Patricia+Kephart

Hummingbird Inquiry Robertson Intermediate Daly City, CA

INTRODUCTION While trying out many options for studying bird baths I observed Anna's Hummingbirds in the trees around my home. They seem to wake up in the dense pine tree in the early morning. I watched them feeding on sunny days and chase each other from specific plants. I even heard agitated clicking noises, and turned to see a Red-shouldered Hawk taking off! It got me wondering why I saw them around the flowering plants on sunny afternoons, but not much on foggy cool mornings. From my reading I learned that hummingbirds sleep in a state of torpor where their metabolic rate is slowed to 1/15th of its normal rate, and that it sometimes takes up to an hour for the sun to warm them up.

Maybe this applied to the normal weather pattern here on the coast in summer. Early mornings typically are foggy and cool. By noon the fog burns off. The day warms up. Could it be that my hummingbirds weren't active until the sun burned off the fog? I also wondered if nectar production of flowers would be a variable, and learned that while studies show that individual flowers produce more nectar after rain, nectar production is highly variable. I also learned that flowers produce nectar for about a week. This was good because my study would be for 7 to 10 days and the tree I planned to watch was in full bloom, it is an Australian fuchia tree.

QUESTION: Will hummingbirds be more active when it's sunny and warm than when it's foggy and cool?

HYPOTHESIS: If the temperature is 15° C or more, then there will be a greater number of hummingbird feeding visits.

MATERIALS AND METHODS:

I will observe a flowering shrub in my yard at two different times of the day: 6:30 - 7:00 a.m. and 3:00 - 3:30 p.m. for 9 days. I will record the temperature and the number of hummingbird visits during each half hour observation.

MATERIALS:
 * observation log/tally sheet with dates/times/temperature
 * thermometer
 * binoculars
 * clock

My independent variable is temperature.

My dependent variable is the number of hummingbird visits.

My control variable is to observe from a stationary location. I will use a view of my back yard where I can see a newly hung hummingbird feeder and a fuchia tree. It is an area sheltered from the wind.



DATA:



COMPARISON of MORNING DATA > 15 *C and AFTERNOON DATA __<__ 15*C

My data suggests that temperature does affect the number of hummingbird feeding visits. The two coolest days had the lowest number of visits.

I noticed that the average temperature during this period was close to 15*C, but that morning temperatures were much cooler than afternoon temperatures. I was surprised to see that there were more frequent feeding visits during the cool mornings. The scatter plots of morning versus afternoon activity show more visits at cooler temperatures. This suggests that time of day affects the number of feeding visits more than temperature.

The data supports my hypothesis that if the temperature is 15*C or greater there will be more hummingbird feeding visits.

SCIENTIFIC CONCLUSIONS: Warm temperature increases hummingbird activity. However, I need to do more observations on days when the average temperature is well below 15 *C to see what the breaking point temperature is. I looked at morning vs. afternoon data to note that hummingbirds were often more active in the cooler part of the day. This surprised me. But, the coldest day, when the average temperature was only 12.5 *C, had the fewest visits. I observed the hummingbird sitting on a branch with fluffed feathers for 13 minutes before flying to the feeder. Hummingbirds perched for brief time periods every other observation day.

ALTERNATIVE EXPLANATIONS: By the end of the week there was much more hummingbird activity. They increased visits to the feeder as the week went on. This could mean that it took the week for the birds to find the feeder.

The coldest day was foggy and windy all day. The wind could have been a factor. The fuchia tree was protected by the house, as was the feeder, but that day was windy even behind the house, and only the feeder was protected.

PROBLEMS: My findings were influenced by the time of day I did my observations. I could add an evening observation to see if there is a pattern of number of visits at another time of day.

NEW QUESTIONS: My original question had to do with sunny versus foggy weather. During a longer study over other seasons I will be able to observe cold, sunny conditions to see if temperature rather than sunshine is the determining variable. If I wanted to test the question of whether or not foggy conditions affect hummingbird feeding visits, I would need to measure relative humidity. Temperature rose after the fog lifted. My morning observation data show that the hummingbirds were more active in the morning. I wonder if fog matters at all? The other question is the influence that wind has on hummingbirds. I wonder if windy conditions would significantly affect the number of visits?

REFERENCES: Baughman, Michael. "The Hummingbird Facts and Information." Online: //How to Enjoy Hummingbirds.// 2010//.// 2 July 2012//..

Keasar, Tamar. "Variability in Nectar Production and Yield, and their Relation to Pollinator Visits, in a Mediterranean Shrub." Online: //Ideas at the Research Division of the Federal Reserve Bank of St. Louis.// July 2007//.// 2 July 2012//..

Nepi,Massimo and Ettore Pacini, //Nectaries and Nectar.// Dordrecht, The Netherlands: Springer, 2007.