Posted by Bird House Guy | Posted in Hummingbird feeders, Hummingbirds, wildlife | Posted on 23-10-2009
Recently, I was asked the question concerning hummingbirds and their feeding habits. The individual was concerned about the fact that when it rains, she rarely sees the hummingbirds at the feeders. She understood that hummingbirds had to feed at least 5 times a day and asked me why they were not going to the feeders. I thought this might interest other readers on the subject of feeding hummingbirds and hummingbirds feeding. I hope these facts will put you at rest as to the behavior of the hummingbirds and their feeding habits during inclimate weather. Back in 1993, Dr. Reed Hainsworth, Ph.D and Dr. Larry Wolf, Ph.D helped to shed some light on the subject of hummingbirds feeding.
Obtaining the food needed to live from day to day is a fundamental part of life for birds. Imagine small hummingbirds discovering a large amount of food in one place, such as a feeder. For them a feeder is supernatural. Within a very short time at a feeder, a small, hungry hummingbird can solve its immediate requirements for food.
Hummingbird Feeding
The very size of hummingbirds makes their survival an even bigger adventure. Hummingbirds must eat more than their weight in food each day, and they fulfill this need by eating often. Because their survival depends critically on eating frequently more than any other animal – they continually face the danger of starving.
Hummingbird Meals
How much and how often do hummingbirds eat? When we studied hummingbirds in the laboratory, we found that they, like humans, eat meals. A meal is a relatively quick and large intake of food, which is followed by time when no feeding occurs while the energy that has been consumed is used. In the lab, hummingbird meals are easy to observe because the birds fly from feeders back to a perch, and they do not come back to a feeder until they are ready for their next meal.
An X-ray of a Magnificent Hummingbird shows what happens to a meal once it is eaten. Food initially passes to an elastic sac in the neck called a crop, which serves the same storage and supply functions as a stomach. Small amounts of food empty from the crop and pass to the Intestine, where sugar is assimilated into the blood.
We found that when using a relative rich sugar solution, a three gram male Ruby-throated Hummingbird ate five meals an hour. For each meal he consumed a little less than 1/100 of a fluid ounce.
The crop emptied more rapidly when the energy (sugar) content of its food was lower. Each meal weighed about one-quarter gram, so with 14 meals an hour, the three-gram bird ate 3.6 grams, or more than his weight in one hour! Over a 12-hour daylight feeding period, this hummingbird ate 43 grams of sugar water, or 14 times his weight in food. Even with the richer food, he ate 5.4 times his weight in a day.
The Impression from this frantic eating schedule seems to confirm that a hummingbird might very quickly starve to death if it does not eat in a short time. How, then, do these birds manage to survive overnight without eating?
To find out, we measured the amount of energy they used compared to the energy they ate. We measured energy they used while they perched and while they hovered, and we found a three-gram hummingbird used 15 times more energy in a minute to hover than to perch. When we added up the energy a hummingbird used after it ate a meal, we found it went back to eat again before it had utilized all the energy it had eaten. Some energy from each meal was saved and stored as fat.
Energy storage keeps a hummingbird from starving, but not for long. The energy stored by the end of a day usually is just sufficient to survive overnight.
What happens if a hummingbird cannot feed enough, or if it is cold and more energy must be used to keep warm overnight? Fortunately, hummingbirds, like hibernating mammals, can lower their body temperature overnight to conserve energy.
However, we found that hummingbirds do not lower their body temperature unless there is a danger they actually may starve. Even with their abilities to save some energy and to conserve energy in an extreme crisis, the impression is that small hummingbirds face big problems because they must eat often.
One way to help solve the problem is to eat energy-rich food; a hummingbird can store more energy from each meal, so their survival problems are reduced by feeding on rich foods. Hummingbirds spend most of their feeding time visiting flowers to eat nectar.
***For more information on how to aide your local hummingbirds in feeding them, simply visit: www.wildlife-houses.com or if you have questions concerning feeding hummingbirds, feel free to contact me at freedomenterprises@bresnan.net.
The Birdhouse Guy!
