We have certainly come a long way in our understanding of bird migration. For example, it is hard to believe that during the early days of the founding of the United States it was popularly believed with the onset of winter, hummingbirds “migrated” only as far as a nearby tree and impaled its bill in the plant’s trunk. Here it remained immobile until the land thawed the following spring.
Nowadays, through the hard work of many ornithologists, we have a far better understanding of how birds fly from their breeding grounds to their winter homes and back with unbelievable accuracy. This research has reveal birds employ a number of environmental clues such as polarized light, the stars, the sun and even magnetic fields to steer the their course on their epic migratory journeys.
Have we answered all of the mysteries of bird migration? Many of us believe we have much more to learn. I, for one, cannot wait to see what future research will reveal.
Modern technology is having an awesome impact on wildlife research. Drones are now permitting biologists to assess such things as wildlife habitats and animal behavior in a fraction of the time and effort it would take using techniques that are more conventional. Even PIT (Passive Intergrated Transponder) technology is enabling biologists to track the movements of animals as small as a hummingbird.
If a dog or cat has found a Forever Home in your residence, you are familiar with PIT tags. Most dogs and cats carry a PIT tag. However, PIT technology has advances enough to the point where miniaturized tracking devices are tiny enough to be used to track the movements of a hummingbird. As with our pets, these extremely small devices are delicately inserted beneath the animal’s skin
With this technology, biologists can easily track the movements of individual hummingbirds going about their daily lives. A group of researchers from the University Of California Davis School Of Veterinary Medicine recently reported the results of their study designed to track hummingbirds visiting feeders in a suburban backyard. Each time a hummingbird visited a feeder their visit was logged by a scanning device similar to those used when we purchase everything from books and clothing to groceries.
The study involved placing PIT tags in Anna’s and Allen’s hummingbird and then recording how often and long each tagged bird visited the seven feeders scattered about the yard. From September 2016 through March 2018, the birds visited the feeders roughly 65,500 times.
Among the fascinating facts the biologists have gleaned from their study are:
● Female hummingbirds have a tendency to linger longer at feeders than males.
● During the spring and summer hummingbirds visit feeders more often in the morning and evening than at any other part of the day.
● Male hummingbirds more often feed with other males than with females.
Do any of these findings hold true with what you have observed watching ruby-throated hummingbirds in your backyard?
If you live in Georgia, it is next to impossible not to hear the cheery vocalizations of the Carolina wren. I hear them throughout the year. In fact, the song of a Carolina wren is often the first sound I hear when I step outside in the morning. This has made me wonder how often a wren calls in day.
Recently while conducting research on backyard wildlife I found an answer to this perplexing question. It seems that it has been documented that a captive male Carolina wren actually sang 3,000 times in a single day!
I must admit, I had no idea a Carolina wren could accomplish such an impressive fete.
We are all concerned about the health of the hummingbirds that we host at our hummingbird feeders. Consequently we try to keep our feeders as clean as possible in hopes that microbes living on our feeders and the nectar we offer are not going to cause a health problem for our hummingbird neighbors. For the first time, researchers have focused on what microscopic critters dwell in backyard feeders.
Scientists at the University of California, Davis, conducted the research. The research team carried out their study in a backyard located in Winter, California. Both Anna’s and black-chinned hummingbirds frequented the feeders in this yard.
During the study, the microbe communities living in the sugar water offered in feeders, on nearby flowers producing nectar, as well as on the hummingbirds themselves were compared.
The results of the research project indicated that the majority of the bacteria growing in the hummingbird food offered in feeders did not pose a significant health threat to hummingbirds or humans. However, also present were much smaller populations of bacteria and fungi that could potentially have a harmful effect on humans and hummers.
It should be noted the scientists found deionized water harbored the most fungi. In comparison, bacteria were most abundant in tap and bottled water.
The research team recommended that cleaning hummingbird feeders away from locations where food is prepared. This would minimize the risk of a potentially harmful pathogen would be spread to humans.
I think it is abundantly clear we should make every effort to keep our hummingbird feeders as clean as possible.
Most of us have been taught that birds do not eat monarchs. In fact, if a bird just happens to try to make a meal out of a monarch, it gets sick from ingesting the poisonous compounds that course through the monarch’s body. After living through such an experience most birds do not try to dine on a monarch again.
Eastern bluebirds are an exception to the rule. These gorgeous backyard favorites eat monarch caterpillars laden with poisonous chemicals obtained when they chomp on milkweed plants without showing any ill effects.
The bluebird can devour this toxic food because it uses a technique to prepare a caterpillar before it tries to consume it. Once a bluebird grabs a monarch caterpillar it flies to a branch and squeezes the large, juicy caterpillar time and time again. This process forces much of the juicy innards of the caterpillar out both ends of its body. Once the caterpillar has been flattened, the hungry bluebird then proceeds to eat the hapless insect.
Now that September has arrived it is hard not to turn our thoughts toward fall and migration. Invariably we associate migration with birds. However, the plight of the monarch has heightened our interest in the migration of insects such as the monarch butterfly.
Each fall these amazing insects make their way south to their winter home in Mexico. While this is truly an amazing fete, we know very little about how these butterflies accomplish this seemingly impossible task. Recently the results of research conducted by Samantha Knight of the Nature Conservancy of Canada and others filled in another piece of the jigsaw puzzle of monarch migration.
The research team captured and placed tiny transmitters weighing only 300 milligrams on 43 monarch captured near the Canadian shore of Lake Huron. The devices were mounted on the insects in an attempt to track their southbound migration. Fortunately, the biologists were able to retrieve data from six of these butterflies. One of the most interesting findings was one of the monarchs flew 89 miles in a single day. They were also able to determine the monarchs winged their way south at a speed on 7.5 miles per hour. Knight later stated, “[It] was a lot faster than anyone had ever really anticipated.” She went on to comment, “They could likely go even faster without the heavy tags on them.”
The biologists also learned the butterflies flew faster when they were pushed along by a tailwind. This was demonstrated by one butterfly that was clocked flying at a bit under 18.5 miles per hour with the aid of a tailwind.
It was also discovered that monarchs flew faster in warm weather. However, the butterflies were not able to fly until the temperature reached 50˚F and flight speed dropped when the air temperature reached 73˚F.
It is definitely true the more we learn about these stunning insects the more we realize why they are so special.