FIRE EFFECTS AND USE
WILDLIFE SPECIES: Sialia currucoides | Mountain Bluebird 



DIRECT FIRE EFFECTS ON ANIMALS : 
There are no reports of mountain bluebird mortality due to fire.  Nests
and nestlings are probably vulnerable to severe fire.  Nesting cavities
may be lost in severe fires including crown fires.


HABITAT RELATED FIRE EFFECTS : 
Mountain bluebirds are strongly attracted to early postfire (1-2 years)
communities, particularly those with many standing dead trees.
Woodpecker activity in these communities provides many nest cavities
[32].  Fire initiates a tree-hole nesting cycle in Grand Teton and
Yellowstone National Parks.  Woodpeckers concentrate in newly burned
areas to feed on insects (particularly bark beetles) and to nest in
standing dead trees [62], especially those with decay prior to fire
[50].  Mountain bluebirds and other secondary cavity nesters use the
holes after the woodpeckers abandon them.  In northern Wyoming, northern
three-toed woodpeckers (Picoides tridactylus) and black-backed
three-toed woodpeckers (P. arcticus) begin leaving burned areas about 4
to 5 years after the fire.  Hairy woodpeckers (P. villosus) continue to
excavate holes for years, until snags finally decay to the point of
falling down.  At around 50 postfire years, tree-hole nesting species
usually leave the area even if a few snags are still present [62].

A 1982 study in the Little Firehole River watershed within Yellowstone
National Park indicated that mountain bluebirds were only common in a
222 acre (90 ha) area that burned in 1949.  The authors speculated that
mountain bluebird numbers were high in the late 1700's and early 1800's
because up to 50 percent of the area was covered by early postfire
stands; as forests matured into the twentieth century mountain bluebird
numbers probably decreased [48].  In other areas of Yellowstone National
Park, mountain bluebirds were observed in burned areas in the first
postfire year [22].  Mountain bluebirds were associated with postfire
plots in severely burned lodgepole pine stands in Yellowstone National
Park.  By the second postfire year mountain bluebirds were nesting in
holes excavated by northern three-toed woodpeckers.  Peak mountain
bluebird breeding density occurred on 12-postfire year plots with a
small peak on 30-year-old plots.  There were no mountain bluebirds on
57-year-old and older plots [62].  In Grand Teton National Park,
mountain bluebirds were present in the first postfire year on severely
burned plots, increasing to 15 pairs per 100 acres (15/40 ha) in the
second year.  They were not observed on moderately burned or unburned
plots, or on 43-year-old burned plots [62].

In Alberta fire-originated forests dominated by quaking aspen, balsam
poplar (Populus balsamea), and lodgepole pine, mountain bluebirds were
present in 14-year-old stands but not present in stands that had been
clearcut, nor in 30-, 60-, or 80-year-old stands [66].  In Montana mountain
bluebirds increased from postfire year 2 to postfire year 4 in both
burned and burned and logged areas [24].

In California mountain bluebirds were observed in large numbers (15.2
pairs per 100 acres [15.2/40 ha]) in postfire years 5, 6, and 7 in mixed
coniferous forest.  Woodpecker activity was decreasing by the time of
the study [10].  In the Sierra Nevada a severe fire occurred in a
Jeffrey pine (Pinus jeffreyi)-white fir community in 1960.  Birds were
censused in 1968 and 1975.  Mountain bluebird densities were highest on
burned plots with standing dead trees and openings in 1968.  They were
still present on burned plots in 1975; these plots had developed dense
brushfields [11].

Later postfire communities may not be as attractive as early
successional stages; Raphael and others [47] noted a decreasing trend
for mountain bluebirds in burned habitat in the Sierra Nevada between
1966 and 1985.  In Yellowstone National Park mountain bluebirds
densities 5 to 25 years after fire depend on the number of standing
snags.  At 25 to 30 postfire years mountain bluebird numbers may begin
to decline depending on the rate of snag loss.  From 30 to 50 postfire
years mountain bluebirds depart as canopy closure develops [63].

Based on data from Brawn and Balda [13], Hejl [26] hypothesized a
mountain bluebird population decrease in southwestern ponderosa pine
due to fire exclusion and consequent closure of forests.


FIRE USE : 
Savannas and open stands of mature pine are natural mountain bluebird
habitats that require recurrent fire for maintenance.  Prescribed fire
is usually beneficial to mountain bluebirds, especially if it controls
shrubs and understory trees [45].  Mountain bluebird densities 5 to 25
postfire years depend on the number of standing snags with nest cavities
[63].  In Wyoming, mountain big sagebrush (Artemisia tridentata var.
vaseyana) communities, bordered by Douglas-fir and quaking aspen stands,
were burned with both spring and fall prescribed fires (not on the same
plots).  Mountain bluebirds were present as nonbreeders at higher
densities on the burned plots than on unburned plots (both treatments)
[41].  In Nevada pinyon-juniper woodlands burned with prescribed fire
for 3 consecutive years, mountain bluebird populations were the same on
burned and unburned plots in the first postfire year, but were higher on
burned plots in the second year.  Nest cavities were lost to the fire
the first year, but by the second season cavity numbers were increasing
[38].

Some bird species are eliminated from burned areas, but other species
are attracted to them, creating a similar amount of species diversity
[17].  Prescribed fire in Wind Cave National Park, South Dakota,
temporarily improved foraging habitat for mountain bluebirds by reducing
surface cover.  There was little change in overall tree and snag density
on these sites [12].  Burned areas less than 5 years old, particularly
those that had severely burned, are highly valuable for many cavity
nesting species including mountain bluebirds [62].  For enhancement of
wildlife habitat it is strongly recommended that severely burned areas
be allowed to develop naturally rather than be subject to salvage
logging.  When salvage is considered essential (for sanitary reasons or
as a firebreak), it is recommended that a substantial area be left uncut
rather than thinning the entire burn [32].


REFERENCES : 
NO-ENTRY

Related categories for Wildlife Species: Sialia currucoides | Mountain Bluebird