Hummingbirds

frostburg.edu

Hummingbirds

Difference in Color

Preference Between

Female and Male Ruby-

throated Hummingbirds

Hummingbird Group:

Justice Green, Te-Vaughn Hicks, Michelle Barillas, Raquel Martinez, and Alex Pagel

TC’s: Damani Davis and Dana Olson

Instructor: Carolina Safar


Pollination


Self-Pollination


Cross-Pollination


Why should we be concerned

about pollinators?


Pollinators are important for food

production

• 75% of flowering plants depend

on pollinators

• More than 30% of food crops

depend on pollinators

• Cross pollination produces

crops that:

– are larger

– are more symmetrical

– bring higher market values


Pollinator Declines

• Most pollinator populations are declining

– Bees

– Bats

– Birds

• Honeybee population is severely declining


Ruby-throated Hummingbirds

Could Replace Bees

•populations

increasing

•widely distributed

•pollinate many

different flowers


Attracting Hummingbirds

• Flowers

• Feeders

• Woodlands

• Open spaces

• Forest edges

• Water sources

• Red objects


• Previous study in our

area found yellow

preference

• No studies

evaluating male vs.

female RTHB color

preferences

Red vs. Yellow


Male vs. Female Hummingbirds

• Males

– Smaller

– Faster metabolism

– Shorter bills

– Ruby throats

– Forked tails

• Females

– 15-25% larger

– Longer bills

– White throats

Male

– Fan-shaped white-tipped tails

Juvenile Male

Female


Male and Female Behaviors

• Male priorities:

• Courtship displays

• Defending territory

• Male “energy crisis”

• Female priorities:

• Caring for young

• Feeding herself and her young


Why Females and Males May

Differ in Color Preference

• Females prioritize

feeding

– May be attracted to

yellow for high nectar

• Males do not prioritize

feeding

– May not have color

preference


Our Hypothesis

Hypothesis: Female ruby-throated

hummingbirds will feed from the yellow

feeder openings more frequently than will

males.

Null Hypothesis: There will be no difference in

preference for yellow between female and

male ruby-throated hummingbirds.


Materials and Methods


• Study Site

– Isolated residence

• Garrett county

• open lawn

• forest edges

• flowering plants

• June 21st, 2009

Study Site


• 2 Feeders

Feeders and Set-up

– Aqua Pod water bottle

– ½ pint deli dish

– Foam disks

– Wire to suspend

• Sugar solution

– 4 cups of water: 1 cup sugar


• Feeders suspended

– from gardening poles

– 5-6 ft. from ground

– 7 inches apart

– 2 feet from a window

Set-up


Video Equipment Set-up

• SONY HD 2500 digital

video camera on a

tripod

• Zoomed onto both

feeders

• Recorded from 7a.m. to

1 p.m.


Data Collection

• Video was divided into 1 hr sections

• Data recorded for each RTHB:

– Sex (m, f) or “unknown”

– Color of feeder opening

– Number of feedings

• % of males and females feeding at each color

were calculated from the total male and female

feedings


Data Analysis

• Used two-tailed z-test with 95% confidence

level to evaluate significant differences:

– Between male and female feedings at yellow

– Between male and female feedings at any other

color


Results


Total male feedings = 227

Total female feedings = 868

Results

Total “unknown” feedings = 367

Male Female Unk.

Red 18% 16% 17%

Yellow 42% 43% 43%

Green 24% 15% 29%

Blue 16% 26% 11%


• The results of our z-test for

feeding frequencies at

yellow were:

– Z-value: 0.196

– Confidence Level: 15.5%

• Failed to reject our null

hypothesis

• There was no significant

difference between males

and females in their

preference for yellow

Results


Percent of Feedings

50

45

40

35

30

25

20

15

10

5

0

Color Preference of Ruby-throated

Hummingbirds

Red Yellow Green Blue

Male

Female


Discussion and Conclusions


What Do These Results Mean?

• Males and females prefer yellow equally

– Both seeking a higher nectar load?

– Both recognize yellow color easily?

• Females preferred blue more than males;

males preferred green more than females

– No clear reason

– Could be investigated further


Application

• Advise farmers to post yellow flagging near

crops

– Attract RTHBs to area

• Post blue flagging during summer

– Females’ second preference was blue

• Also post green flagging during fall

– Males’ second preference was green


Limitations to This Study

• Difficulty determining sex of RTHBs

– Feeder position blocked view

– Blur in video

– Season of study => juveniles

• Conducted study in only one location

• Length of recording

– Analyzed 6 hours of one day

• Lack of equipment

• Consistency in data collection


Suggestions for Future Studies

• Different season

– Particularly fall

• Different locations

– RTHBs have a wide

distribution

• More cameras; camera from above feeder

• Test other color feeder openings

• Test if flagging attracts RTHBs to farms


• Competition?

• Color/position memory?

• Effect of nectar load?

• Territory boundaries?

• Effect of habitat factors?

– Water source

– Open spaces

– Forest edge

Other Questions


What We Have Learned

• RTHBs are important

creatures

• RTHB behaviors

should be studied

further

• Pollinator decline

must be stopped


“The happiness of the bee and the

dolphin is to exist. For man, it is to

know that and to wonder at it”

Jacques Yves Cousteau


Questions?

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