Bird use of Delaware wetlands during fall migration based ... · PDF fileBird use of Delaware...
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Bird use of Delaware wetlands during fall migration based on weather radar observations Jeffrey J. Buler 1 , Tim D. Schreckengost 1 , Jaclyn Smolinsky 1 , James McLaren 1 , Deanna K. Dawson 2 , Eric L. Walters 3 1 Dept. of Entomology and Wildlife Ecology 2 Patuxent Wildlife Research Center 3 Dept. of Biological Sciences
Transcript of Bird use of Delaware wetlands during fall migration based ... · PDF fileBird use of Delaware...
Bird use of Delaware wetlands during fall migration based on weather radar observations
Jeffrey J. Buler1, Tim D. Schreckengost1, Jaclyn Smolinsky1, James McLaren1, Deanna K. Dawson2, Eric L. Walters3
1 Dept. of Entomology and Wildlife Ecology
2 Patuxent Wildlife Research Center
3 Dept. of Biological Sciences
WSR-88D Weather Surveillance Radar – 1988 Doppler
(a.k.a. NEXRAD)
Initiation of nocturnal migration
Onset of migration
From Diehl and Larkin 2005
Reflectivity (Z or cm2/km3) (relative bird density)
Radial Velocity (m/s)
Sample volume Tilt = 0.5°
360° rotation
WSR-88D operation and data products
Temporal sampling rate 5 – 10 minutes
Volume scan
Low High
Bird layer
Range from radar (km)
2 – Height distribution of birds (Where are the birds?)
Height distribution of birds
Prop
ortio
n of
bird
s det
ecte
d
1.0
0.8
0.6
0.4
0.2
0.0
1 – Beam propagation (Where is the beam?)
Adjustment for range bias
0 5 10
Buler & Diehl. 2009. IEEE Trans. Geosci. Remote Sens.
Exlcude data if <10% of
distribution sampled
Buler & Dawson (2014)
Autumn (2008 & 2009)
Pooled Autumns 2008 – 2014 (n = 91 days)
Pooled Autumns 2008 – 2014 (n = 91 days)
0.0
0.2
0.4
0.6
0.8
1.0
1.2
1.4
1.6
1.8
2.0
Forest Forestedwetland
Developed Agriculture Marsh
Mea
n bi
rd d
ensit
y (c
m2
/hec
tare
) Bird density among habitat types
9,841 5,310 1,920 38,036 4,428
Annual trend (cm2/ha per year)
Trend in migrant use from 2008 - 2014
Annual trend (cm2/ha per year)
Trend in migrant use from 2008 - 2014
2014 2008 2012
Prim
Annual trend (cm2/ha per year)
Declining bird use on Prime Hook NWR
LANDSAT SWIR Band
0.0
0.2
0.4
0.6
0.8
1.0
1.2
1.4
1.6
2008 2009 2010 2011 2012 2013 2014
Stan
dard
ized
bird
den
sity
Irene 8/28/11
Sandy 10/31/12
Areas of declining bird use at Prime Hook NWR
Photo: Michael Menefee
Wintering waterfowl feeding flight
“Raw” waterfowl exodus 1/1/2016
Reflectivity (dbZ)
Change in bird density over 13 year period (1995 – 2007)
Change in wetness index over years
Steep decrease
Steep increase
No change
From Buler et al. (2012) Sacramento Valley of California
∆ wetness
RegressionCoefficient (Std Dev)
< -2
-2 - -1
-1 - 1
1 - 2
> 2
∆ bird density
5 km From Buler et al. (2012)
Acknowledgements
• Barry Truitt, The Nature Conservancy
Undergraduate students Matt Levendosky
Janine Antalffy Lauren Cruz Laura Young
