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HOW MANY WORMS CAN A ROBIN EAT?

       We are all familiar with the old tongue twister that goes something like this, “How much wood would a woodchuck chuck, if a woodchuck could chuck wood?”  When I was a young boy I often wondered how much wood that would be.  Long ago I stopped wondering the answers to such whimsical questions.  Nowadays, I am intrigued by other mysteries such as how fast can a bird fly and how much food can a wild animal consume.  For example, I have long wondered how many earthworms an American robin can devour in a single day.

       Earthworms are an important component of the American robin’s diet. In fact, roughly 40 percent of the bird’s diet is comprised of earthworms.  Many of these earthworms are captured in our yards.  In fact, seeing a robin pulling a long worm out of the ground is a familiar sight in many yards across the state.

       As it turns out, robins are exceptionally skilled at hunting earthworms.  Remarkably robins have been found to capture upwards of 20 earthworms an hour. Another way to look at the American robin’s ability to pluck these slimy critters from the ground is illustrated by the fact that a single robin can eat up to fourteen feet of earthworms per day.       Wow!  I am impressed. 

THE HUMMINGBIRD’S ABILITY TO SELECT NECTAR-RICH BLOOMS

       August is a special month for both ruby-throated hummingbirds and those of us that enjoy watching them.  Throughout the entire month, the number of hummingbirds visiting our feeder swells as they voraciously feed on the nectar provided by our feeders and flowers.  The reason for this increased activity is these flying jewels must quickly eat enough food to enable them to store the fat required to fuel their long journey to their winter home.

       In order to accomplish this task, hummingbirds make frequent feeding forays to our feeders and as many flowers as possible.  Since hummingbirds have one the highest rates of metabolism known, they expend huge amounts of energy trying to prepare for their arduous migration.  Obviously, anything that makes this task more efficient greatly benefits these flying dynamos.

       One way the birds would be able to streamline their feeding binge would be to possess the ability to avoid visiting flowers that harbor little or no nectar.  Well, as amazing as it may seem, they can do just that.  Here is how it works.

       The amount of nectar produced by each nectar plant varies considerably throughout the day.  A number of variables such as soil moisture and weather conditions affect it.  When hummingbirds, butterflies, bees, wasps, and other nectar feeders consume nectar, it takes time for it to be replenished.  This time varies considerably.  For example, some flowers do so only once a day, others every half-hour, others varying amounts of time in between.

      Ruby-throated hummingbirds have the ability to learn how long it takes a flower to rejuvenate its supply of energy-rich nectar.  Consequently, when a rubythroat visits the zinnias, salvias, lantanas, bee balms, trumpet creepers, and the like growing in our hummingbird gardens they rapidly learn how long it takes each plant to produce a new crop of nectar.  Only then will they revisit a plant it fed at earlier in the day.  This eliminates the need to revisit the plant until correct amount of time has elapsed.

       This astounding ability has been demonstrated by researchers such as a team of University of Edinburg biologists.  Their experiments involved providing hummingbirds with two groups of artificial flowers laden with nectar.  One group of flowers was refilled with nectar every ten minutes.  The second group was replenished every 20 minutes.  In short order, the hummers learned when each group of flowers provided them with a source of food.

       Keep this in mind as you watch the hummingbirds visiting various flowers about your yard.  It will help you better understand why they feed at certain nectar plants when they do.  If you are like me, you will come away being even more impressed with a bird so small, ten could be mailed for the price of a first-class letter.

MOCKINGBIRDS DON’T LIKE TO SHARE

     Northern mockingbirds are common backyard residents throughout Georgia.  Unlike some of the birds, we see in our backyards, it is a permanent resident.  If you regularly see or hear a mockingbirds in your yard, it is safe to say your property is located within a mockingbird’s territory.  This means a mockingbird will try to keep other birds from its favorite food sources such as feeders.  Currently a mockingbird is defending my suet feeder.

       Consequently, the only time hairy and downy woodpeckers, cardinals, house finches, Carolina chickadees, brown headed nuthatches, tufted titmice and others an able to feed on the suet offered in a wire suet feeder is when the mockingbird is somewhere out of sight of the feeder.

       The only bird that doesn’t seem to be intimidated by the mockingbird is the brown thrasher.  I have never witnessed a mockingbird try to scare a brown thrasher away from a suet feeder; perhaps this because mockingbirds find thrashers too large and intimidating.

       Since I enjoy watching a variety of birds feeding in my feeding area, I have tried a couple of things remedy the situation. 

              MOCKINGBIRD AT SUET FEEDER

       For example, I purchased a suet feeder that was surrounded by hardware cloth cage. The suet feeder was positioned well away from the side of the cage.  While it allowed smaller birds such as brown-headed nuthatches, titmice, chickadees, and sparrows to slip through the opening in the hardware cloth and feed, it kept larger birds such as mockingbirds, cardinals, and woodpeckers away.

       My latest approach is to offer my backyard avian neighbors two suet feeders.  The theory is that it is impossible for one bird to defend more than one feeder.

       I began my experiment by placing another suet feeder within ten feet of the original feeder.  It didn’t take long for me to realize there the second feeder was positioned too close to the original feeder.  As such, the mockingbird kept other birds away from both feeders.

       I have since moved the second feeder some 30 feet away.  This seems to work fine, however, I now find it more difficult to watch and photograph birds visiting the second feeder.  That being the case, I need to begin moving the second feeder ever closer to the first feeder.  I am sure; at some point, the mockingbird will be able to defend both feeders.  Then I can move it back to a location just beyond that distance.

       Perhaps I do should go ahead a let the mockingbird defend a single suet feeder.  Since the bird cannot be near the feeder all of the time, I can enjoy seeing other birds dine to the suet during those times the mockingbird is elsewhere.  That may be best after all.   

       If you have come up with a great way to deal with an aggressive mockingbird trying to defend suet, mealworms, or fruit, I sure would like to know about it.

IN SUMMER, YOUNG BIRDS ARE OFTEN TOUGH TO INDENTIFY

        Now that we are well into summer our backyards are inhabited by birds that either breed locally and their newly fledged young. We are all familiar with the adult cardinals, robins, bluebirds, and towhees that we see every day. However, when their young begin visiting our birdbaths and feeders, it is often difficult to identify them. As such, some of these birds make us wonder if we are looking at a new addition to our backyard bird list or the young of a one of our summer residents. Below you will find some tips that can be used to recognize the young of some of our common backyard residents.

Eastern Towhee – Young towhees have the characteristic towhee shape. However, these youngsters have a definite brownish plumage. Unlike their parents, though, their undersides are streaked. This gives them the appearance of a large sparrow. In spite of this, they will be adorned with the same white feather pattern on their wings and corners of their tails seen on their parents.

 

American Robin – Juvenile American robins look like faded versions of the adult female robin. They differ, though by featuring white teardrop spots on their backs. The breasts of young robins seem to be bathed in reddish-brown and covered with distinctive dark speckles.

Northern Cardinal – Whenever I see an immature cardinal, it seems it has a bedraggled appearance. They too resemble their mothers; however, their plumage is dull brown. Often their tails and breasts will seem as if they have a faint reddish wash. Their bills are always blackish.

Eastern Bluebird – Young eastern bluebirds are not blue. Instead, they are light brown in color. The topside of their bodies will display pale white spots. The young birds’ breasts are covered in speckles that give them a scaly appearance.

       I hope these tips will help you identify some of the birds you are currently seeing. Keep in mind, as fall approaches, bird identification will become much more worrisome when the confusing fall warblers and other Neotropical migrants begin stopping in our backyards en route to the winter homes.

BACKYARD SECRET — THE CHIMNEY SWIFT HAS A VARIED DIET

       The chimney swift eats a large variety of insects and other invertebrates. Its diet includes the likes of ants, caddisflies, bees, wasps, and beetles. Some of the more unusual critters regularly consumed by what some folks call “flying cigars” are fleas, airborne spiders, termites, and even fire ants.

       It has been estimated that a pair of chimney swifts feeding three nestlings captures the equivalent of 5000 to 6000 fly-sized invertebrates per day.

WHEN DO BACKYARD BIRDS BATHE?

       My wife and I maintain three birdbaths for the benefit our backyard bird neighbors. As you might expect, many factors such as season and weather influence when and how often birds use these manmade structures.

       Although birds bathe in the winter, they often limit their bathing during frigid weather. On the other side of the coin, many species seem to increase their visits to birdbaths during hot weather.

       A number of years ago, I happened across several wood thrushes bathing in a puddle that had formed in a country road during a sudden summer thunderstorm. To this day, I still wonder why these beautiful songsters chose to bathe immediately after the passing of the storm.

              In addition, birds also seem to be influenced by the presence or absence of other birds. My personal observations suggest that some species seem to prefer to bathe alone, while others do not mind sharing a bath with other species. For example, when a mockingbird or blue jay flies in to take a bath, other species that are already bathing immediately scatter. It is obvious that they do not wish to bathe at the same as these larger, more intimidating birds. More often than not bathing chipping sparrows will leave when eastern bluebirds arrive. However, I have seen chipping sparrows bathe alongside house finches.

       By the same token, birds of the same species often have no problem bathing with others. Northern cardinals often bathe together as do eastern bluebirds.

       Birds can be seen bathing throughout the entire day. Some birds seemingly bathe immediately after leaving their nighttime roosts. By the same token, others appear to bathe just before flying up to roost for the night. In between, most birds are not hesitant to take a bath any time during day.

       For some reason, I long harbored the notion birds bathed but once a day. I have no idea why I felt that way. However, studies involving color-marked birds have revealed that some species such as the tufted titmouse sometimes bathes as many as five times a day.

       As you can see, we have much to learn about bird bathing. In an effort to quench my personal interest in this behavior, I have begun recording information regarding incidences of birds bathing in my yard. I guess that is the biologist coming out in me.

 

 

 

 

 

 

 

 

GOLDFINCHES ARE ATTACKING ZINNIA BLOSSOMS

        In my August 2, 2019 blog, I reported how American goldfinches ravaged the blossoms displayed by the zinnia plants growing in the large containers set on our deck. Watching the beautiful birds plucking the petals off the flowers and then gorging themselves on the seeds nestled at the base of the petals was so entertaining we were hoping the birds would return for another performance this year. Last week my wife found red zinnia petals littering the floor of the deck. Much to our delight, the birds have returned.

         In 2019, we first observed this behavior in late July. It is interesting to note that this year my wife discovered the unmistakable evidence of the birds’ activities late in June. We cannot help but wonder why the birds are visiting the flowers so much earlier this year.  

         In addition, another mystery has emerged. While red, pink, white, and orange zinnias are blooming in the same containers, so far the birds are only eating the seeds of the red zinnias. Is this a coincidence? Who knows?

         If zinnias are currently blooming on your deck or in your garden, keep your eyes peeled for zinnia petals scattered beneath the plants. If you find them, chances are, if you closely watch the plants, you will be able to witness this fascinating behavior.

         If you don’t have zinnias growing in your backyard, it is not too late to plant some. Zinnias have plenty of time to blossom and provide goldfinches with a late summer banquet.

IS THE RED-TAILED HAWK A THREAT TO FEEDER BIRDS?

      Recently while I was standing in the yard of my home, I spotted a red-tailed hawk gliding across my front yard. A northern mockingbird trailed the hunter. As I stood motionless, the hawk slowly descended before finally flaring its rusty-colored tail and landing out of sight just beyond the trunk of a water oak tree. Apparently, the red-tail missed its target as it immediately rose up without anything dangling from its talons and flew toward the back of my yard. As I stood spellbound watching the wild drama play out, the aerial hunter disappeared from sight, with the mockingbird still trailing close behind.

       Whenever a hawk appears in our yards, we often assume it is a threat to the birds using our feeders. If such is the case, is this assumption correct?

       While I did not see what the red-tail I was trying to catch, the evidence suggests, in this case, it was a mammal and not a bird. I never did see a bird fly away. However, eastern chipmunks and gray squirrels are regularly seen around the tree. If the hawk was pursuing a chipmunk, the small mammal could have escaped into a burrow. Whereas, a gray squirrel could have sought refuge climbing up the trunk of the tree.

       Studies of the red-tailed hawk’s food habits suggest that I could be right. When biologists evaluated the results of 27 food habit studies conducted on red-tailed hawks in North America, they found mammals made up the bulk (65.3%) of the 500 prey species that showed up in the diets of the birds examined. Birds were the second most important food item. A little more than 20% of the predator’s diet consisted of birds.  

       Rodents and rabbits proved to be the mammals most often eaten. Rabbits and hares proved to be the most important mammals in the diet. However, gray and fox squirrels, chipmunks, ground squirrels, and rodents such as voles, mice were eaten too.

       The list of other animals consumed included reptiles, invertebrates, amphibians, and fish.

       Although some 200 species of birds were recorded in the 27 surveys, the species most often taken by red-tails were pigeons, doves, European starlings, and woodpeckers. The woodpecker most frequently captured by this hawk was the flicker.

       Based on these findings the argument could be made that the red-tailed hawk is not a significant threat to the birds that commonly dine at our backyard bird cafes.

BACKYARD SECRET–PURPLE MARTINS HELP CONTROL FIRE ANTS

       Purple martins are known to eat at least 79 species of insects including dragonflies, flies, bees, moths, and butterflies. However, I would be willing to guess you did not know they also dine on fire ants.

       It seems purple martins target mating male and queen fire ants. One group of researchers studying the feeding habits of purple martins found fire ants were captured during 32 percent of the birds foraging trips. The ants accounted for 31 percent of the insects taken. In addition, fire ants comprised 27 percent of the biomass consumed by the birds and their young.

       Based on these data, the scientists estimated purple martins consume some 1.7 billion fire ants annually across the United States.

THE SUMMER TANAGER’S ODD FOOD CHOICE

       One of the many birds that inhabit our backyards during the spring and summer is the summer tanager. Although it is one of our most beautiful backyard residents, it is a bird that lives there in relative anonymity. This is because it rarely visits our feeders and regularly feeds out of our sight within the thick canopies of tall, leafy trees. If we were able to peel away the leaves and watch a summer tanager feed, we would be soon discover that this striking bird has an odd food preference.

       Like a number of our other summer avian residents, the summer tanager dines on a wide variety of foods. Its varied diet includes fruits and berries in addition to a host of various invertebrates such as grasshoppers, cicadas, spiders, moths, and butterflies. However, the thing that separates the tanager from many birds is its affinity for bees, hornets, and wasps. In fact, it is so fond of them it is sometimes called the bee bird.

       Remarkably one of the bird’s favorite foods is the paper wasp. Summer tanagers are known to eat the adult wasps and also rip open their nests and feast on the wasps’ larvae.

       More often than not, we rarely catch a glimpse of a summer tanager hunting for insects that can deliver a painful sting to bird or man alike. From time to time though, summer tanagers can be seen perched closer to the ground near a beehive waiting for the chance to snatch a worker honeybee flying to or from the hive.

       The summer tanager is able to avoid being stung by grabbing hold its prey and flying back to a nearby perch. Once there it pounds the hapless insect against the branch until it is dead. It then proceeds to wipe the lifeless insect on the branch. This removes the bee’s stinger and other body parts that are inedible. Once this food preparation is completed, it swallows the bee whole and awaits the chance to feed again.