Color Preferences of Two Species of Dominican Hummingbirds and Bananaquits

Hannah Rice

Texas A&M University Tropical and Field Biology Dominica Study Abroad 2015 Dr. Thomas Lacher Dr. James Woolley

Abstract

There are three species of hummingbirds that occur at the Archbold

Research Center as well as the nectar feeding Bananaquit. This study expanded on hummingbird research done in the past. Five hummingbird feeders were set up at the lowest garden on the station. A water to sugar ratio of 4:1 was used in the feeders. The feeders were altered so that 5 colors were presented: red, blue, green, grey and gold. I observed and recorded color preferences of the foraging hummingbirds. It was observed that the hummingbirds showed a high preference for the red feeder, while the Bananaquits favored colors other than red.

Introduction

Hummingbirds see near the range of ultra-violet light, but they can still see color in the visible spectrum. However, brighter colors are more obvious, typically making reds and pinks more noticeable to them, even though they will drink nectar from anything (Goldsmith, 1980). It has been found that brighter blooms in the UV often have a higher sucrose concentration than the blooms in the cooler toned spectrum, thus attracting hummingbirds to the brighter plants due to their past experience (Friedman & Friedman, 2015). There are four species of hummingbirds on Dominica: Eulampis jugularis

(Purple-throated Carib), Sericotes holosericeus (Green-throated Carib), Orthorhyncus cristatus (Antillean Crested Hummingbird) and Cyanophaia bicolor (Blue-headed

Hummingbird). The Blue-headed hummingbird is not present at the field station and the Antillean Crested was not seen often; therefore, the latter species were rarely observed in the experiment. Also included in the experiment was the

Bananaquit (Coereba flaveola) as it is a nectar feeding bird in great abundance. Past student research has studied hummingbird behavior in regards to placement of the feeders (Smith, 2013) and sugar concentration (Barrera, 2002). These reports showed that hummingbirds are more likely to feed from the feeder when it is at a higher level and when the water sugar ratio is a 4:1. I hoped to add to the accumulated data observations on the ideal feeder color, to see if it has an affect on the number of hummingbirds and which species visit each color.

Methods and Materials

Five identical red feeders were used as to limit variability. Four of the five feeders were spray painted a different color (green, blue, grey, gold). The last feeder was left red. A water to sugar ratio of 4:1 was mixed and poured into each feeder.

The feeders were then hung on a long piece of rope between two trees in the lower garden of Archbold Tropical Research and Education Center, Springfield, Dominica.

They were spaced about 2.5 feet apart from each other. As the hummingbirds came to feed, the species and color of the feeder were recorded. Five of one hundred- twenty permutations of color order were recorded over five total days. The feeders were watched from early morning until late afternoon. Observations were taken from the first terrace while using binoculars.

Results

Table 1: Color by Species Crosstabulation

Color Green-throated Carib Purple-throated Carib Bananaquit TOTAL at color Red 33 40 36 111 Gold 3 3 37 37 Grey 1 2 21 24 Green 4 0 1 5 Blue 0 2 10 14 TOTAL species count 41 47 99 191 Table 1: Color by Species Crosstabulation: The table above shows the number of birds that fed at each colored feeder arranged by species and color.

Figure 1: Percentages of feeding

Green Throated Carib Purple Throated Carib Green Grey 10% Grey Blue 2% 4% Gold Gold 4% 7% 7% N=47 N=41

Red Red 81% Blue 85% Green 0% 0%

Bananaquit All Nectar Feeding Species Blue Blue 10% Green 6% Green N=99 3% 1% Grey N=187 13% Grey Red 21% 37% Red Gold Gold 58% 31% 20%

Figure 1: Percentages of feeding: The charts above show the percentage of each species that chose the colored feeders. Table 2: Merged Data

Species Color Number Green Throated Red 33 Green Throated Other 8 Purple Throated Red 40 Purple Throated Other 7 Bananaquit Red 36 Bananaquit Other 63

Table 2: Merged Data: The above table showed the merged data that was used in the Chi-Squared Test

Table 3: Chi-Squared Test

Pearson df p value Chi- square* 41.8 2 <0.001 *for statistical purposes, p=red and q=other

Table 3: Chi-Squared Test: The above table shows the Chi-squared value and level of significance.

Discussion

It was found that color preference was not independent of species, as seen in

Table 3. The Purple-Throated Carib and Green-Throated Carib both showed significant preference for the red hummingbird feeder. The Bananaquit, however, showed significant preference for colors other than red, with the exception of green.

These preferences can be seen in Figure 1.

Though hummingbirds see in ultra-violet, red is closest to infared rays.

Something other than UV sight causes their attraction towards the red feeder. Red was the brightest color, which could have caused them to be more drawn to that feeder. Only Green-Throated Caribs chose the green feeder to any degree. The

Bananaquits also have UV sight, though they have a more varied diet. This varied diet could cause them to seek out other nectar sources than the typical red. The results could be biased due to the fact that red is the typical feeder color, and the hummingbirds could be conditioned to seek out the red feeders for the nectar as that is what they are used to. However, no feeders were present anywhere on the station; none were ever hung according to the station director. I was also unable to complete all 120 permutations; further testing of all permutations could influence the results somewhat.

Works Cited Barrera, D. (2002). Patterns in the foraging time of Eastern Caribbean Hummingbirds as a function of sucrose concentration. Retrieved from http://dominica.tamu.edu/student%20projects/Dominica%20Projects%20pdf%20 copy/Barrera_Daniel.pdf

Friedman, J., & Friedman, S. (2015, January 1). Hummingbird Color Preferences. Retrieved March 29, 2015, from The Wild Bird Store: http://wildbirdsonline.com/articles_hummingbird_color_preferences_for%20cc.ht ml

Goldsmith, T. (1980). Hummingbirds see near ultraviolet light. Science . 786-788.

Smith, M. (2013). Feeding and Foraging Behaviors of Dominican Hummingbirds and the Bananaquit in Relation to Feeder Height . Retrieved from http://dominica.tamu.edu/student%20projects/Dominica%20Projects%20pdf%20 copy/Smith_Megan_2013.pdf