The phenology records at Mohonk House are, in many ways, a model for such observations. They were compiled, in large measure, by Mr. Huth and the naturalist he succeeded, Daniel Smiley Jr. Mr. Smiley, who died in 1989, was a beloved descendant of the two Quaker brothers who founded Mohonk House in 1869. He dedicated much of his life to keeping lists of everything he saw and heard on the mountain, collecting whatever was of interest to him and labeling it carefully for future use.

Mr. Smiley kept his phenology records as meticulously as he “did the weather” for more than 50 years, for which he earned the National Weather Service’s highest award, named for Thomas Jefferson.

Image Paul C. Huth collecting data at Mohonk House. Credit... Chris Ramirez for The New York Times

He walked the extensive grounds of the resort making notes about every bird call he heard, every animal he saw, every budding flower and flowering tree. Back in his office, he transcribed those notes onto 3-by-5 cards (many early ones were written on the reverse side of the hotel’s old menu cards). Over time, he amassed more than 14,500 cards with notations like this one, from March 28, 1929, filed under “partridge”: “Near Duck Hawk ledge on Sky Top saw one ‘treading’ another, with great commotion down in a brush pile in a crevice, while a third looked on. Too dark for a picture.”

In 1978, the Smiley family carved out 6,500 of its acres around the hotel to form the Mohonk Preserve, the largest nonprofit nature preserve in New York State. In 1980, the preserve created a research center that was named for Mr. Smiley after he died in 1989. Mr. Smiley was an old-school amateur naturalist, but his observations have proved to be solid scientific evidence. For instance, when the hotel’s chlorination system started acting up in 1931, he began taking water temperature and acidity readings. He was surprised to find that the water was unusually acidic, a pH of around 4.5, but he did not know why and just filed away his notes. Jump ahead 40 years to the early 1970s, when acid rain became a concern. Mr. Smiley dug up his old notes and sent them to the Environmental Defense Fund, which used the data as a baseline for extended studies of acid rain.

Similarly, in the 1950s Mr. Smiley found on his walks that the use of DDT to control gypsy moths was killing all kinds of insects, and that the peregrine falcon had nearly disappeared from the Shawangunks. He ordered all spraying stopped on Mohonk land. Of course, DDT spraying was later banned.

Last year, Benjamin I. Cook, a climate modeler and post-doctoral fellow at the NASA Goddard Institute for Space Studies, and his father, Edward R. Cook, a tree-ring specialist at the Lamont-Doherty Earth Observatory who met Mr. Smiley in 1971 when he was a military policeman at West Point, published a study in The International Journal of Climatology. They analyzed Mohonk House data to determine how some overwintering birds, insects, animals and 19 species of plants had changed their habits in accord with changes in temperature.