Soon afterwards he returned to Kőszeg and devoted himself to ornithology. In 1890 he was a nationally acknowledged researcher, who had already been to almost every part of the country watching birds and taking notes. In 1891 he travelled to Norway with his wife to the island Tromsö. He published a book about this trip titled Travel to the Faraway Norway in which he wrote about his geological, geographical observations as well. A separate chapter of the book is devoted to the Lapps introducing their culture, ancestral traditions and language.
Returning home he popularized skiing as a sport and wrote a book about it as well. His work was a great step in introducing skiing in Hungary.
His main work Birds of Hungary with Special Respect to their Economic Significance was published in 1899. This was the first ornithological work of Hungarian authors. The aim of his thick, two-volume work was giving advice to experts of the economy. The first volume is about the role of birds, their place in nature and their anatomy. The second volume expounds the taxonomy of birds and after deals with all the bird species of the country. Beside their Hungarian and Latin names the author gives their popular names and describes their behaviour vividly. This work is the result of 22 years of collecting data during which he explored the country and got to know the different peoples living here. The book made its author well-known in foreign circles of experts, too.
He contributed to preparing the new, jubilee publication of Naumann’s seventeen-volume Naturgeschichte der Vögel Mitteleuropas. He translated the volumes on birds in Brehm’s Tierleben (The World of Animals) into Hungarian and supplemented them with Hungarian data.
In 1902 he established the Kőszeg group of the National Animal Conservation Association. In the same year he organized the first „Day of Birds and Trees” in Kőszeg. He founded the natural history department of the Vas County Museum and prepared the collection of the birds of Vas country.
In 1916 he was trusted with the leadership of the Royal Ornithological Centre of Hungary. In 1918 he assembled the list of the Hungarian birds (Nomenclator Avium Regni Hungariae).
During the long years of collecting work the illnesses
he had caught in the swamps and moors had weakened his health. In
an unheated railway compartment he caught a cold and he died of pneumonia
at the age of 57 on 21st February 1922 in Kőszeg.