Charles Darwin believed that the brilliant colours of such birds as peacocks and cardinals evolved largely as a means to win female affection. Since then, many scientists have assumed that the gaudiness of male birds in some species suggests greater competition for mates and that males in dull-coloured species are freer from the pressures of sexual selection.

Not necessarily, say biologists at Queen’s University in Kingston. Using a penlike sensing device called a spectrometer, the researchers have revealed the unseen truth about the drab feathers of black-capped chickadees.

To most of us, these small, black=and=white=and=tan birds are indistinguishable from one another.\, males and females alike. With the spectrometer’s help, however, the biologists found male chickadees are visually dazzling compared to females, with brighter whites and greater contrast. The caps and bibs of the most sexually successful males reflect more ultraviolet – a colour invisible to humans.

“We don’t know that females use this information when they choose males,” says Stephanie Doucet, a post-graduate researcher who helped lead the study, “but it’s available, and it’s indicative of reproductive success.”

The findings dovetail with research showing that birds’ eyes see more colour and with greater acuity than humans can. It also suggests that the evolution of plain-looking animals may be affected by sexual selection in ways to which we are simply blind.

Just what exactly is a switchback?

A switchback is a trail up a steep hill or mountain that is like a zig-zag pattern instead of a straight trail. The zig-zag pattern protects the hill and the trail from excessive erosion. Trails that go straight up and down steep hills don’t stay nice trails for long. Erosion turns them into gullies because water moves faster down steep straight-aways and it hollows out the trail and washes all the soil and vegetation downhill.

Switchbacks help prevent erosion because they help keep the trail at a consistent gradient. Trail planners build other erosion control devices like rolling grade dips into switchbacks also. Switchbacks are also good because they make it easier to climb steep hills.

“Short-cutting” a switchback is bad trail etiquette because it kills vegetation and loosens soil, creating a new trail straight up and down the hill which will, in time, get large and hollowed out from erosion. Do your part to keep our trails beautiful and control erosion. Walk softly, Leave No Trace, and stay on the designated trail.