Dr. Niko Tinbergen was well known as a naturalist and a student of animal behaviour in England, on the Continent and in the United States. Ever since he was a young student in Holland he had been curious about nature, and in this book he sets out some of the facts that 25 years of curiosity gave him.

As a biologist, anything living was his province—the bee-killing wasps and the digger wasps of the Dutch sand dunes; the Snow Bruntings and Phalaropes of Greenland; Hobbies and other hawks; moths and butterflies in various parts of England and Holland; Black-headed Gulls of the Ravenglass nature reserve, Cumberland, the Kittiwakes and Eider Ducks of the Farne Islands off the coast of Northumberland.

Readers cannot fail to be struck—and possibly sometimes amused—by the patience and ingenuity shown in the field studies undertaken by Dr. Tinbergen and his fellow naturalists—and which are now passed on for the benefit and interest of his readers. The studies were always undertaken seriously, but this did not prevent Dr. Tinbergen from writing about them in the liveliest way; he realised that quite often he and his friends must have seemed to onlookers to be very curious naturalists indeed.