Newswise — In an unusual research collaboration, a University of Massachusetts Amherst geoscientist, Douglas Hardy, and his son Spencer, 14, recently reported what is believed to be the first well documented evidence of a bird other than a penguin nesting directly on ice, in the Andes Mountains.
The elder Hardy, a glacier specialist with the university's Climate Systems Research Center, found evidence over the past four seasons of studying climate on the Quelccaya Ice Cap high above Cuzco that a bird species was nesting on the glacier. Spencer, an accomplished amateur student of birds and their nesting habits, was in sixth grade at the time he identified White-winged Diuca Finches from photographs and began helping to interpret evidence that they were responsible for the nests. He is now a freshman at Hanover High School, New Hampshire, near the family's home in Norwich, Vt. The jointly authored father-son paper appears in the September issue of the "Wilson Journal of Ornithology" .
Douglas Hardy says, "I never would have tackled this without his interest. But it's been stimulating and enjoyable working on this puzzle with Spencer." The researcher attributes their discovery to his son's scientific curiosity. "I'm really delighted that Spencer followed his passion and his desire for knowledge about this, which motivated me as well. I was lucky enough to be on the glacier in Peru doing the fieldwork, but he was a full partner in putting the paper together."
For his part, Spencer says, "The breeding habits of birds around here [at home in the Connecticut River valley] are pretty well established, so it's cool being able to report on such a different nesting strategy. Not only that, but we've documented nesting in a really extreme environment, at what must be very close to the climatological and physiological limits where birds can live and breed."
The UMass Amherst climate scientist says he had been visiting the ice cap at nearly 19,000 feet for several years during the southern winter months of June to August to study the retreat rate of its ice margin, estimated to be about 1 meter per year in this area. In 2005, he told his son, the budding ornithologist, about finding several places where grassy nest material was frozen into the ice above, with upset nests on the gravel below, apparently having fallen from the glacier.
Although Hardy's collaborators had seen old nesting material around the ice margin on past expeditions, they had not investigated further. The elder Hardy had never seen anything like this on glaciers anywhere in the world, and the younger had never read of such a nesting habit. Intrigued, they wondered whether the evidence showed that the sparrow-sized birds were incubating eggs directly on the ice " behavior previously attributed in the literature only to penguins.
Beginning in 2005 and for the next four seasons, the elder Hardy made time during his research trips to search sections of Quelccaya's ice face. Once focused, he found 14 nests in 2006 and 16 in 2007 that seemed clearly to have fallen off the ice edge as it melted; no evidence was found for off-glacier nests. However, identifying which species built and used these nests remained a big challenge. One of the Hardys' approaches was to consult a feather expert at the Smithsonian Institution.
Finally, on his most recent trip in June 2008, after their paper was written, Douglas Hardy found intact Diuca Finch nests on the ice that had not yet fallen, and one contained abandoned eggs.
Like penguins, these small birds endure brutal nesting conditions for weeks on end " low oxygen, bitter cold, heavy snow and high winds. Few people have visited this ice cap during the breeding season, believed to be in April and May, and birds on nests have not been observed, the father and son report. In fact, "little information exists on nesting habits of this species from anywhere in the Andes," except that they do not retreat to lower elevations even in winter, and immature birds have been seen in June.
White-winged Diuca Finch nests are "bulky structures" that start from a platform of grasses and twigs and gradually taper up to form a woven cup about 2.5 inches in diameter, so the eggs rest about 10 inches off the ice. The cup contains finer grasses and feathers of other birds found in the area, but no alpaca or vicuna fleece, the researchers report. The whole nest often weighs just under half a pound, Hardy and Hardy note.
The geoscientist says that while it's not known what effect the apparently increasing rate of ice edge retreat will have on the hardy little glacier-nesting birds, there are already indications that changes in glacial streams and melt water paths are affecting wetlands where the finches " and other birds " get their grasses and other nesting material. As Hardy continues his climate research on Peru's Quelccaya Ice Cap, he will be documenting changes in Andean climate which are likely to affect not only birds and animals living high in the mountains, but also downstream human communities where people rely heavily upon the glacier as a water resource.