Did You Know This About Birds?

Bird Trivia by Dan Gleason?

#1 — Observed rate of flicker in birds

Birds have the ability to see higher flicker frequency rates or cycles per second. Imagine turning a light on an off. The faster you turn it on and off the higher the flicker frequency rate. A fluorescent lamp flickers at a rate of about 60 cycles per second (cps). The human eye is only capable of seeing a rate of 50-55cps, thus the fluorescent light looks continuous because it is flickering faster than we can detect (unless the light slows as it ages and we sometimes become aware of it). Some birds can see flicker rates of over 100cps. The faster we move, the more nearby objects, such as branches, become blurred. The could be a problem for fast-moving birds were it not for the faster flicker frequency rate. A Sharp-shinned Hawk, in quick pursuit of prey through dense woodlands can clearly see and avoid the branches in its path. Just one of the many ways birds’ vision is superior to that of humans.


#2 — Number of feathers on a bird

Over the years, naturalists and researchers have counted the total number of feathers on various species of birds, and the counts range from a low of 940 feathers on a Ruby-throated Hummingbird to a high of 25,216 on a Tundra Swan. Most songbirds have 1,500–4,000 feathers. The greatest concentration of feathers on most birds is around the head and neck, and, in most songbirds this amounts to 30–40% of the total number of its feathers.


#3  — The size of birds

The smallest bird in the world is the Bee Hummingbird, Mellisuga helenae, found only in Cuba. It weighs just 1.6 grams, about 3/4 the weight of a dime. The Anna’s Hummingbird that frequents our skies weighs about 2.75x more than the tiny Bee Hummingbird!

The largest living bird (by weight) capable of flight is the American White Pelican, Pelecanus erythrorhynchos, which has been recorded  weighing up to 30 pounds. The Trumpeter Swan, Cygnus buccinator, is a close second with adult males weighing over 26 pounds.

The largest living flying bird (by wingspan) is the Wandering Albatross, Diomedea exulans, with a wingspan of about 12 feet and a weight that may reach 26 pounds, although 23-24 pounds is more typical.

You might already know that the largest living bird is the Common Ostrich, Struthio camelus, of Africa. Males can stand nearly 9 feet tall and weigh up to 320 pounds.

The largest bird that ever lived is the extinct Elephant Bird, Aepyornis maximus, of Madagascar. It stood over 10 feet high and weighed up to 1,600 pounds. Its egg was over 13 inches long and held about 2 gallons in volume. It became extinct about 1,000 years ago, probably because of human activity.


#4 The Bobolink — A long-distant Migrant

The Bobolink, a member of the Blackbird Family, is common in the grasslands of southern Canada and the northern United States. In Oregon, it is found at Malheur National Wildlife Refuge and a few other locations in eastern Oregon. It is a remarkable long-distant migrant, one of the longest migrations of any songbird. Each year it flies from its breeding grounds in North America to Bolivia and Argentina south of the equator—a distance of about 12,500 miles round-trip. Some birds have been known to live up to 10 years making their lifelong mileage over 125,000 miles per individual—a distance more than 5 times around the world at the equator! To navigate, they use the stars and cues from the Earth’s magnetic field.






#5 The Fastest Bird — Peregrine Falcon

The fastest bird in the world is the Peregrine Falcon. It has been clocked at a speed of 240mph in a power dive. The Golden Eagle is a close second with speeds of over 200mph in a dive. The fastest bird in direct powered flight is the White-throated Needletail, swift of SE Asia and Australia. It has been clocked at a speed of 105mph.










#6 Ducks — How They Find Food in Muddy Water

An unguis is a nail or claw. In ducks, it refers to the nail-like structure on the tip of the bill. This structure is densely packed with sensory cells for touch. These sensory cells are able to discriminate a far lighter touch than other birds or mammals can; a much lighter touch than humans can feel with our fingertips. This helps ducks find food items in muddy water by touch rather than relying on visual cues.

#7 — Pterylae

The feathers in birds grow in defined tracts on the skin over the body. These are called pterylae. There are 8-10 major tracts that can be further subdivided into smaller tracts. The bare regions between these tracts are called apteria. All birds have these tracts except penguins where the feathers are uniformly distributed over the body. There is actually evidence of feather tracts embryonically in penguins but they disappear before the embryo hatches. Even in close-up photos of birds, such as this photo of a Northern Flicker, feather tracts cannot be seen.

An interesting, but unrelated fact, woodpeckers do not have true down feathers.

#8 — Heart Rate in Birds

 The heart in birds is larger than in comparable sized mammals. The larger heart of a bird pumps more blood per heartbeat than does that of a mammal, and birds at rest typically have a slower heartbeat than a similar-sized mammal. Activities such as flight quickly elevate the heart rate, and small birds have a more dramatic increase in heart rate with exercise than do large birds. A large gull may go from 150-200 beats per minute while at rest to over 600 beats/minute during flapping flight. Hummingbirds may go from a resting heart rate of 500 beats per minute to over 1200 heartbeats per minute while flying. At night a hummingbird goes into torpor and the heart may drop to 40 beats/minute.




 #9 — Eagle Eyed

 Do eagles really see 7X better than we do? Well, that depends upon what you mean by better. Eagles, and other birds of prey, do see an object that is 7X larger than we do. The difference is in resolution. In the central part of the eye (macula is the term used in humans and fovea is the term used for birds and most other animals) will be found the highest number of cones. Cones are responsible for color and sharpness. We have approximately 200,000 cones per square millimeter. Eagles have over 1,000,000. Think of it as similar to pixel on a computer screen—the more pixels, the higher the resolution and the sharper, more detailed the image. If you look at a barcode of a grocery store item from across the room, you probably can’t see the lines clearly. If you simply magnify it the image will be bigger but just as fuzzy. The eagle can still “resolve”, or clearly see those lines across the room with magnifying them. It’s not just eagles and raptors that have this ability, Swifts and swallows need to see flying insects while flying fast themselves and flycatchers need these visual skill to see their prey.


 #10 — Bird Ovaries

In most birds the females have only one functional ovary and oviduct, usually the left one. The right ovary and oviduct typically degenerate early in embryonic development. Eggs nearly ready to be released from the ovary, contain the yolk material. When an egg is released from the ovary, it typically takes only one day for the egg to travel down the oviduct, acquire albumen and additional materials added. Once it reaches the uterus at the end of the oviduct (a process that takes 4-5 hours) a shell put on to surround the egg and make it ready to be laid. This takes about 20 more hours. The egg will then turn and be pushed from the body large end first.

If both ovaries and oviducts were functional and contained mature eggs, the females of many species would have great difficulty, or even be unable to fly until unburdened of one or even both eggs. This situation actually occurs in some steamer ducks that are nearly unable to fly even without the weight of an egg and cannot fly for a day or two while carrying a mature, unlaid egg.


#11 — Some Birds Eat Ash

 Some birds have been seen at ash pits. Look closely if you see this behavior. Maybe they are searching through the ashes for insects, but maybe, they are actually eating some of the ash.

Strange as it seems, hummingbirds, especially in the southwest, will sometimes eat ashes. This seems like an odd diet for a hummingbird. It is always the females in most species that eat ash, rarely do males do so, and other species of birds eat ashes as well

Ash is high in calcium and eating ash is a quick way to help return lost calcium. Why females? To produce a clutch of eggs, females often become deficient in calcium used to produce the shell.They often even deplete some of the calcium in their own bones. Eating bits of eggshell fragments or the fecal sacs of the young can provide a quick way to obtain some calcium, but charcoal is also a possible source. Campfires that are heavily doused with water may leach out the calcium into the surrounding soil but fires allowed to extinguish naturally are usually higher in calcium. This was the findings from a study done on Boreal Chickadees in Newfoundland in the 1980s. In that study, the Boreal Chickadees ignored ash pits with low calcium content.

Crossbills have a different reason for eating ash and in crossbills, males also eat ash. These birds may feed on ashes more than any other North American bird. Crossbills feed on conifer seeds by prying open young cones. The immature seeds that they feed on have not yet dried and are still somewhat resinous. This sticky resin can cause digestive problems. To help moderate this problem and facilitate digestion, crossbills eat from clay deposits and charcoal where available. This helps absorb some of the resin, allowing the birds to digest the seeds more easily.

An interesting related behavior is observed in some macaws in South America. Their massive bill allows them to feed on the seeds of some trees that other birds cannot eat. Some mammals may have the teeth to break apart these seeds but ignore them because they contain compounds that are mildly toxic. (Or in the case of the liana tree, very toxic. Those seeds contain strychnine.) The macaws feed on these seeds with immunity, but only for one reason—After eating these seeds, they fly to areas with large exposed clay deposits. Again, their large beak assists them in obtaining large amounts of clay that they readily consume. The clay absorbs the toxins awhich are then passed out of the body harmlessly.


#12 — Deep Forest Voices

 Some birds, like some owls, have deeper-pitched voices than other similar birds. Is this just happenstance or is there some reason for this? In owls, those that live in dense forests have deeper voices than owls that live in open country.

Sound carries relatively well in open country but is quickly absorbed by vegetation of forests and bushes. Lower frequencies travel farther, even in dense vegetation, than do higher frequencies. So, Great Horned Owls, Spotted Owls, and other. forest-dwellers all tend to have low voices. If there is a need to hold a large territory, the voice may be even lower to reach a longer distance. Flammulated Owls are small, yet they have very low voices. Their territory is quite large. larger than similar-sized Screech-Owls, and their voice is lower, traveling a longer distance into the woods. The male is the one who most defends the territory and his voice is lower than that of the female, even though she is larger is size.

Other birds, like Sooty Grouse, also have very low voices. These grouse are generally solitary birds and when the time comes to attract a mate, they must attract the attention of females who may be at a considerable distance from them. The first method of attraction is by voice and the very low voice of Sooty or Spruce Grouse carries a long distance through the forest.

Of course, not all forest-dwellers have low-pitched voices. Pacific Wrens have a long high-pitched song. The voice is quickly absorbed by the vegetation, but the wren has no need for its voice to travel far. It holds a small territory and its high voice is very effective for its needs. His neighbors can hear him well and there is no need to be heard by distant wrens.

Low frequency sounds travel far but can be difficult to locate. High frequency sounds are quickly absorbed by leaves and other vegetation but are easily pin-pointed. Golden-crowned Kinglets make high-pitched vocalizations as they travel through the conifers, high above the ground. Such high sounds don’t travel far to attract the attention of others, but they help with flock integrity, allowing each bird of the group to easily locate their neighbors and stay together.


#13 — Very High-Altitude Flying of Birds

 The Bar-headed Goose of Asia, migrates at high altitudes. It can fly over the highest parts of the Himalayas, including over the summit of Mt. Everest. By doing so, it can take advantage of the jet stream and reach flight speeds of over 90 mph allowing completion of a 400-600 mile journey in a single day and avoid a multi-day journey at lower elevations around the mountains. Even Mallards have been recorded flying over 21,000 ft. in altitude and a Golden-crowned Sparrow was struck by a small plane at 10,000 ft. To fly over 20,000 ft. means that the birds encounter an air pressure that is less than ⅓ of the pressure found at sea level and temperatures are nearly -60°F. To survive, special adaptations are needed. Birds that fly at high elevations often have two forms of hemoglobin, the oxygen-carrying molecule of the blood. The second form of hemoglobin is able to capture and release O2 with greater efficiency at high altitudes and this form is equal to or is more concentrated in the blood  than the “normal” form in such high-flying birds. Additionally, because oxygen is at lower concentrations at high altitudes, the birds must breathe faster, and the exertion of flying increases the breathing rate even more. This causes the carbon dioxide (CO2) to become more concentrated in the blood which increases the pH of the blood (making it more alkaline). The normal pH of the blood is 7.3-7.4. In this very high-altitude flying, the blood of these birds may reach a pH of 8.0, a condition that would be fatal to humans. No one yet knows how these birds survive such extremes of pH, but all of these marvelous adaptations allows the annual migration of these geese to be possible.


#14 — Staying On A Perch

How does a bird perch on a twig without becoming unbalanced? Even more curious, how does a bird sleep on a perch through the night without falling off? It seems like the muscles must get tired gripping tightly through the night. In fact, the muscles don't need to do any work at all. A special arrangement of tendons helps hold the foot securely.

When looking at a birds foot, many people assume that the knee bends backwards as compared to our knee. But that rear pointing joint is actually the ankle and what we think of as the birds’ foot, is just its toes. In a bird, the long bones between the ankle and toes are fused together and elongated into one long bone. The knee works the same as ours, but it is usually hidden from our view by the body’s feathers. The muscles of the leg are above the knee. A tendon runs from these muscles down the length of the lower leg, wraps around behind the ankle, extending to the toes, and branching out underneath the bones of each toe. As the bird sits upon a perch and the ankle bends, this tendon is stretched. In doing so, the bones of the toes are pulled together and curl around the perch, holding the bird tightly in place. Additionally, in songbirds, the tendon is wrapped in a sheath which has tiny ridges along its length. These ridges match corrugations in the tendon. As the weight of the bird pushes down against the perch, the corrugations of the tendon interlock with the ridges of the sheath and this prevents the tendon from sliding in its sheath as the bird sits on the perch. With this adaptation, the muscle does no work and the bird easily sits in place without concern of falling off. As the bird takes flight, it pushes upward, releasing this locking mechanism and relaxing the tendon, making it easy to release from the perch. It should be noted that a bird can voluntarily open its foot anytime it wishes while perched, but this adaptation makes sitting on a perch easy to do without the need to constantly grip it.