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THE WILSON JOURNAL OF ORNITHOLOGY • Vol. 123, No. 3, September 2011 
2003 at the Blue Grass Army Depot (BGAD), 
11 kin southeast of Richmond, Madison County, 
Kentucky. The BGAD is a matrix of woodlots, 
open fields, and pastures. 
Field Methods. —We captured Grasshopper 
Sparrows in mist nets beginning in early May, 
either using playback of conspecific songs to lure 
males into nets or flushing females into nets 
placed near nests. All captured sparrows were 
banded with a numbered USGS aluminum band 
plus a unique combination of three colored leg 
bands. 
Nestling age (days) 
□Males 
■ females 
Nests were located by watching the behavior of 
adults, particularly adults carrying nesting mate¬ 
rial or food in their bills. Nests found during 
incubation were checked at least every 3 days 
until eggs hatched. A dummy camcorder was 
placed near the nest (1-1.5 m away) for at least 
24 hrs just prior to or shortly after eggs hatched to 
acclimate adults to its presence. 
Nests were videotaped using camcorders 
mounted on tripods. All taping was conducting 
during the morning and early afternoon (0700- 
1200 hrs). The mean ± SE duration of taping 
sessions (» = 108) was 3.1 ± 0.1 hrs. Four pairt 
of Grasshopper Sparrows re-nested and we 
v^eotaped both their first and second nests. 
Wc viewed all videos and. for each adult visit 
to a nest, we noted its gender (based on leg bands) 
and recorded the size, identity, and number of 
prey items delivered. Prey size was estimated by 
comparing the length of prey to the length of the 
adult s beak. We estimated the length of prey 
delivered and multiplied prey length relative to 
the length of the bill by 11.4 mm (intermediate 
between the mean bill lengths of male 111.9 mml 
and female (10.9 mml Grasshopper Sparrows) 
(Crossman 1989). Prey items were identified to 
taxonomic order, except larval insects were 
classified as larvae. We estimated the amount of 
prey biomass delivered to nestlings using the 
formula: prey biomass = number of adult visits/hr 
x mean prey size x mean number of prey. 
Statistical Analysis .—Repeated measures anal- 
ys.s of variance (ANOVAJ was used to examine 
the effects of nestling age, brood size, and brood 
number on provisioning behavior (rates and prey 
biomass) of male and female Grasshopper Spar- 
ws. We used Student-Newman-Keuls (SNK) 
multiple comparison tests to ascertain which 
mea ns differed. Repeated measures ANOVA 
beiwro° ‘° examine P° ss ‘kle differences 
between males and females in provisioning 
- .. —-vv... vi iiwauiii^ uii mean i- 
provisioning rates of male and female Grasshopper 
Sparrows. 
behavior. Videotaping effort varied among nest¬ 
ling ages (i.e., sample sizes for some days were 
relatively small) and nestlings in some age groups 
were grouped into age categories (e.g., 1-2 days 
post-hatching) for some analyses. All analyses 
were performed using SAS statistical software 
(SAS Institute 1999). Values are presented as 
means ± SE. 
RESULTS 
We videotaped nests of 15 pairs of Grasshopper 
Sparrows during 2002 and 2003, including one 
nest each for 11 pairs and two nests for four pain. 
Both nests were taped for the latter four pairs 
during the same breeding season (representing 
first and second broods). The mean number of 
nestlings per nest was 4.0 ± 0.2 (range = 3-5) 
with means of 4.2 ± 0.2 for first nests (n = 15) 
and 3.3 ± 0.3 lor second nests (n — 4). 
Female Grasshopper Sparrows made 629 visits 
to nests (41.5% of 1,516 total visits), whereas 
males made 531 visits (35.0% of visits). Vegeta 
lion obscured our view of some visiting adults and 
we were unable to identify visiting adults during 
356 visits (23.5% of visits). There was no 
difference in provisioning rates between males 
and females (f, J3 = 2.6. P = 0.13) with mean 
provisioning rates of 2.16 ± 0.16 visits/hr for 
females (n = 93 observation periods) and 1.86 - 
0-14 visits/hr for males (n ~ 93 observation 
periods). There were no significant interaction 1 , 
between gender and brood number (first vs. second 
nest; P — 0.79), and gender and brood size (.P ' 
0.22). The interaction between gender and nestling 
age approached significance (P = 0.053), but 
comparison of male and female provisioning rate'* 
did not reveal a clear trend (Fig. 1). 
