Colombian artist Fernando Botero had his ranch outside Bogota burglarized Thursday while he was in New York. The painter and sculptor, famous for his rotund figures, said that 15 armed men tied up the caretaker and his family early in the morning, killed two dogs, then cut through the metal door of a vault and took 17 paintings and three sculptures "of great sentimental value." Neighbors found the family unharmed that evening, and the Colombian Federal Police are investigating the incident. Botero, still in New York, believes that the robbers "went into my ranch to kidnap me." He added that he will not return to his home "as long as the situation of danger in my country persists." Symphonic Datebook

When Leonard Bernstein announced his retirement from conducting Tuesday, it left some holes in the schedule of the New York Philharmonic. Kurt Masur, who was already slated to take over from Zubin Mehta as music director of the Philharmonic next fall, will raise his baton in place of Bernstein for the orchestra's December performances of Mendelssohn's "Elijah." To make the dates, Masur had to postpone a recording session with his current orchestra, the Gewandhaus of Leipzig, Germany. The Invisible Princess

Poor Princess Anne. She dropped into New York City on Thursday for a two-day visit, only to have one resident say, "If I saw her on the subway, I probably wouldn't even know who she was." She was in the city's Seaport district to dedicate a building for the British Seamen's Church Institute, of which she is president. The daughter of Britain's Queen Elizabeth II was wearing a bright yellow suit with blue gloves, but just couldn't generate the excitement that her sister-in-law Princess Diana does on her public visits. Israel Chernow, a resident near the dedication site, said of the princess, "I was quite impressed, but I really came to see the building." All this despite what a close friend of Princess Anne's says in the recent special edition of People magazine on the royal family: "{Anne} can be terribly sexy, really turn it on," even though she inherited that "endearing royal overbite and disappearing chin." Gourmet a la Greyhound

John Munro, a vice president of the Greyhound bus company, has a plan to get his terminals' bathrooms clean. He's been dropping into stations around North America and sitting down to a gourmet meal with the terminal managers in their restrooms. A bit dramatic, but it apparently gives managers who haven't yet been visited a little incentive to clean up their act. Munro thinks it makes the point quite well. "If I can't offer you a clean environment, I shouldn't be in business." A Vancouver, B.C., dinner of duck and champagne has had the nicest ambiance so far, according to Munro. Marriages Made in Heaven

Sen. John Glenn was among those surprised to read here yesterday that his longtime friends, composer Henry Mancini and his wife of 43 years, Ginny, had parted ways. After a quick call to the Mancini home in California, the Ohio Democrat learned the truth: The Mancinis are still happily hitched. Glenn, married to his wife, Annie, for 47 years, said after talking to Mancini, "Hank and I have always thought we married above ourselves, and we have no plans to change that."