly hatched larvae only have to move a few millimetres to reach the new leaflets.

Description of this image follows.
Banded Hairstreak (Satyrium calanus falacer), larva. W. Lukey
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Banded Hairstreak (Satyrium calanus falacer), pupa. T. Arcand
Description of this image follows.
Banded Hairstreak
(Satyrium calanus falacer).
Ottawa, Ont. P.W. Hall

Abundance: The species tends to be the most common hairstreak in much of its eastern Canadian range, but is rarer in the west. Even where it is common, it can fluctuate dramatically in numbers from year to year.

Flight Season: The Banded Hairstreak flies from late June into late August in Canada. It is most numerous in July.

Habits: This hairstreak is associated with woodlands, where it can be abundant on milkweed and sweet clovers in some years. It is also common along roadsides and even in city streets where its foodplants grow.

Remarks: The subspecies falacerr was once considered a separate species.

© 2002. This material is reproduced with permission from The Butterflies of Canada by Ross A. Layberry, Peter W. Hall, and J. Donald Lafontaine. University of Toronto Press; 1998. Specimen photos courtesy of John T. Fowler.