Bird populations in Montana linear riparian habitats over 40 years.

Graduate Student Research: unintended consequences &

opportunities

• Original study in 1967 and 1968 on the North Fork of Elk Creek

• A second study in 1980 added Elk Creek for comparison

• In 2008, Stinkwater Creek added

Habitat Selection & Territory Establishment

Habitat selection: follows a hierarchical decision-making process (Hutto 1985) involving innate and learned behaviorial decisions made by an animal about where it should be at different scales of the environment.

Habitat preference: is restricted to the consequence of the habitat selection process , resulting in the disproportionate use of some resources over others.

Territory: a defended area

Habitat Selection & Territory Establishment

This study involved:

1. determining the chronological pattern of territory establishment of 5 species of Neotropical migrants along 3 riparian areas

2. Delineating territory boundaries

3. Testing whether the earliest arrivals selected different habitat than later arrivals

Hammond’s Flycatcher (Fig 1)

MacGillivray’s Warbler

Swainson’s Thrush

American Redstart

Warbling Vireo

5 species of Neotropical migrants

Elk Creek: typical of lower third of study area

Elk Creek: typical structure of upper portion

Stinkwater Creek, 2008; enters lower Elk Creek near Beginning of survey route.

North Fork: lower portion near confluence with Elk Creek

North Fork: upper portion of study area

:North Fork :wolf scat

“Chunka” 1967,1968

“Raven” 2008

“Bearpaw” 1980

Oh to be 25 again!

In the beginning…, there was snow

Important Historical Information

• North Fork harvested in 1927-28• Major stand replacement fire in 1930• Removal of cattle grazing in 1982.

What has changed in 40 years?

• Decline and re-birth of mountain alder

- Mortality in Feb., 1989– Loss of canopy height and density– Increase in small diameter saplings

• Encroachment of conifers• Cattle grazing pressure partly

replaced by elk and deer browzing

-36

-31

-26

-21

-16

-11

-6

-1

4

9

14

19

24

20 21 22 23 24 25 26 27 28 29 30 31 1 2 3 4 5 6 7 8 9 10 11 12 13

Max TempMin Temp

January February

1989

Leaf bud emergence

Leaf buds killed

1980

2008

North Fork study area

Table . Characteristics of the live and dead mountain alder component of three riparian habitats in western Montana.

North Fork Elk Creek Stinkwater Cr.

Mean

SE Mean

SE Mean

SE

Live

1-5 cm 70.2 8.4 47.7 8.9 13 3.8

6 -10 cm 29.4 4.9 11.7 2.5 5.9 1.4

11-20 cm 6 2.1 3.5 1.5 1 0.4

20+ cm 0.7 0.3 0.1 0.1 0 0

Dead

1-5 cm 0 0.4 0.4 0

6 -10 cm 2.1 1.3 2.4 0.6 0

11-20 cm 2.9 0.9 2.6 0.6 0.3 0.2

20+ cm 3.2 0.8 1.6 0.6 0

1

2

3

4

The cattle are gone, but….

Table . Frequency of occurrence of characteristic plants of three riparian areas.

SpeciesNorth Fork

Elk Creek

Stinkwater Cr.

Overall mean

Mountain alder, Alnus tenuifolia

.98 .96 .77 .90

Red-osier dogwood, Cornus stolonifera

.88 .93 .70 .84

Common Snowberry, Symphoricarpus albus

.57 .16 .70 .48

Douglas maple, Acer glabrum

.01 .30 .79 .37

Prickly rose, Rosa aciculars

.04 .02 .04 .34

Northern black currant, Ribes hudsonianum

.70 .03 .30 .30

Douglas-fir, Pseudotsuga menziesii

.05 .10 .66 .27

Engelmann spruce, Picea engelmannii

.36 .03 0 .13

Highbush cranberry, Viburnum,edule

0 .01 .28 .10

Field Methods for Birds

• Surveyed birds by mapping territories of singing males•Number of surveys:• Elk Creek- 1980: 14; 2008:31• North Fork: 1968:17; 1980:14; 2008:33• Stinkwater Creek: 2008:13

Species 1968 1980 2008 1968-2008

Winter Wren 7.0 0 13.0 +6.0

Song Sparrow 2.0 0 6.0 +4.0

Hammond’s Flycatcher 9.5 10.0 5.0 -4.5

Warbling Vireo 6.0 6.0 0 -6.0

MacGillivray’s Warbler 9.5 14.5 9.0 -0.5

American Redstart 12.5 0 0 -12.5

Lincoln’s Sparrow 0 0 2.0 +2.0

Total 46.5 30.5 35.0 -11.5

Table . Number of territories between 1968-2008 among selected bird species along the North Fork of Elk Creek.

Species 1980 2008 1968-2008

Winter Wren 0 6.0 +6.0

Song Sparrow 3.0 7.0 +4.0

Hammond’s Flycatcher 13.5 15.5 +2.0

Warbling Vireo 12.0 9.0 -3.0

MacGillivray’s Warbler 13.0 16.0 +6.0

American Redstart 19.0 2.0 -17.0

Veery 8 0 -8.0

Total 68.5 55.5 -13.0

Table . Number of territories between 1980-2008 among selected bird species along Elk Creek.

I had visitors

Approximate territory boundaries for MacGillivray’s Warbler on a portionof the North Fork, 2008. Red indicates date of singing male observation.

Habitat Selection & Territory Establishment

Habitat selection: follows a hierarchical decision-making process (Hutto 1985) involving innate and learned behaviorial decisions made by an animal about where it should be at different scales of the environment.

Habitat preference: is restricted to the consequence of the habitat selection process , resulting in the disproportionate use of some resources over others.

Territory: a defended area

Territory Establishment for MacGillivray’s Warbler along the North Fork of Elk Creek,

1968,1980 and 2008

0

5

10

15

20

1 3 5 7 9 11 13 15 17 19 21 23 25 27 29 31 1 3 5

May and J une

Cum

ulat

ive N

o. o

f T

err

itor

ies 2008

1980

1968

•Did early arriving MacGillivray’s Warblers select territories that were different with respect to certain

veg characteristics along the North Fork?

• Veg parameters measured & tested:• Riparian width• Canopy cover of alder• Canopy cover of dogwood• Canopy cover of conifers• Canopy cover of Ribes• Canopy cover of snowberry• Height of alder• Height of dogwood

• ANSWER: NO

•Did early arriving MacGillivray’s Warblers select territories that were different with respect to certain

veg characteristics along Elk Creek?

ANSWER: yes

• Riparian width (t = 6.12, P <0.0001)

• Alder height (t = 2.11, P = 0.04)

• Snowberry can. cover (t = 1.65, P = 0.10)

Territory Establishment for the MacGillivray’s Warbler in three riparian

areas, western Montana, 2008

0

2

4

6

8

10

12

14

16

18

1 3 5 7 9 11 13 15 17 19 21 23 25 27 29 31 2 4 6 8

May and J une

Cum

ulat

ive

No.

of

Ter

rito

ries

Elk Creek

North Fork

Stinkwater

Territory Establishment for Hammond’s Flycatcher along Elk Creek, 1980 and 2008

0

5

10

15

20

25

30

35

1 3 5 7 9 11 13 15 17 19 21 23 25 27 29 31

May

Cum

ulat

ive

No.

of

Ter

rito

ries 2008

1980

Territory Establishment for the Hammond’s Flycatcher in three riparian areas, western

Montana, 2008

0

5

10

15

20

25

30

35

1 5 9 13 17 21 25 29 2 6 9

May and J une

Cum

ulat

ive

No.

of

Ter

rito

ries

Elk Creek

North Fork

Stinkwater

Territory Establishment for Warbling Vireo along the North Fork of Elk Creek, 1968,1980

and 2008

0

2

4

6

8

10

12

14

16

18

1 3 5 7 9 11 13 15 17 19 21 23 25 27 29 31 1 3 5 7 9

May and J une

Cum

ulat

ive

No.

of

Ter

rito

ries

2008

1980

1968

June Snow: mortality of Neotropical migrants

Swainson’s Thrush

Chipping Sparrow

Summary• Mountain alder mortality in 1989 impacted

some birds since then

• Several species increased over time, some decreased, and some changed little

• the Veery, Red-eyed Vireo, and American Redstart either disappeared or were greatly reduced in 2008

• Early arriving males did, in some cases, select habitat different in some attributes than later arriving males.