Mitchell et al. • DICKCISSEL NESTLING PROVISIONING 
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Our objective was to quantify provisioning 
activities of Dickcissels (Spiza americana ) using a 
combination of continuous video recording and 
direct observation. We hypothesized that: (1) 
provisioning rates and biomass delivered by 
Dickcissels would increase with nestling age and 
differ between nests in CRP buffers compared to 
nesLs in non-buffer habitats (potentially primary 
habitat); (2) prey size would increase with 
nestling age and nestling number, and differ 
between buffer and non-buffer nests; and (3) 
longer foraging trips would be associated with 
alder nestlings, larger clutches, and larger prey 
sizes. 
METHODS 
Focal Species .—The Dickeissel has declined in 
the United States (trend = -0.7% since 1966: 
Sauer et al, 2011) and is listed by Partners in 
Flight IPIF) as a species of concern in the 
Southeastern Coastal Plain region because of 
anthropogenic threats to breeding habitat (Rich 
si al. 2004). Dickcissels are polygynous and nest 
in fallow fields, unmowed hayfiekls. and old 
fields with abundant forbs (Temple 2002). Nest 
building to hatching lakes 15-21 days, and 
nestlings Hedge after 8-10 days (Temple 2002), 
Dickcissels are mostly granivorous. but feed 
primarily on arthropods during the breeding 
se » s on (Temple 2002). 
Study Area .—We conducted our research at B. 
tartan Farms Inc., a 2,104-ha privately-owned farm 
1:1 C'la) County. Mississippi within the Black 
Fmirie physiographic region. Seventy-nine hect- 
atrfk °1 mw crops had been enrolled in CP33- 
Dabitat Buffers for Upland Birds in 2005. CP33 is 
rot restricted to highly erodible farmland, allow ing 
for wider implementation in intensive agricultural 
landscapes where grassland habitat is often scarce. 
Buffers are composed of 10 to 40-m strips of native 
‘ arrn-season grasses planted around agricultural 
re,d margins to provide habitat for Northern 
Bobwhite (Col inns Virginia mis) and other conti- 
neniallydeclining birds such as Dickeissel. Indigo 
hunting (Passerina cyanea ), and Field Sparrow 
‘Wa-lln pit si l la) (Sauer et al. 2011) that may use 
cp 33 buffers ( e ,g.. Smith et al. 2005). 
• P’3 buffers were planted with big bluestem 
'htdropogon gerardii), little bluestem (Scliiza- 
'’lynum scoparium ), indiangrass (Sorghastrum 
Mans), partridge pea ( Chamaecrista fasciculate). 
b >ack-eyed susan (Rudheckia hirta ), and Maximi- 
l |an sunflower (Helianthus maximiliani) in May 
2004. These buffers were 4 and 5 years post- 
establishment at the time of our study. Producers 
are required to periodically disturb buffers (e.g., 
light disking or prescribed burning), and a subset of 
buffers was burned (in spring) or disked (in fall) 
each year as part of a broader experiment (Adams 
2011. Dollar 2011. Hale et al. 2011). Dickcissels 
largely avoided nesting in disturbed buffers 
(Adams 2011), and we do not address disturbance 
effects. We located Dickeissel nests m areas along 
the periphery or near (<I0 m) CP33 buffers. These 
'non-buffer' habitats were structurally similar to 
old field habitats because of the greater forb. shrub, 
ami sapling components compared to CP33 buffers 
(K. 1.. Baker, unpubl. data). 
Video Monitoring .—We systematically searched 
buffers and surrounding habitats during May, June, 
and July 2008-2009 to locate nests. We video- 
recorded nestling provisioning activity during 
acceptable weather conditions (no rain or sus¬ 
tained winds >16 km/hr) on one to four mornings 
between days 4 and 7 post hatching. We did not 
film before day 4 to avoid nest abandonment by 
parents (Schadd and Ritchison 1998) or after day 7 
to avoid premature Hedging. 
We placed tripods with mounted aluminum 
cans (to mimic video recorders) near nests to 
familiarize birds with the recording equipment 1 
to 2 days prior to filming. We positioned hand¬ 
held camcorders (Sony Handycam DCR-SR42®) 
at nests on each recording day on tripods 0.5 
to 1.0 m from nests (Dearborn et al. 1998). 
Camcorders were programmed to begin recording 
20 min after the technician had departed (0545 to 
0730 hrs CST) to allow birds to return to normal 
behavior. Each individual recording session lasted 
4 hrs. 
Measuring Provisioning .—Video tootage was 
processed using Adobe Premiere Pro software©. 
We tabulated nestling provisioning rates (adult 
visits to nest/hr/nestling) and prey taxa for each 
1 -hr period of video footage. We identified nestling 
diet composition for taxonomical groupings of 
arthropods to Order. We measured length of each 
arthropod from the frons to the end of the abdomen, 
not including wings, antennae, or ovipositors 
(Sejberg et al. 2000). to estimate biomass (energy) 
delivered per nestling/hr. We assigned each prey 
item to one of three size categories (Schadd and 
Ritchison 1998): small adult bird beak length, 
—16.1 mm. Temple 2002). medium (> adult beak 
length and up to 2 X*s beak length), and large (>2 
X’s beak length). 
