Monitoring the Migrants:

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Monitoring the Migrants
From the Net to the Web with Northern Saw-whet
owls
Drew Jones Center for Environmental
Studies Williams College
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Size - among the smallest owls in
North America
Northern Saw-whet Owl (Aegolius acadicus)

• 75-110 grams
• 7-8 inches
• Sexually dimorphic

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Diet

• Small mammals
• mice, shrews,
• voles
• Amphibians
• Insects
• Other songbirds, bats, flying squirrels
• Caching has been noted

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Range of NSWO
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Habitat - Varies throughout range and season-

• Conifers
• Hardwoodscavities
• Shrubs
• Moist, swampy lowlands
• Edges
• Mountains in South

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ProjectOwlNet.orgAd-hoc organization of saw-whet
owl banders throughout N. America

• Dave Brinker, Maryland
• Kathy Duffy, New Jersey
• Tom Erdman, Wisconsin (Mentor)
• Multitude of newcomers (100) in many states and
  provinces
• 1990s

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http//www.projectowlnet.org/index.htm
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Project Owlnet
Support expansion of a network of migrant owl
banding stations Advocate the use of relatively
comparable netting protocols Improve
communication and coordination between owl
banding stations in the North America
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Hopkins Memorial ForestWilliamstown, Mass

• 2600 acres
• 600-2400 feet elevation
• Northern Hardwood Forest
• A few hemlock groves and pine, spruce plantations

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Massachusetts Stations
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Net Location
lat 42 43' 20" long 73 13' 30 elev 825'
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Net Site

• Habitat
• Former poplar plantation with mixed successional
  hardwoods and dense honeysuckle thickets poorly
  drained
• Net Lane
• Old road, path

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Protocol HMF Station

• Single line mist-net array
• Audio Lure two opposable speakers, continuous
  play, courtship call.
• Hours avg. 6 hrs, starting ½ hr. after sunset.
• Oct 1st through Mid-Nov.

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Net Array

• 4 - 12x2.6 meter mist-nets
• Single tier
• 61mm thrush nets

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Audio Lure(classic design, circa 1990s)
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Banding
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Weight
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Measuring Wing Chord
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Checking Feather Wear
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Under UV Light
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Brinker 1997
Developed by Dave Brinker
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Tail Length
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Bill Lengthand Color
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Checking Fat Deposits and Body Condition
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Eye Color
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Variables of Interest

• Overall Population
• Trends
• Age structure
• Longevity, Survivorship
• Morphology
• Migration
• Age/spatial patterns
• Time effects on age/sex
• Weather effects
• Moon phase effects
• Habitat Use/resource correlation

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Saw-whet Owls Banded 1990-2004 U.S. and Canada
Fifteen year estimated total 90,400
Compiled by Strickland Wheelock
Source
US Bird Banding Lab
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Capture Summary 2001-08Hopkins Forest

• 2001 86 (abbreviated season) 26 nights
• 2002 159 plus one EASO 35 nights
• 2003 148 37 nights
• 2004 87 38 nights
• 2005 21 (abbreviated) 10 nights
• 2006 160 42 nights
• 2007 161 (plus one BDOW) 37 nights
• 2008 224 41 nights
• Total 1046 NSWO
• Including 31 banded recaptures from other
  stations (2.96 percent)
• 16 HMF banded owls known to be recaptured
  elsewhere (through 07)

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Migration Timing 2006 vs. 2007
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Demographics
Age Structure
Sex Ratio
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Age Structure Trends
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Age of Recaptures through 2006

• 2 first years
• 7 second years (1.5 yr)
• 10 third year (2.5yr) or older
• 5 fourth years (3.5yr)
• 2 fifth years (4.5 yr)
• 3 sixth years (5.5 yr)

Minimum age for older birds some years of
hatching unknown.
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Re-capture Locations (with distance estimates)

• From
• Huntsdale, PA 278 (2)
• Bittinger, MD 385 (2)
• Burkittsville, MD 315 (2)
• Bergton, VA 404
• Port Rowan, ON 360 (2)
• Falmouth, ME 168 (2)
• Carsonville, PA 238
• New Paltz, NY 78 (2)
• Friedensburg, PA 212
• Ville Marie, QB 428
• Prince Edward Pt, ON 208 (2)
• Brockway, PA 310
• Unknown (2)
• Mean 272

• To
• Tilton, NH, 97
• Assateague, Island, MD 335
• Fulks Run, VA 408
• Snake Mountain, VT 94
• Waasis, NB 394
• Booths Harbour, ON 208 (2)
• Northbridge, MA 95 (2)
• Port Rowan, ON 360
• New Paltz, NY 78 (2)
• Valhalla, NY 118
• Lower Delmarva, VA 403
• Friedensburg, PA 212
• Lynchburg, VA 450
• Mean 221

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Total Recaptures 2002-07 (plus two unknown)
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Direct Recaptures Northbridge, Mass. Oct 13 to
Oct 28, 2004 Oct 21 to Nov 14, 2006
95 miles ESE 15 days 6.3 miles/day 24 days
4.0 miles/day
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Direct Recapture Valhalla, NY Oct 7, 2007 to Oct
29, 2007
118 miles SSW 22 days 5.4 miles/day
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Direct Recapture Assateague Island, MD Nov 3 to
Nov 12, 2004
335 miles SSW 9 days 37 miles/day
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Direct Recaptures Prince Edward Point, ON Oct.
12, 2004 to Nov. 7, 2004 Oct. 20, 2006 to Nov. 2,
2006
205 miles ESE 26 days 7.9 miles/day 13 days 15.8
miles/day
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Direct Recapture Ville Marie, QB Oct 4 to Oct
30, 2006
428 mi SE 26 days 16.5 miles per day
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Direct Recapture New Paltz, NY Oct 21 to Oct 23
2006
Direct Recaptures
New Paltz to HMF 95 mi. 48 hrs. 47
mi/day HMF to Uxbridge 110 mi. 10/21 -11/14
2006 24 days
78 miles NE/SW 2 days (2) 39 miles/day 10
days 7.8 miles/day
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Information Sources(primarily for researchers)

• Project Owlnet (public) http//www.projectowlnet
  .org/default.htm
• Sawwhetnet (membership required)
• http//pets.groups.yahoo.com/group/sawwhetnet
• list-serve
• Yahoo Group site

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Individual Banding StationsPublic

• Prince Edward Point, ON
• http//www.peptbo.ca/
• Whitefish Point, MI
• http//www.wpbo.org/Research.html

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Clearing Houses

• Avian Knowledge Network
• http//www.avianknowledge.net/content
• Canada Naturewatch
• http//www.bsc-eoc.org/birdmon/default/main.jsp

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Breeding Bird InformationSo where do they come
from?
Breeding Bird Surveys http//www.mbr-pwrc.usgs.gov
/bbs/bbs.html Breeding Bird Atlas (state
based) http//www.pwrc.usgs.gov/bba/index.cfm http
//bird.atlasing.org/
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Winter Where do they go?

• Christmas Bird Counts Audubon
• http//www.audubon.org/bird/cbc

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Raptor Migration
Hawkwatch http//hawkcount.org
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Canada

• Bird Studies Canada
• http//www.bsc-eoc.org/
• Canadian Migration Monitoring Network
• http//www.bsc-eoc.org/volunteer/cmmn/index.jsp?ta
  rgetpgindexlangen
• Naturewatch (Monitoring)
• http//www.bsc-eoc.org/birdmon/default/main.jsp

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General

• E-Bird -- CLO
• http//ebird.org/content/ebird

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Get involved with a banding project in your area
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• Hawk Mountain (PA)
• http//www.hawkmountain.org/index.php?prRaptor_Mi
  gration
• Hawk Ridge (MN)
• McGill

Prce Edward Point, ON http//www.peptbo.ca/ White
fish Point, MI http//www.wpbo.org/Research.html
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Celestial Effects

• High capture nights tend to correlate with little
  or no moonlight.
• Presence of stars, however, appears to be
  important.

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Weather Effects
Cool, clear evenings Calm or light
winds (N/NW) After cold
fronts Rain, fog, wind (E, S)
not good
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Sex Rations Individual Years
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Schmitty
0844-43-513 and Schmitty
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Banding