Conrad Gesner fully shared Belon's love of wild birds. He was a student of the anatomy of birds—as much so as Belon, and more perhaps than Aldrovandi, because Aldrovandi generally persuaded a professional anatomist to act as his prosector. But Conrad was also a good field-observer, with eyes and ears trained to detect the passage of migrating flocks. He took a great interest in the rarer birds of the Swiss cantons. He was cognizant of two or three breeding stations of the Black Stork, one of which was in the neighbourhood of Lucerne.
Gesner was well informed regarding the habits of the Black Stork, which he describes as nesting in trees, usually pine-trees. He dissected one of these birds which had been procured near Zurich. It had been feeding upon beetles and other insects. He remarks that this Stork had a fishy smell; such a bird should first be boiled, and then stuffed with herbs. The flesh was good and sweet, but the skin proved tough. Very pleasant reading is afforded by Gesner's account of the Bustard. The Great Bustard was not a common bird in Switzerland in the sixteenth century. Nevertheless, several of the birds which Gesner examined had been killed near Zurich, or near Coire, in the Tyrol. Conrad had the curiosity to weigh a couple of Bustards. One of these birds scaled nine pounds twelve ounces; the other turned the scales at thirteen pounds and a half. The stomachs of these birds were filled with vetches, but Bustards which had been killed in heavy snow contained pebbles and the bark of trees. Conrad Gesner was told that Bustards were "permultos in Anglia," but whether he owed this piece of information to John Falconer, Thomas Gybson, John Estwyck, to Turner, or Dr. Caius, has not apparently been solved. Gesner corresponded with all five of these British naturalists.
Gesner examined many other birds of local interest—such, for example, as a Spoonbill killed near Zurich in the month of September. The early nesting proclivities of the Crossbill were as well known to this great Swiss as its variations of plumage. He studied the seasonal changes of the Ptarmigan. Friends at a distance often sent birds to be described by Gesner—e.g. the Stilt, the Purple Waterhen, the Pin-tailed Sand-Grouse. The most remarkable perhaps of all his discoveries was that the rare Bald-headed Ibis, now lost to Europe, nested on the lofty walls
