Saddleback Journal of Biology - Saddleback College

Fall 2009 Biology 3B Paper
Red-Winged Blackbirds. Although the dyed seeds will
be beyond class aves usual nutritional diet, colored
seeds may stand out and catch their eye and therefore
display a preference toward dyed seeds.
Safflower (Carthamus tinctorius) seeds have
reasonable size, approximately 8.5 mm in length and 4
mm in width. The seed attraction chart indicates that
the primary avians that feed on Safflower seeds are
Chickadees, Cardinals, Mourning Doves, White-
Throated Sparrows, and the White-Breasted Nuthatch.
Most of which occupy the Laguna Niguel, CA. during
the months of October and November. The main
objective of this experiment is to observe colored seeds
preferences for local birds. It is expected that the dyed
seeds will be preferred among bird species in this area
because their ability to be easily identified and foraged
for.
Materials and Methods
Studies were done on the local birds at Sean
Kouyoumdjian’s house, which is located in Laguna
Niguel (Laguna Niguel, CA, USA; latitude 33° 32'
51.1512“N, longitude -117° 40' 39.7632" W).
Safflower (Carthamus tinctorius) bird feed was
purchased at PETCO in Aliso Viejo, CA. At Sean
Kouyoumdjian’s house, seeds were dyed into four
colors, red, yellow, blue, and green with Kroger brand
food dye. The feeding tray was kept in large planter in
Sean Kouyoumdjian’s backyard, where birds could
easily access it and not feel exposed to predatory
attack. All safflower seeds were exposed to the same
environmental conditions for the same period of time.
A total of 550 seeds were set out for each individual
color and feeding was allowed for an observational
time period at 10:00 AM. The seeds were set out at the
same time for additional days until one color began to
run low.
Protocols
The feeding tray was made from recycled scraps,
steel rods and poster board rectangular wooden frame
with a center divider down the longitudinal direction,
two more dividers were made forming 6 total sections.
Then poster board was stapled to the bottom in order to
hold up the seed. On the two shorter sides zip ties were
used to prevent birds from feeding on those particular
parts of the perimeter; this would eliminate
accessibility as a factor. The tray was held up by steel
rods which were connected at each corner. The use of
steel rods allowed for a variance in terrain that the tray
could be placed on. Seeds were died using Kroger ®
brand food coloring and water. They were then placed
on trays of newspaper and set to dry out. Location was
chosen based on trial and error, which led us to placing
the tray within the large planter in the back-yard. This
was advantageous to us in the aspect that feeding tray
was located within the birds’ niche and allowed a
certain comfort level for them.
Procedure
Data was collected by counting out 550 seeds,
setting them out to be eaten, and then counting the
number of seeds left uneaten. A black sheet was placed
underneath the tray to catch any seeds that were
knocked off during feeding. Seeds were covered up at
the end of every session of observation and then
continued the following day. Each time seeds were set
out the species of birds were videotaped so that they
could easily be identified later. Our data was recorded
over 3 days within a period of 2 weeks. Feeding was
allowed from 10:00 AM to about 12:30 PM for each
day. After finding the number of eaten seeds,
researchers performed a statistical using contingency
table analysis for ordinal categories.
Results
Researchers realized that birds prefer different
colored seeds depending on the niche in which they
live in. For Safflower seeds the traditional color is a
light, almost white color. Birds that eat these seeds may
prefer the natural color because it is how they have
identified their food before. However, colored seed will
stand out more in their environment and allow them to
identify food much easier. This could possibly give the
dyed seeds the upper hand. After placing the seeds out
and observing them feed, the remaining seeds were
brought in and counted. This determined how many
seeds were eaten (Figure 1). Contingency table analysis
for ordinal categories showed a significant difference
between both the number of safflower seeds eaten and
number of seeds that remained due to p-value <
0.00001. When comparing the two most eaten seeds,
tan (non-dyed) seeds and yellow seeds, a p-value
indicates a significant difference between the two.
Therefore, we can conclude, the original seeds were
preferred the most among the species of birds in this
particular niche. From the chosen color spectrum the
natural colored seed clearly was preferred among dyed
seeds having 475 out of 550 seeds eaten. The next
color that was preferred was yellow. This is probably
because it is the closest color to the non-dyed safflower
seed. Red was the least preferred having only 87 out of
550 seeds eaten. Safflower seeds were eaten by House
Finches (Carpodacus mexicanus), White-Crowned
Sparrows (Zonotrichia atripcapilla), and Mourning
Dove (Zenaida macroura).
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Saddleback Journal of Biology
Spring 2010