Bird populations in Montana linear riparian habitats over 40 years.
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Transcript of Bird populations in Montana linear riparian habitats over 40 years.
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.