The Preference of Different Colored Seeds by Birds in Laguna Niguel, California




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The Preference of Different Colored Seeds by Birds in Laguna Niguel, California
Hamidreza Hoveida and Sean Kouyoumdjian

Department of Biological Science

Saddleback College

Mission Viejo, CA 92692
According to some articles found colored seeds may attract class Aves better than the typical unsaturated color. This might suggest that birds may show preference to colored seeds during feeding. A set of red, blue, green, yellow, and tan (non-dyed) colored safflower (Carthamus tinctorius) seeds were exposed to the bird environment in the city of Laguna Niguel, CA. All seeds were exposed to same conditions at for the same period of time. Each color was placed in its own individual section so that randomness would not play a role and colors were easily identified among birds. The number of seeds initially set out were counted and then set out for the test. After few seeds remained of one color, all seeds were brought in and counted. The number of seeds eaten could then be calculated. This showed that out of 550 seeds 475 tan (non-dyed), 87 red, 125 blue, 265 yellow, and 167 green seeds had been eaten. When comparing the two most eaten seeds, tan (non-dyed) seeds and yellow seeds, a p-value < 0.00001 indicates a difference between the two. Results indicate a larger preference toward the natural colored seed, Tan (non-dyed). Observations of birds feeding on Safflower seeds were also noted. We found that the most common birds to feed were House Finches (Carpodacus mexicanus) and White-Crowned Sparrows (Zonotrichia atripcapilla). Also a Mourning Dove (Zenaida macroura) was spotted sitting within the feed tray and may have possibly consumed seeds.


Introduction

Organisms from class aves are known for their ability to see extremely well and depict their surroundings in color. Without it they would be unable to identify members of their species and reproduce. Because of their incredible vision, color plays a vital role in survival and food foraging. Selection of food source can depend significantly on morphology of bird beaks and as seen in the study by Snow (1954) it can sometimes determine habitat of particular species. Avian preferences can be very determinate of what they look for in a food source. Information about color avoidance by avian species can benefit business owners and farmers like in the study done by Avery, et al. (1999). They were able to determine that white seeds were consistently eaten the most and blue the least among Red-Winged Blackbirds. Although colored seeds will be beyond class aves’ usual nutritional diet colored seeds may stand out and catch their eye and therefore show a preference to the dyed seeds.

Safflower (Carthamus tinctorius) seeds are a 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 Laguna Niguel, California during the months of October and November. The main objective of this experiment is to observe colored seed preference in local birds. It is expected that the blue seeds will be preferred among bird species in this area because of the trend we have seen within research.

Materials and Methods

Seed

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. It was then transferred to Sean Kouyoumdjian’s house where they were dyed into four colors, red, yellow, blue, and green. The feeding tray was kept at a prime location where birds could easily access it and not feel exposed to predatory attack. All safflower seeds were exposed to the same environmental conditions. 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 until one color began to run low.


Protocols and creation of bird feed trays

The feeding tray was created from old, scrap wood, steel rods and poster board. After nailing together a rectangular wooden frame with a center divider down the longitudinal direction, two more dividers were created 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. Location was chosen based on trial and error, which led us to placing the tray within the large planter in Sean Kouyoumdjian’s back yard. This was advantageous to us in the aspect that it was located within the birds’ niche and allowed a certain comfort level for them.


Measurements

Measurements were taken 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 can easily be identified later. Our data was recorded over a period of 2 weeks. After finding the number of eaten seeds, we then did stats analysis using contingency table analysis for ordinal categories.


Results

Some birds prefer different colored seeds depending on the niche in which they live in. For Safflower seeds the traditional color is a light, tan almost white color. The customary birds that eat this seed 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 colored seeds the upper hand. After placing the seed out and observing them feed the remaining seeds were brought in and counted. This determined how many seeds were eaten (Table 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 < 0.00001 indicates a difference between the two. Therefore we can conclude that the original, tan (non-dyed) seeds were preferred the most among the species of birds in this particular niche (Figure 1).

From the chosen color spectrum the natural colored seed clearly was preferred among the dyed seeds. 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 (Figure 1). Safflower seeds were eaten by House Finches (Carpodacus mexicanus), Mourning Dove (Zenaida macroura), and White-Crowned Sparrows (Zonotrichia atripcapilla).

Number of Seeds

Tan (non-dyed)

Red

Blue

Yellow

Green

Initial

550

550

550

550

550

Final

75

463

425

285

383

Eaten

475

87

125

265

167


Table 1. Table displaying the number of seeds set out, number of seeds left, and the number of seeds eaten. Shows this data for tan (non-dyed), red, blue yellow, and green.

Figure 1. Bar graph displaying the number of seeds eaten for individual colors. 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.
Discussion

The results show that there was a significant difference between the tan (non-dyed) seeds and the dyed colors of red, blue, yellow, and green. The tan (non-dyed) was preferred above the other colors with significant difference disproving our expectations of blue seed being favored. Others have found similar information pointing to the natural colored seed as the most preferred. Avery and colleagues (1999) found that among Captive Red-Winged Blackbirds and Boat-Tailed Grackles, lighter colored seeds and those that were closer to natural color were preferred. This was primarily due to the fact that colored seeds are not a domestic color to captive Red-Winged Blackbirds and Boat-Tailed Grackles. The vision of many avian species comes very close to ultraviolet wavelengths (Parrish et al. 1984). This may be an explanation to why the reflectance of ultraviolet light from blue seeds detour these birds from that color choice.

Although previous research may indicate that colored feed was more preferable, such as in Frank and Mary Slaby’s experiment. In their experiment red peanuts had were more preferred by Steller’s Jays over other colors (1977). Cromie, etal., (1993) did a similar test to Slaby in which they tested the influence of fruit color on feeding of preferences of American Robins. They found surprising results showing that blue colored fruit was favored over their traditionally eaten red fruit. Pank (1976) also realized that colored seeds were preferred over non-colored seeds. Also during his experiment he resulted in there being no significant difference between accepted seeds due to colored backgrounds. When looking at Goforth and Baskett’s (1971) experiment they indicated that the effects of colored backgrounds on food selection were able to be determined. Results showed penned Mourning Doves preferred blue backgrounds more than red, green, and yellow, which opposes Pank’s inconclusive results among colored background.

Preference to the domestic color that these particular birds feed on probably had the highest influence on seed choice. To expand upon this another route of exploration would be to repeat this experiment over a longer period of time. This would allow local birds to become adapted to the new food source and possibly change their typical feeding habits.


Acknowledgements

We would like to thank Professor S. Teh for his helpful comments and encouragement, without which this project would have never seen completion. We would also like to thank Mr. and Mrs. Kouyoumdjian for their help in funding the experiment and for setting up the location. Because of their help, everything was able to be carried out smoothly.



References

Avery, Michael L.; Decker, David G.; Humphrey, John S.; McGrane, Arlene P. 1999. Seed Color Avoidance by Captive Red-Winged Blackbirds and Boat-Tailed Grackles. The Journal of Wildlife Management, Vol 63, No. 3,1003-

Cromie, E. A.; Meyers, E.; Minor, M.; Murray, K. G.; Winnett-Murray, K. 1993. The Influence of Seed Packaging and Fruit Color on Feeding Preferences of American Robins. Vegetatio, Vol. 107/108, 217-226

Baskett, Thomas S.; Goforth, W. Reid. 1971. Effects of Colored Backgrounds on Food Selection by Penned Mourning Doves (Zenaidura macroura). The Auk, Vol 88, No. 2, 256-263

Pank, Larry F. 1976. Effects of Seed and Background Colors on Seed Acceptance by Birds.The Journal of Wildlife Management, Vol. 40, No. 4, 769-774

Parrish, J. W., J. A. Ptacek, and K. L. Will. 1984. The detection of near-ultraviolet light by nonmigratory and migratory birds. Auk, 101:53-58

Slaby Frank; Slaby, Mary. 1977. Color Preference and Short-Term Learning by Stellar’s Jays. The Condor, Vol. 79, No. 3, 384-386

Snow, D.W. 1954. The habitats of Eurasian tits (Parusspp.). Ibis, 96: 565-585.





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