In Stephen Sondheim's "A Little Night Music," a group of characters gathers for "A Weekend in the Country" during the endless days of a Swedish midsummer.
After a winter of both literal and emotional darkness, they lose their inhibitions. Romance, intrigue, jealousy and infidelity fill the magical Scandinavian summer.
Oddly enough, much the same thing happens among the breeding birds of North America.
Both year-round residents and migratory songbirds pair up and raise their young during the long days of late spring and early summer. Food is plentiful, and the extended daylight gives parents more time to forage and feed hungry nestlings.
Ornithologists doubt that birds experience human emotions such as romantic love or jealousy. Yet, midsummer is a time of surging hormones and intense competition.
In many species, males devote enormous energy to defending territories, singing to attract mates, and keeping close watch on their partners.
And despite appearances, not every avian relationship is entirely faithful. Scientists use the polite term "extra-pair mating" for encounters outside the breeding pair. Modern DNA studies have revealed that a surprising number of nestlings are not fathered by the male tending the nest. In some species, a single brood may contain both full siblings and half-siblings.
The tangled relationships in "A Little Night Music" are driven by ego, desire and romance. In the avian world, midsummer mischief serves a different purpose. It is simply one more way of passing genes to the next generation before the long nights return.
For birds and humans alike, the shortest nights of the year can lead to surprisingly complicated relationships.
