USDA Forest Service Research Note RMRS-RN-16. 2002 1

Bird Counts of Burned

Versus Unburned Big

Sagebrush Sites

Bruce L. Welch

Abstract—Burned-over big sagebrush sites dominated by perennial grasses supported fewer species of birds and fewer total number

of birds than sites of unburned big sagebrush sites.

Keywords: fire effects, neotropical migrants, Artemisia tridentata

Introduction ____________________

During a big sagebrush Y2K odyssey through the States of

Idaho, Oregon, and Washington, I came across a valley

perhaps 1,000 acres in size located approximately 13 miles

north by northeast of Grasmere, ID (fig. 1). Three things

were obvious about this valley: (1) it had burned in the recent

past, (2) before burning it was covered with a stand of

Wyoming big sagebrush (Artemisia tridentata ssp.

wyomingensis), and (3) it had been reseeded with a mixture

of perennial grasses and forbs—mostly nonnative. Cheatgrass (Bromus tectorum) dominated rocky terrain and steep

hillsides where seeding had not occurred (fig. 1). I walked

through the valley to see if I could find Wyoming big sagebrush seedlings to get an idea on how fast Wyoming big

sagebrush was recovering. With a Global Positioning System (GPS) unit in hand to measure the distance traveled and

a pair of binoculars around my neck (I like to bird watch

when I am out), I started my search for seedlings. After

walking for about one-quarter of a mile, I sensed something

was missing besides Wyoming big sagebrush seedlings.

Walking on for perhaps another 100 ft, I suddenly realized

I had not spotted any birds; at that distance in big sagebrush

I normally would have flushed three or four different species

of birds. My walk in the valley covered 3.6 miles, and in that

distance two horned larks (Eremophila alpestris) were

flushed. On the southern edge of this valley and upslope was

a small (49 x 203 ft) patch of Wyoming big sagebrush. Two

horned larks and three sage sparrows (Amphispiza belli)

were flushed from this small patch. I then formed a hypothesis that burned big sagebrush sites converted to perennial

grass supports fewer birds and fewer species of birds than

unburned big sagebrush sites. To test this hypothesis, I

conducted an experiment.

United States

Department

of Agriculture

Forest Service

Rocky Mountain

Research Station

Research Note

RMRS-RN-16

September 2002

Figure 1—Photo of valley described in text. It had

burned in the recent past. Before burning, it was

covered with a stand of Wyoming big sagebrush (Artemisia tridentata ssp. wyomingensis), and had been

reseeded with a mixture of perennial grasses and

forbs—mostly nonnative. Cheatgrass dominates rocky

terrain and steep hillsides where seeding had not

occurred (see arrows).

Bruce L. Welch is a Research Plant Physiologist with the U.S.

Department of Agriculture, Forest Service, Rocky Mountain Research

Station, Shrub Sciences Laboratory, Provo, UT 84606.

 2 USDA Forest Service Research Note RMRS-RN-16. 2002

Welch Bird Counts of Burned Versus Unburned Big Sagebrush Sites

Materials and Methods ___________

To test my hypothesis, burned big sagebrush sites paralleled with unburned big sagebrush sites were selected as I

traveled through big sagebrush country in the States of

Oregon, Idaho, Utah, Wyoming, and Montana. Oregon data

were collected in 2000, and data from the remaining States

were collected in 2001. Selected sites had to meet the

following criteria: length of bird flushing transect 1 mile,

buffer width 300 ft between the two types of sites (burned

and unburned), burned sites dominated by perennial grasses,

and at least 20 percent canopy cover of big sagebrush on

unburned sites.

Flushing bird counts were conducted between June11and

23 and between the hours of 6:00 and 12:00 a.m. There

appears to be a bias in the study methodology that may favor

bird counts for burned big sagebrush sites. Often birds in

unburned big sagebrush sites were heard but not seen, and

flushing width seemed to be twice as wide as for the unburned big sagebrush transects—meaning birds counts were

lower than actual for the unburned big sagebrush sites.

Paired t-tests were used to detect differences between

burned big sagebrush sites dominated by perennial grasses

and unburned big sagebrush sites for number of bird species

(Hintze 1992). As it turned out, the data for total number of

birds were not normally distributed. A nonparametric test

(a simple sign test) was used for this data set (Conover

1980). Thirteen paired sites were located: two in Oregon,

four in Idaho, three in Utah, two in Wyoming, and two in

Montana. The ages of five burns were known and ranged

from 1 to 14 years (data on file at the Rocky Mountain

Research Station Shrub Sciences Laboratory, 735 N 500 E,

Provo, UT 84606).

Subspecies of big sagebrush was determined by morphological and chemical characteristics (Beetle 1960; Beetle and

Young 1965; McArthur and others 1979). Subspecies represented were: Wyoming big sagebrush—five sites, mountain

big sagebrush (A. t. ssp. vaseyana)—four sites, and basin big

sagebrush (A. t. ssp. tridentata)—four sites.

Results ________________________

Results of bird counts are shown in table 1. The mean

number of bird species found on burned big sagebrush sites

dominated by perennial grasses was 2.23 and on unburned

big sagebrush sites 7.54. These values were found to be

statistically significant at the 5-percent level. Mean total

number of birds found on burned big sagebrush sites dominated by perennial grasses was 7.62, and for unburned big

sagebrush sites, 37.38. These values were statistically significant. Twenty-seven species of birds were identified on

the 13 paired sites. Bird species and their numbers found on

the transects are listed in table 2. Of the 27 bird species, two

species were found only on burned big sagebrush sites:

burrowing owl (Athene cunicularia) and long-billed curlew

(Numenius americanus). Six species were found on both

burned and intact big sagebrush sites: bank swallow (Riparia

riparia), brown-headed cowbird (Molothrus ater), horned

lark (Eremophila alpestris), mourning dove (Zenaida

macroura), vesper sparrow (Pooecetes gramineus), and western

meadowlark (Sturnella neglecta). Nineteen bird species were

found only on unburned big sagebrush sites: American

kestrel (Falco sparverius), American robin (Turdus

migratorius), barn swallow (Hirundo rustica), Brewer’s blackbird (Euphagus cyanocephalus), Brewer’s sparrow (Spizella

breweri), broad-tailed hummingbird (Selasphorus

platycercus), chipping sparrow (Spizella passerina), cliff

swallow (Petrochelidon pyrrhonota), common poorwill

(Phalaenoptilus nuttallii), gray flycatcher (Empidonax

wrightii), greater sage grouse (Centrocercus urophasianus),

green-tailed towhee (Pipilo chlorurus), lark sparrow

(Chondestes grammacus), loggerhead shrike (Lanius

ludovicianus), mountain bluebird (Sialia currucoides), ringnecked pheasant (Phasianus colchicus), sage sparrow

(Amphispiza belli), sage thrasher (Oreoscoptes montanus),

and Swainson’s hawk (Buteo swainsoni).

Observations and Discussion _____

What I thought was a never before described phenomenon, birds being more abundant in big sagebrush stands

than stands of perennial grasses on big sagebrush burnedover sites, turned out not to be. Reynolds and Trost (1980a,b,

1981), studying the impact of crested wheatgrass plantings

on wildlife on the Idaho National Engineering Laboratory

(INEL), found, on what was probably Wyoming big sagebrush sites, that these sites were significantly richer in bird

species than crested wheatgrass (Agropyron desertorum)

sites. Also, the total number of birds was significantly higher

on big sagebrush sites than on created wheatgrass sites.

Wyoming big sagebrush canopy cover for the Reynolds

and Trost (1980a,b, 1981) study sites were 17 and 25 percent. They reported that the density of birds was significantly higher on Wyoming big sagebrush sites with 25

percent canopy cover than on sites with 17 percent cover.

Rotenberry (1980) also found greater numbers of sage sparrow and western meadow lark (Sturnella neglecta) on sites

where Wyoming big sagebrush canopy covers ranged from

25 to 30 percent than for sites with Wyoming big sagebrush

canopy cover of 0 to 1 percent and 5 to 10 percent. These

percentages of canopy cover for Wyoming big sagebrush far

exceeds what the range management community considers

normal or natural (Winward 1991). Perhaps this is best

verbalized by Miller and others (1994):

In the early to mid 1800s, much of the sagebrush steppe

was probably composed of open stands of shrubs with a strong

component of long-lived perennial grasses and forbs in the

understory....Shrub canopy cover probably ranged between 5-

10% in the drier Wyoming big sagebrush (Artemisia tridentata ssp. wyomingensis) communities...to 10-20% on the more

mesic sites, occupied by mountain big sagebrush.

Speaking of the present, they noted that “Wyoming big

sagebrush cover has increased from less than 10% to 20%,

and mountain big sagebrush cover from less than 20% to 30

and 40% ” due to overgrazing. These assertions are challengeable on three fronts (Welch 2002):
USDA Forest Service Research Note RMRS-RN-16. 2002 3

Bird Counts of Burned Versus Unburned Big Sagebrush Sites Welch

Table 1—Bird counts on burned big sagebrush sites dominated by perennial grasses versus unburned big sagebrush sites. Each flushing transect

was 1 mile long and at lest 300 feet from the edge of the burn.

Transect Number of Total Age of

Site number Vegetation bird species birds burn Location

Oregon

 Burns Junction 1 Grass seeding 2 4 ? N 42o 51.547 sna

W 117o 33.959

2 Wyoming big sagebrush 7 44 – N ?

W next to above

New Princeton 3 Grass seeding 2 3 ? N 43o 01.582 sn

W 118o 14.447

4 Basin big sagebrush 8 37 – N ?

W next to above

Idaho

Holbrook 5 Grass seeding 3 10 9 N 42o 12.709' sn

W 112o 35.066'

6 Mountain big sagebrush 11 44 – N 42o 13.510' ns

W 112o 34.795'

 Stone 7 Grass native 2 2 14 b

8 Mountain big sagebrush 5 20 – N 42o 01.856' ew

W 112o 37.521'

INEL 9 Grass native 2 21 5 N 43o 25.490' sn

W 112o 44.571'

10 Wyoming big sagebrush 10 51 – N 43o 26.435' ns

W 112o 43.947'

Strevell 10 Grass seeding 2 6 ? N 41o 59.757' ew

W 113o 11.511'

12 Basin big sagebrush 5 44 – c

Utah

Howell 13 Grass seeding 2 4 ? d

14 Mountain big sagebrush 7 21 – N 41o 48.177' sn

W 112o 22.066'

Vernon 15 Grass seeding 4 15 ? N 40o 08.104' ew

W 112o 29.697'

16 Basin big sagebrush 10 55 – N 40o 07.529' we

W 112o 30.739'

Jericho 17 Grass seeding 2 6 5 N 39o 43.716' sn

W 112o 17.765'

18 Wyoming big sagebrush 6 49 – N 39o 44.329' ns

W 112o 17.111'

Wyoming

Nugget 19 Grass native 4 14 ? N 41o 49.435 ew

W 110o 44.328

20 Wyoming big sagebrush 8 32 – N 41o 49.585 ew

W 110o 45.410

Lander 21 Grass native 2 3 1 N 42o 37.620 ns

W 108o 36.488

22 Mountain big sagebrush 9 46 – N 42o 37.653 sn

W 108o 36.658

Montana

Billings 23 Grass native 1 6 ? N 46o 01.621 we

W 108o 31.814

24 Wyoming big sagebrush 6 15 – N 46o 01.016 we

W 108o

 29.225

 Butte 25 Grass native 1 5 ? N 45o 49.427 we

W 111o 52.263

26 Basin big sagebrush 6 28 – N 45o 14.614 ne-sw

W 1120 53.510

a

Two letter abbreviation denotes direction of bird transect: ns = north to south; sn = south to north; we = west to east; ew = east to west. b

Bird transect was not a straight line but a square shaped “u,” with a starting point at N 42o 01.574'; W 112o 37.521', and going due west for 0.4 mile, then due north

for 0.3 mile, and then due east for 0.3 mile. c

Location of the starting point was not noted, but was in the big sagebrush stand north of the grass seeding, and was traversed east to west. d

Bird transect was not a straight line. Starting point was at N 41o 48.854'; W 112o 22.132', and went 0.4 mile due south, and then 0.2 mile due west, and then 0.4 mile

due south.
4 USDA Forest Service Research Note RMRS-RN-16. 2002

Welch Bird Counts of Burned Versus Unburned Big Sagebrush Sites

Table 2—Bird species and numbers found on the various transects of burned big sagebrush sites dominated by perennial grasses and unburned

big sagebrush sites (common and scientific names by Alsop 2001).

Big sagebrush sites

Burned Unburned

Transect Total number Transect Total number

Common name Scientific name number of birds number of birds

American kestrel Falco sparverius 10 1

18 1

American robin Turdus migratorius 2 1

6 1

14 1

22 1

Bank swallow Riparia riparia 19 2 20 5

Barn swallow Hirundo rustica 8 1

Brewer’s blackbird Euphagus cyanocephalus 14 3

22 8

Brewer’s sparrow Spizella breweri 2 3

4 10

6 9

8 9

10 4

14 6

16 7

18 10

20 4

22 16

24 4

26 4

Broad-tailed hummingbird Selasphorus platycercus 10 2

16 2

Brown-headed cowbird Molothrus ater 6 1

10 1

21 1

Burrowing owl Athene cunicularia 15 2

Cliff swallow Petrochelidon pyrrhonota 10 4

Chipping sparrow Spizella passerina 16 1

Common poorwill Phalaenoptilus nuttallii 4 2

24 1

Gray flycatcher Empidonax wrightii 16 3

20 1

22 1

Greater sage grouse Centrocercus urophasianus 26 4

Green-tailed towhee Pipilo chlorurus 22 4

Horned lark Eremophila alpestris 1 3 29

3 1 47

5 7 62

7 1 83

9 18 10 3

11 4

15 6

17 4 18 2

19 6 20 1

Lark sparrow Chondestes grammacus 14 3

24 2

Loggerhead shrike Lanius ludovicianus 16 1

18 1

(con.)
USDA Forest Service Research Note RMRS-RN-16. 2002 5

Bird Counts of Burned Versus Unburned Big Sagebrush Sites Welch

Table 2—Con.

Big sagebrush sites

Burned Unburned

Transect Total number Transect Total number

Common name Scientific name number of birds number of birds

Long-billed curlew Numenius americanus 15 3

Mountain bluebird Sialia currucoides 12 3

20 1

Mourning dove Zenaida macroura 2 6

4 1

6 6

8 2

10 8

16 2

21 2 22 3

24 1

26 3

Ring-necked pheasant Phasianus colchicus 6 3

16 3

Sage sparrow Amphispiza belli 2 17

4 11

6 9

10 16

12 26

14 2

16 22

18 30

20 10

22 6

26 11

Sage thrasher Oreoscoptes montanus 4 2

6 2

10 6

12 6

14 1

16 3

26 3

Swainson’s hawk Buteo swainsoni 6 1

Vesper sparrow Pooecetes gramineus 1 1 23

3 2 41

5 2 62

12 3

13 1

19 4 20 5

22 3

24 2

26 3

Western meadowlark Sturnella neglecta 2 5

4 3

5 1 68

7 1 85

9 3 10 6

11 2 12 6

13 3 14 5

15 4 16 11

17 2 18 5

19 2 20 5

22 4

23 6 24 5

25 5
6 USDA Forest Service Research Note RMRS-RN-16. 2002

Welch Bird Counts of Burned Versus Unburned Big Sagebrush Sites

1. What do the animals that coevolved with big sagebrush

suggest to us concerning canopy cover?

2. What are the big sagebrush canopy cover values found

in undisturbed relicts and kipukas (older land surrounded

by younger lava flows)?

3. What is the quality of the science that is used to support

these assertions?

It is obvious that burning big sagebrush stands reduces

the biodiversity of the site in terms of bird species and total

number of birds. It is held by many in the range management

community that killing, thinning, or controlling big sagebrush would result in an increase in biodiversity (Olsen and

others 1994). (I have never liked the term “controlling big

sagebrush” because it infers that big sagebrush is out of

control. Who has the ecological insight to determine when

big sagebrush is out of control?) This study does not support

that assertion. In fact, it has been shown that big sagebrush

is a “nursing mother” to a host of organisms ranging from

microscopic to large mammals, and as this study shows,

birds (Welch 2002).

Acknowledgments ______________

The author expresses his appreciation to Dr. Howard B.

Christensen, Dr. Jeffery Kelly, Dr. Rosemary L. Pendleton,

Dr. Nancy L. Shaw, and Dr. Carl L. Wambolt for providing

peer reviews for this manuscript.

References _____________________

Alsop, Fred J., III. 2001. Birds of North America, western region.

New York: DK Publishing. 725 p.

Beetle, A. A. 1960. A study of sagebrush: the section Tridentatae of

Artemisia. Bull. 368. Laramie: University of Wyoming, Agricultural Experiment Station. 83 p.

Beetle, Alan, A.; Young, Alvin. 1965. A third subspecies in the

Artemisia tridentata complex. Rhodora. 67: 405–320.

Conover, W. J. 1980. Practical nonparametric statistics. New York:

John Wiley & Sons.

Hintze, Jerry L. 1992. Number cruncher statistical system. 329 N

1000 E, Kaysville, UT 84037. 442 p.

McArthur, E. Durant; Blauer, A. Clyde; Plummer, A. Perry; Stevens,

Richard. 1979. Characteristics and hybridization of important

intermountain shrubs. III. Sunflower family. Res. Pap. INT-220.

Ogden, UT: U.S. Department of Agriculture, Forest Service,

Intermountain Forest and Range Experiment Station. 82 p.

Miller, Richard F.; Svejcar, Tony J.; West, Neil E. 1994. Implications

of livestock grazing in the Intermountain sagebrush region: plant

composition. In: Vavra, Martin; Laycock, William A.; Pieper, Rex

D., eds. Ecological implications of livestock herbivory in the West.

Denver, CO: Society for Range Management: 101–146.

Olson, Rich; Hansen, John; Whitson, Tom; Johnson, Kris. 1994.

Tebuthiuron to enhance rangeland diversity. Rangelands. 16:

197–201.

Reynolds, Timothy D.; Trost, Charles H. 1980a. The effect of crested

wheatgrass planting on wildlife on the Idaho National Engineering Laboratory site. In: Swanson, Gustav A., tech. coord. Proceedings—the mitigation symposium; 1997 July 16–20; Fort Collins,

CO. Gen. Tech. Rep. RM-65. Fort Collins, CO: U.S. Department of

Agriculture, Forest Service, Rocky Mountain Forest and Range

Experiment Station: 665–666.

Reynolds, Timothy D.; Trost, Charles H. 1980b. The response of

native vertebrate populations to crested wheatgrass planting and

grazing by sheep. Journal of Range Management. 33: 122–125.

Reynolds, Timothy D.; Trost, Charles H. 1981. Grazing, crested

wheatgrass, and bird populations in southeastern Idaho. Northwest Science. 55: 225–234.

Rotenberry, John T. 1980. Dietary relationships among shrubsteppe

passerine birds: competition or opportunism in a variable environment. Ecological Monographs. 50: 93–110.

Welch, Bruce L. 2002. [In press]. Big sagebrush: a sea fragmented

into lakes, puddles, and ponds. Gen. Tech. Rep. RMRS-GTR. Fort

Collins, CO: U.S. Department of Agriculture, Forest Service,

Rocky Mountain Research Station.

Winward, Al H. 1991. A renewed commitment to the management of

sagebrush grasslands. Special Rep. 880. Corvallis: Oregon State

University, Agriculture Experiment Station. 7 p.
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