An affinity for open, shrubby wood-lands, mimicked so well by small town and suburban backyards and city parks, a preference for human-made “bird houses,” and a very loquacious nature all combine to make the House Wren one of the best-known songbirds in North America.
The first edition of this summary of House Wren biology, prepared in the mid 1990s, said that “House Wrens are arguably the most thoroughly studied passerine in North America, in part because they so readily use human-made nest sites, and because they are ubiquitous, relatively abundant across most of their range, and tolerant of human activity.” Now, two decades later, one can readily argue that we know more about the biology of the House Wren than any other wild species of bird in the world. New studies have focused on genetics, immunology, energetics and physiology, ecology, demography, reproductive and other behavior, sex allocation, communication, systematics, and more. As of the mid-2010s, more than 700 research papers, government reports, theses and dissertations had been published that touched on one or more aspects of House Wren biology.
House Wrens occupy the broadest latitudinal range of any native passerine in the New World, breeding from across most of Canada down to the southernmost part of South America, and into the West Indies. The number of studies done on southern forms of house wrens have increased recently, especially in Argentina and Chile. Coverage of research done on southern forms has been greatly expanded in the current review of House Wren biology, with an emphasis is placed on studies that would be of most utility to researchers studying the northern forms. However, the existence of other studies on southern forms is noted and all known studies of the species appear in the comprehensive bibliography found at the end of this review.
Despite the considerable amount of research done on this species to date, there remain many gaps in our knowledge of this species' biology. In addition, because House Wrens exist in such a variety of locations and under such a diverse array of abiotic and biotic conditions, they present an almost unparalleled opportunity to study how environmental conditions shape the morphology, physiology and, especially, the behavior of birds. That the House Wrens is also abundant across the range of the species, easily attracted to nest boxes, and remarkably tolerant of human activity makes this species something of a gift to ornithologists, one that they will surely continue to unwrap in the decades to come.