ENVIRONMENTAL CONSEQUENCES in rocky mountain coniferous ...

Pileated Woodpeckers on the CEF nested only in western larch and only in stands
with an old-growth component of larch and Douglas-fir. One nest was on the edge of
the lower shelterwood unit. Common Flicker, Mountain and Black-capped Chickadee and
Red-breasted Nuthatch nests were found in stubs left in cutting units. Yellow-
bellied Sapsuckers occasionally nested in paper birch left in she1 terwood units or
even in clearcuts.
The cutting units involved in this study were relatively small; the effects on
overall nesting populations appeared to be minor because of an abundance of old-
growth forest left between and adjacent to the cutting units. Shelterwood units ini-
tially continued to provide both nesting and feeding sites for many birds, but when
the remaining large trees are removed (10-20 years after the first cutting) such
units will lose their usefulness to species that need a denser canopy or large trees.
In cutting units where few snags and stubs were left, the availability of
hole-nest sites probably was a limiting factor for some hole nesters. In uncut
western larch/Douglas-fir forests, food rather than nest sites is probably the
1 imiting factor for woodpeckers. On any unit where timber harvesting tends to el im-
inate western larch larger than 20 in (51 cm) dbh, and other snags and cull s, the
impact on cavity nesters will be strongly negative.
Feeding Activities
During 1977 and 1978, control units and logged units (3 and 4 years after har-
vesting) on the CEF were observed for a total of 569 hours, a minimum of 60 hours in
each unit. The following woodpecker species were observed feeding: Pi1 eated , Hairy,
Downy, and Northern Three-toed Woodpeckers, Common Flicker, and Yellow-bellied and
Nil 1 iamson's Sapsuckers. In general, feeding activity was greater in the lower units
than in the higher units and greater in the control (uncut) units than in the har-
vested units (table 6). The absence of paper birch in the higher units may account
in part for the reduced feeding on those sites. Yellow-bellied Sapsuckers feed
heavily on birch sap during the summer months. Overall feeding activity was slightly
1 ess in the summer of 1978 (1.9%) than in the summer of 1977 (1.6%). Conner and
Crawford (1974) found a much higher percentage of activity in Appalachian clearcuts.
They recorded woodpecker feeding time of 55%, 43%, and 9% o f sampling time in clear-
cuts 1-year old, 5-years old, and 12-years old respectively. However, they also
included activities such as preening and courtship.
TABLE 6. Percent of samplinq time that woodpeckers were observed feeding in lower
and higher treatment units.
Harvesting Treatment
Group Sel ection All units
Treatment elevation Control Uncut Islands Cut She1 terwood Cl earcut Combined
Lower 4300 ft (131 1 m) 6.9 2.7 0.1 5.9 0.1 3.5
Higher 5030 ft (1534 m) 4.4 2.6 -0- 1.3 -0- 1.4
Both 5.g1 2.7 0.1 3.7 0.1 2.5
'Not the mean between lower and higher units because of unequal total observa-
tion times,