In the far off distance, a hushed whistling sound can be heard. No, it’s not a gaucho passing the time, but the unsuspecting call of the oft-silent black-necked swan calling to its mate. Unlike the abrasive squawks and honks of other swans, the black-necked’s communication skills seem lacking at best. Spend a little time observing this bird, however, and you’ll quickly note its subtler mode of interaction that’s predominantly visual.
A dip of the head, a flap of the wing, the black-necked swan – or Cygnus melancoryphus – begins its ceremonial mating dance. Given that they mate for life, the male swan understands the importance of his next moves. Typically quiet and docile, he becomes aggressive and territorial during this ritual. Once he’s landed his mate, however, he returns to his good-natured self to participate in the customary, post-copulation bath that cements the new pair’s bond. Black-necked swans utilize tactile stimulation throughout the lifespan: for instance, females groom young cygnets to teach them to clean themselves, and both parents carry their babies for the first three weeks of life.
Speeding gracefully through the air – up to 50mph! – black-necked swans swarm the Patagonia region come July just in time for breading season. Designed to fly at such speeds, these swans are almost incapable of walking on land. With stumpy little legs positioned far back on their bodies, black-necked swans struggle to take flight. Once airborne, they compensate for their awkward gait on land with strong flying skills that allow them to migrate northwards to Paraguay and southern Brazil during the austral winter.
Though black-necked populations are stable at present, thousands of these swans in the Carlos Anwandter Nature Sanctuary in Chile died or migrated away following major contamination from the Valdivia Pulp Mill in 2004 and 2005. Owned by a Chilean wood pulp and forestry company, CELCO, the mill is located on the Cruces River that feeds the surrounding wetlands. High levels of iron and other metals polluted the water, decimating the black-necked swan population from 5,000 strong to just 4 birds. The plant was closed in 2005 after CELCO’s lawyers produced a false environmental study reporting on pollution in the Cruces River; this scandal prompted CELCO’s chief executive to resign and forced the company to pledge $614 million Chilean pesos to Valdivian tourism.
Black-necked swans play the critical role of “manager” of the aquatic plant population within their habitat, as they prefer to maintain a mostly-vegan diet. Given that water conditions are improved through the regulation of aquatic vegetation, we’re pleased to report that the black-necked swan is thriving in the future Patagonia National Park. Flocks can be found in the many lagoons bordering the road that runs through the park, giving visitors the opportunity to see and appreciate this particularly beautiful bird.