Sedge Wren
Cistothorus platensis

Migratory Status: Short-distance migrant

PIF Population Estimate: 6 500 000

Percent of western hemisphere population breeding in boreal forest: <25%

PIF Maximum Detection Distance (m) : 125

Canadian BBS Population trend: 1.7 n.s. (-0.3 to 3.7)

Life History

Sedge Wrens have several disjunct populations across the Americas. The North America population occurs in the eastern United States, south of the Great Lakes and throughout the northern Mississippi valley. In Canada, the population spans southern Ontario and Quebec and the southern halves of Manitoba and Saskatchewan, except for the southwest corner of Saskatchewan. The song of the Sedge Wren is a “dry staccato chattering”, beginning with 3 or 4 introductory notes, followed by variety of trills. Only the male sings, both during the day and night.

Sedge Wrens are one of the smallest wrens in North America. Adults are similar in appearance. Generally sandy-buff to cinnamon in colour, Sedge Wrens have a boldly streaked crown, back and tail with a lighter, unmarked throat and belly. The closely related Marsh Wren is distinguished by its different song, slightly larger size, longer bill, darker cinnamon colour and is less streaked. As their names imply, Sedge Wrens are typically found in damp grassy meadows or sedgelands, while Marsh Wrens prefer wetter cattail marshes.

Unusual among terrestrial birds, Sedge Wrens are nomadic breeders. Pairs in the northern part of their range in Canada tend to breed first in late May and June. A second, more widespread, nesting period occurs from July to September in the southern part of their range. Some of the northern breeders may move south after breeding and join the southern breeding populations and, if conditions are right, may re-nest. This breeding system is probably adapted to delay the timing of nesting to coincide with the preferred habitat conditions of moist, but unflooded meadows or sedge areas. During some years, if habitat conditions are not suitable, Sedge Wrens will not nest in an area, but will return the follow year and nest if the conditions have improved.

Sedge Wrens are wary and rarely noticed unless singing. When flushed, Sedge Wrens usually flutter a short distance, quickly land and run along the ground to evade intruders. As a result of their secretive behavior, little is known about Sedge Wren breeding habits. Both sexes typically have multiple mates. Adults may sabotage nesting competitors; using their sharp bills to pierce the eggs of other Sedge Wrens or other bird species nesting nearby.

Reference(s)

Herkert, J. R., D. E. Kroodsma and J. P. Gibbs. 2001. Sedge Wren (Cistothorus platensis), The Birds of North America Online, . A. Poole, Ed. Ithaca: Cornell Laboratory of Ornithology; Retrieved from The Birds of North America Online database: http://bna.birds.cornell.edu/bna/species/582