Last week’s Meadowlark Festival is a celebration of the natural world around us. It could not be better timed.
Most, if not all, of our migrant birds are back, antelope brush is in full bloom and while arrow-leaved balsamroot, our spectacular spring “sunflower” has gone to seed in the drier parts of the valley, some remain in flower and are joined by a changing pallet of colour as a procession of other wildflowers come into bloom.
The profusion of new plant growth coincides with the flight season of a rich assemblage of butterflies — probably the highest diversity in Canada. The next couple of weeks should bring the greatest abundance and variety of butterflies at low elevations in the valley — weather permitting.
Our earliest butterflies are those that have overwintered as hibernating adults. They have been on the wing on warm days since early March but, because of our remarkably cool April, are still around engaged in the business of producing the next generation.
The warm days of May have brought out a wave of true spring butterflies. These are species which have overwintered as pupae and first emerged as adults with the end of winter. The emergence of new species will continue over the coming weeks until early August, and some spring butterflies will have second or even third generations before winter sets in.
One of the fascinating spectacles among the butterflies emerging in spring and summer are “puddle parties”. These are often groups of related species — most notably swallowtails and blues — gathered at moist cutbanks, old firepits or drying puddles.
These aggregations are invariably all-male affairs and the attraction isn’t moisture per-se but salt which they extract from the damp soil. Prior to the industrial revolution, and the globalization of trade, salt (sodium chloride) was also a precious commodity for humans in many parts of the world
Sodium is too scarce in the vegetation that the caterpillar stage feeds on to meet the requirements of the eggs and embryos of the next generation. So while the female butterfly provides most of the protein and energy to the eggs developing in her body, the males donate sodium along with the sperm, in a gelatinous package called the spermatophore.
A “nuptial gift” as it were. Puddles are not the only sources of sodium — sweaty hikers are another convenient source, but it’s unusual to attract more than one butterfly at a time. Perhaps the most bizarre or disgusting source of sodium, and probably other nutrients, are carnivore feces.
Coyote dung seems to be especially favoured by anglewing butterflies. Seeing a group apparently feasting on such vile fare must be rather a shock to those used to thinking of butterflies as faerie-like creatures flitting amongst the flowers. But don’t pass judgment — remember they’re doing it for their “children”.
The next meeting of the South Okanagan Naturalists’ Club will be on Thursday. Lauren Meads, South Okanagan site co-ordinator for the Burrowing Owl Conservation Society of B.C., will present a program on the re-introduction of burrowing owls to the south Okanagan Valley, including how they are raised and the steps taken to release them safely in the wild.
The meeting starts at 7 p.m. in the basement hall of the Penticton United Church on Main Street. Everyone is welcome.
Dennis St. John is a member of the South Okanagan Naturalists’ Club, retired university professor and consultant wildlife biologist.