Use of small streams and forest gaps for breeding habitats by winter wrens in Coastal British Columbia

Few studies have examined the value of riparian areas adjacent to streams <=10-m wide as habitat for forest birds. In mature (80-120 years) and young (40-60 years) coastal forests of southern British Columbia, Canada, we examined the habitat values for male winter wrens [Troglodytes troglodytes] of riparian areas adjacent to small streams and areas upslope of these streams. In both riparian and upslope areas, wrens preferentially located nests (n=47) and song perches (n=77) in disturbed sites with fewer trees than randomly located sites. Hydrological processes associated with streams, mortality of dominant canopy trees or uprooted trees can produce these disturbed sites. In mature forest, winter wrens chose stream banks and upturned root masses when available for building their nests with most nest substrates located within 5 m of small streams. In both young and mature forests, they also chose areas near small streams as locations for song perches. Winter wrens may use areas closer to streams when available because channel morphology, the associated heterogeneous forest structure, and microclimate likely provide optimal nesting and foraging habitat. Our research supports operational efforts by forest managers to conserve structures near small streams and in upslope areas because these structures maintain long-term habitat values for wildlife such as winter wrens.Waterhouse et al "Use of small streams and forest gaps for breeding habitats by winter wrens in Coastal British Columbia." Northwest Science. 2002; 76(4): 335-34