400 
THE WILSON JOURNAL OF ORNITHOLOGY • Vo/. 124. No. 2, June 2012 
information is available regarding the interactions 
between grassland birds and rowerops (such as 
corn and soybeans) that have the potential to be 
mutually beneficial (e.g., Bollinger and Caslick 
1985a). 
Eastern Meadowlarks (Stumella magna) inhab¬ 
it a wide variety of grassland habitats throughout 
the Midwest (Bollinger 1995, Lanyon 1995. 
Kershner 2001, Ribic and Sample 2001, Walk 
et al. 2010). preferring to forage on the ground 
and primarily feeding on arthropods (Beal 1948. 
Lanyon 1995). Nestling diets of Eastern Mead¬ 
owlarks have not been closely studied. However, 
movements of adults have been monitored using 
radiotelemetry, indicating they routinely forage in 
rowerops. especially soybeans (Kershner 2001, 
Kershner et al. 2004). These findings suggest 
further study of the importance of grassland 
patches within a rowerop agricultural land matrix 
is warranted. We examined (he nestling diet of 
nesting Eastern Meadowlarks in grasslands adja¬ 
cent to corn and soybean fields. 
METHODS 
Study Area. —We conducted research in eight 
Conservation Reserve Program (CRP) fields 
ranging in size from 1.35 to 20.80 ha. These 
fields were planted primarily with redtop (Agros- 
tis alba) and orchard grass ( Dactyl is glome rata). 
All CRP tracts were bordered on most sides by 
corn and soybean fields with some small forest 
fragments and wooded hedgerows. 
Nest location.— We located nests using die 
rope dragging technique (Higgins ct al. 1969). 
Each nest was marked 5 m to the north with 
flagging tape. We recorded nest status and 
monitored each nest every third day until fledgina 
or nest failure, noting the date, the number of eggs 
or nestlings, female presence, and condition of 
eggs (warm or cold). 
Nestling Diet.—We assessed types of foods fed 
to nestlings using esophageal ligatures. This 
technique was performed at each nest twice (3- 
and 6-day old nestlings) during the 10-day nestling 
period. One person removed all of the nestlings 
after a parent had been observed leaving a nest and 
brought them to an area at least 100 m from the nest 
to apply ligatures. Ligature materials consisted of 
10.2-cm cable ties (Mellot and Woods 1993). 
These were fastened around the necks and adjusted 
so individuals could breathe but not swallow food 
items. Nestlings were returned to the nest after 
igature application (~J min/bird), and left for a 
period of 20-60 min or until two foraging trips of 
adults had been observed. Nestlings were once 
again removed from the nest, and food was 
transferred from their esophagus and placed into 
a vial of 80% ethanol. Food items from each nest 
were placed into separate vials. Volumes wete 
measured by liquid displacement (Bollinger and 
Caslick 1985b). Mealworms were given to each 
nestling to replace the lost meal and nestlings were 
subsequently returned to the nest. We combined 
data from the different age classes to increase 
sample sizes. 
RESULTS 
We collected 29 ligature samples from 19 
different Eastern Meadowlark nests between April 
and August 2002. Spiders (Araneae). including 
egg sacs, represented the largest volume of food 
items (44%) as well as the largest number of 
individual food items (53%). The most common 
lamily of spiders was Lycosidae (wolf spiders, 
primarily Hogna spp., 80% of spider specimens). 
Other lamilies included jumping spiders (Salt- 
icidae), 10%; crab spiders (Thomisidae), 4%; orb 
weavers (Araneidae), 4%; and sac spiders (Gna- 
phosidae), 2%. Orthopterans comprised the sec¬ 
ond largest volume of food items (23%, 13.5%of 
food items) including crickets (Gryllidae). 46% of 
orthopterans: grasshoppers (Acrididae). 31%; 
and katydids (Tettigonidae), 23%. Lepidoptera 
larvae followed closely with 18% of the specimen 
volume (14.6% of items), consisting mostly of 
cutworms (Noctuidae), 73% of lepidopterans: 
and sullur butterfly caterpillars, (Pieridae), 27%. 
Adult lepidopterans were not found in our ligature 
samples. Other taxa were Coleoptera (mostly 
Carabidae and Scarabidae), 10.8% (15.6% of 
items), Homoptera (Cicadidae), 2.0% (1% of 
items), and Hemiptera (Pentotomidae). 1.9% 
(2.1% of items). 
DISCUSSION 
Composition of Nestling Diet.— Previous stud¬ 
ies examining the diet composition of adult 
Eastern and Western ( Stumella neglecta) mead¬ 
owlarks revealed several dietary preferences. 
Orthopterans composed the largest proportion of 
animal matter, whereas beetles and caterpillars 
also were commonly found in the stomachs of 
these birds ( Beal 1948. Bent 1958). Spiders were 
occasionally identified, but they were not ob¬ 
served in large numbers and contributed little to 
overall prey percentages (Beal 1948). However. 
