Mitigation of Woodpecker Damage to Power Poles in British Columbia, Canada

摘要

Wooden utility poles are subject to damage by woodpeckers. Their excavations are thought to ad-vance premature wood decay and often occur near support bracing so as to weaken the structuralintegrity of the pole. On one transmission line in the Caribou region of central British Columbia,14.1% of all poles examined (n = 1,097) sustained various degrees of damage, ranging from super-ficial excavations to multiple 0.6-m deep cavities in one pole. Among the damaged poles, 38.7%(60 poles) contained cavities. The median height of cavities was 8.3 cm with more cavities tendingto occur at or near the lower attachment of the cross brace between adjacent H-frame poles. Dam-aged poles with cavities were aggregated into focal areas along the line as a function of the age andcanopy composition of the surrounding forest. During the breeding season, we located 57 activenest cavities associated with these focal areas both on rights-of-way and in the surrounding forest.Although just over half of these nests (32 = 56%) belonged to woodpeckers comprising 8 differentspecies, none of their nests were found in power poles. Only secondary cavity nesters, includingtree swallow (Tachycineta bicolor) and mountain bluebird (Sialia currocoides), were observed usingcavities in poles for nesting. Examination of a province-wide database on woodpecker damagerevealed that most damage by far was located in the drier IDF (Interior Douglas-fir) zones in thesouthern part of the province. A mitigation strategy to reduce structural damage to poles andassociated maintenance costs might be found in: 1) greater awareness of the habitat potential forwoodpeckers in forest stands adjacent to rights-of-way, 2) adoption of deterrent strategies on sec-tions of right-of-way with woodpecker cavity issues, and 3) relocation of a few damaged poles atstrategic locations along or just outside the right-of-way.