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Bird populations in Montana linear riparian habitats over 40 years.
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Graduate Student Research: unintended consequences & opportunities
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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
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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
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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
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Hammond’s Flycatcher (Fig 1) MacGillivray’s Warbler Swainson’s Thrush American Redstart Warbling Vireo 5 species of Neotropical migrants
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Elk Creek: typical of lower third of study area
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Elk Creek: typical structure of upper portion
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Stinkwater Creek, 2008; enters lower Elk Creek near Beginning of survey route.
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North Fork: lower portion near confluence with Elk Creek
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North Fork: upper portion of study area
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:North Fork :wolf scat
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“Chunka” 1967, 1968 “Raven” 2008 “Bearpaw” 1980
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Oh to be 25 again!
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In the beginning…, there was snow
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Important Historical Information North Fork harvested in 1927-28 Major stand replacement fire in 1930 Removal of cattle grazing in 1982.
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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
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JanuaryFebruary 1989 Leaf bud emergence Leaf buds killed
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1980 2008 North Fork study area
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Table. Characteristics of the live and dead mountain alder component of three riparian habitats in western Montana. North ForkElk CreekStinkwater Cr. MeanSEMeanSEMeanSE Live 1-5 cm70.28.447.78.9133.8 6 -10 cm29.44.911.72.55.91.4 11-20 cm62.13.51.510.4 20+ cm0.70.30.1 00 Dead 1-5 cm00.4 0 6 -10 cm2.11.32.40.60 11-20 cm2.90.92.60.60.30.2 20+ cm3.20.81.60.60
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1 2 3 4
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The cattle are gone, but….
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Table. Frequency of occurrence of characteristic plants of three riparian areas. Species North 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 Douglas-fir, Pseudotsuga menziesii.05.10.66.27 Engelmann spruce, Picea engelmannii.36.030.13 Highbush cranberry, Viburnum,edule 0.01.28.10
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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
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Species1968198020081968-2008 Winter Wren7.0013.0+6.0 Song Sparrow2.006.0+4.0 Hammond’s Flycatcher9.510.05.0-4.5 Warbling Vireo6.0 0-6.0 MacGillivray’s Warbler9.514.59.0-0.5 American Redstart12.500-12.5 Lincoln’s Sparrow002.0+2.0 Total46.530.535.0-11.5 Table. Number of territories between 1968-2008 among selected bird species along the North Fork of Elk Creek.
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Species198020081968-2008 Winter Wren06.0+6.0 Song Sparrow3.07.0+4.0 Hammond’s Flycatcher13.515.5+2.0 Warbling Vireo12.09.0-3.0 MacGillivray’s Warbler13.016.0+6.0 American Redstart19.02.0-17.0 Veery80-8.0 Total68.555.5-13.0 Table. Number of territories between 1980-2008 among selected bird species along Elk Creek.
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I had visitors
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Approximate territory boundaries for MacGillivray’s Warbler on a portion of the North Fork, 2008. Red indicates date of singing male observation.
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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
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Territory Establishment for MacGillivray’s Warbler along the North Fork of Elk Creek, 1968,1980 and 2008
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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
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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)
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Territory Establishment for the MacGillivray’s Warbler in three riparian areas, western Montana, 2008
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Territory Establishment for Hammond’s Flycatcher along Elk Creek, 1980 and 2008
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Territory Establishment for the Hammond’s Flycatcher in three riparian areas, western Montana, 2008
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Territory Establishment for Warbling Vireo along the North Fork of Elk Creek, 1968,1980 and 2008
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June Snow: mortality of Neotropical migrants
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Swainson’s Thrush
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Chipping Sparrow
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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.
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