Cozy 1BR, Forest Vu

Natural History, May, 2004 by Stephan Reebs

Come springtime, birds everywhere are busy nesting and reproducing. But not every bird gets to breed--before you can raise a family you usually need a place to call home, and young adults are often edged out of the housing market. Those birds become floaters, sitting out the breeding season and presumably moping. A recent study, however, suggests nonbreeders make the best of a bad situation.

Michael Tobler and Henrik G. Smith, both animal ecologists at Lund University in Sweden, watched common starlings and their attendant floaters throughout the starlings' breeding season, in May. The two investigators found that male floaters stay within specific areas, covering about one aquare mile, and often visit the nesting cavities (tree holes) used by the breeders, particularly when the young are still inside. Apparently the floaters are checking out real estate that may become available the following year.

Tobler and Smith also set up empty, nestworthy boxes in the fall, before the starlings migrated, so that the birds could visit them; the following spring those boxes were occupied. Other, equivalent boxes were installed in winter, when the starlings were gone. Yet despite the housing shortage, most of the unexplored boxes remained empty the following spring. Evidently the birds prefer advance planning. ("Specific floater home ranges and prospective behaviour in the European starling, Stumus vulgaris," Naturwissenschaften 91:85-89, February 2004)