Bird talk, music to our ears

The “cheer up, cheerily, cheerio, cheerily” of the American robin fills the air at the crack of dawn. A musical chorus ensues and tapers before sunrise. 

Songs range from high to low pitched, long to short and simple to complex. Bird songs are unique to each species and generally only passerines (songbirds) sing.

Birds begin to sing songs in spring and continue into summer. The two main reasons birds sing are to defend territory and to attract mates. With those purposes fulfilled, a bird stops singing or reduces his singing greatly.

Males generally sing the songs, but females of a few species also sing, such as the red-winged blackbird. 

Songs differ from calls. Both males and females call for alarm, to locate a mate, advertise food or to keep a flock together. A familiar call is that of the Canada goose during flight.

A song sparrow sings from an elevated perch

All vocalizations of birds originate in an organ unique to birds, the syrinx. The syrinx is similar to the larynx in mammals. Located at the first major branching of the windpipe (trachea), the syringeal muscles control membranes that restrict the air flowing through the tubes. When air is forced through the trachea, the thin membranes vibrate and produce sound.

Birds unable to use their syringeal muscles, such as turkey vultures, have limited vocalization. Birds with a complex musculature of the syrinx tend to produce a variety of bird songs. A brown thrasher can sing over 2,000 different songs.

Song complexity is not directly related to syrinx complexity as the Corvidae family   demonstrates. Even though crows and jays have a complex syrinx, they are not great singers. However, they produce an impressive variety of sounds that are not considered musical. 

With the location of the syrinx at the junction of the trachea, a bird can produce two sounds at once or breathe air in one side while the other produces sound. 

Each species produces a song that transmits the best in its environment. Birds of wetlands tend to sing from elevated perches to minimize the interference of vegetation. 

In the forest, interference is everywhere and birds adjust their pitch accordingly. Birds in the tree tops sing high-pitched songs because tree trunks don’t interfere with broadcasting. Birds residing in the understory sing low-pitched songs because a lower pitch travels through obstacles better. 

With the background noise of streams and waterfalls, an American dipper sings a loud, ringing song so it can be heard. 

A western meadowlark sings at dawn

Birds also know the best time to sing their song, which is typically morning. Before dawn the air tends to be still and there are fewer competing noises. A few birds sing during the day, at night or in the evening. 

While each species has a signature song, there are individual variations. Often males are chosen by females because of their extensive song repertoire. 

Others, such as the American robin, sing variations of the signature song. The song has all the same components but they are sung in a different order, enabling others to distinguish individuals when they sing a version of “cheer up, cheerily, cheerio, cheerily” at dawn and dusk.

Note: Published in the Bonners Ferry Herald on May 30, 2013.

Conifers increase the odds with prolific pollen

You may have noticed a yellow dust on your car or around the edges of puddles recently. The visible yellow dust is only a fraction of the pollen that is being released from conifers. 

Spring is a time for pollination and conifers are no exception. Conifers are subtle in their pollination since they don’t produce flowers. Instead, pollination and seed development occurs in cones. 

Brown “pine cones” are what first come to mind, but they are actually the end product. Conifers produce two types of cones: pollen cones and seed cones. 

Seed cone (top right) and pollen cones (lower left) on a small lodgepole pine

Pollen cones are small and often fall off the tree once the pollen has been dispersed. Pollen cones on pine trees cluster at the base of new shoots (called candles) and are fairly visible now. 

Since wind helps pollinate conifers, each pollen cone releases an astronomical amount of pollen--up to two million grains per pine or spruce cone--to ensure that at least one pollen grain lands on an ovule in the seed cone.

Ponderosa pine pollen cones at base of new growth (candle)

The seed cone is where fertilization and seed development takes place. To increase the likelihood of seed production, the seed cones often form on the uppermost branches where they are exposed to more wind-blown pollen. 

Pollen cones are typically located below the seed cones to prevent self-pollination. However, seed cones can chemically recognize pollen from the same tree and will not accept it. 

Initially seed cones can be as small as the pollen cones and can be hard to locate, but they grow with seed development. Each seed cone, for the most part, consists of numerous scales with ovules between the scales. The ovule develops into the seed. 

Fleshy yew and juniper seed cones resemble fruit more than a woody cone, but they are conifers because of the naked seed. All conifers are gymnosperms, which means that the seeds are not enclosed by fruit at maturity.

Some conifers, such as cedar, develop seed in one growing season. Others, such as pines and Douglas-fir, require two growing seasons to develop seed with rapid enlargement of the seed cone the second summer. 

Close-up of lodgepole pine seed cone at tip of candle

For pine seed cones that are pollinated this spring, fertilization will occur next spring. The movement of the pollen grain from the outside of the ovule to the inside takes over a year. 

Typically once the seeds are mature, the cone changes color from green to brown, the scales of the seed cone spread apart and the seeds fall out. Lodgepole pine cones remain closed when mature and require fire to melt the resin and release the seeds. 

Immature grand fir cone

The size of the seed is determined by how it is disbursed--wind or animals. Seeds dispersed by wind, such as Ponderosa pine seeds, are small and have wings whereas animal-dispersed seeds, such as whitebark pine seeds, are larger with no wings. The average weight of Douglas-fir seeds is approximately 40,000 per pound.

Some seed cones fall off the tree when the seeds are mature, others stay on the tree and disintegrate. Black spruce cones remain on the tree for 20 to 30 years. 

Whitebark pine cones disintegrate on the tree before dispersing seeds but animals, such as Clark’s nutcrackers and squirrels, usually harvest the seeds first. 

Conifers produce astronomical amounts of yellow pollen and prolific amounts of seed to increase the likelihood that a least one seed will germinate and continue the cycle.

Note: Published in the Bonners Ferry Herald on May 23, 2013.

Busy as a bee no understatement

From the moment they pupate into an adult until they die, honeybees are constantly working. Truthfully, it is the females who work constantly. 

Three types of honeybees live in a hive--a queen, worker bees and drones. Drones exist to mate and are expelled from the hive during winter. 

Worker bees collect all the pollen and nectar for the hive

 For the two to five years a queen lives, she mates and constantly lays eggs. A queen can lay up to 100 eggs an hour and over 200,000 eggs in her lifetime.

Fertilized eggs will produce females and unfertilized eggs will produce males (called drones). The majority of fertilized eggs produce worker bees, which are sterile females. If a larva is given special treatment, it will turn into a queen bee. 

Honeybee workers exhibit “age polytheism” which means their behaviors change as they get older. A worker bee first starts by cleaning cells. Then it moves onto other hive maintenance, fanning the cells to maintain air circulation and temperature (94 degrees Fahrenheit average), and processing nectar. 

At the end of the first week, workers start producing “royal jelly” from two large glands on their head. The protein-rich fluid is fed to the larvae, queen and drones. A queen is fed royal jelly her entire life. This special treatment enables her to turn into a queen versus a worker bee. 

In a worker bee’s second week of life, her wax glands start producing wax to build and repair the hexagonal comb in the hive.

During the third week, the royal jelly and wax glands atrophy and she shifts to foraging. As a forager, the average lifespan is 10 days in the summer. 

Honeybees have pollen baskets on their hind legs to carry pollen back to the hive

In one day, a honeybee can fly up to 12 miles and visit 10,000 flowers. Typically a forager will stay within three kilometers of the hive. The collected nectar and pollen is brought back to the hive to feed other workers and for winter storage.

Honeybees hone in on flowers by scent and visible clues. Bees are able to see markings on flowers only visible with ultraviolet light.

Nectar is brought back in the honeybee’s crop and regurgitated with enzymes into cells. Then younger worker bees fan the nectar to evaporate the water. When deposited into the cell, the nectar is 80 percent water. After evaporation to 16 percent water, the nectar is referred to as honey.  

In a forager’s lifetime, she will bring back enough nectar to make about half a teaspoon of honey. To make one pound of honey, foragers have to visit about two million flowers. 

The life of a honeybee lasts from 35 days to several months depending on the time of year it was born (bees born in winter can live longer). 

Sometimes a forager’s life is shortened when she stings. The barbed stinger is torn away from the body when used, thus killing the honeybee. Other bees become instantly alarmed when the stinger is torn away because it releases an alarm pheromone that helps other bees locate the enemy.

Worker bees use their tongues to slurp up nectar

Many introduced species don’t have enemies, but bees do have enemies including certain spiders, wasps, birds, bears, skunks and people. Honeybees are not native to North America or South America. They were brought over from Europe by colonists to both coasts (as they couldn’t cross the Rocky Mountain themselves). 

Capitalizing on the abundance of flowers in the summer, honeybees have stayed busy for centuries collecting food for themselves, pollinating flowers and setting a precedence for being as busy as a bee. 

Note: Published in the Bonners Ferry Herald on May 16, 2013.

Crane flies resemble over-sized mosquitoes

Mosquito eaters, skeeter eaters and mosquito hawks are a few names for a gangly insect that looks like an over-sized mosquito. However, these names really aren’t representative of crane flies--especially since the winged adults don’t eat mosquitoes.

Adult crane flies don’t actually eat anything at all and if they do it is nectar. The nicknames come from their appearance and the possibility that when larvae they eat mosquito larvae. 

Crane flies, like this female, often lose a leg when escaping predators

Named for their gangly legs, crane flies only live for 10 to 15 days as adults. The majority of their life is spent as larvae. 

Larvae are either aquatic or terrestrial depending on the species (there are 1,500 species in North America). Both feed on decaying plants, dead leaves, fungi and roots in moist habitats--such as on the bottom of a stream or pond, or in mud or wet moss near water. 

When full grown, the aquatic larvae will crawl from the water and burrow into the mud or soil. Terrestrial species stay where they are to pupate. The pupal stage is brief compared to the larval stage. 

Adult crane flies typically emerge in spring or fall during a period of 25-30 days. The synchronization of hatching results in swarms of males ‘dancing’ around for a female. The sole purpose of an adult crane fly is to mate to create the next generation.

Flight pattern is one of the two ways to tell an adult male from a female. Males fly erratically with undulations and spiral rotations. Females fly more steadily in a direct flight path.

The other way to tell males from females in the posterior (rear) end of their abdomen. The end of the abdominal segment on a male is rounded while the female has a tapered ovipositor (egg laying organ). The ovipositor looks like a stinger but the female doesn’t sting. Instead the female with stick the ovipositor into the soil or underwater to lay eggs. 

Upon close inspection of both males and females, you will notice a pair of stemmed knobs behind the wings. These drumsticks, called halteres, are a vestigial second pair of wings and are used for balance. 

Halteres are located just behind the first pair of wings

All flies in the order Diptera have halteres but they are particularly visible on crane flies. At the base of each haltere are sense organs that enable the fly to sense how fast it is flying, whether it is turning and whether it is being blown off course. 

Crane flies are not strong fliers and are easy targets for predators. Bats and birds are the main predators of crane flies and occasionally a crane fly can escape with only a missing leg or two. 

On the other hand, the less mobile larvae have numerous predators, including birds, fish, frogs, lizards, spiders, other insects and even skunks that dig them up. Crane fly larvae are also at odds with fisherman since they are used as bait. 

While it would be nice if crane flies did eat mosquitoes, they are still important to the ecosystem by breaking down organic matter and enriching the soil. 

Note: Published in the Bonners Ferry Herald on May 9, 2013. 

We’re not the only ones looking for shed antlers

As I walk through the woods, I spot one--not a spring wildflower, grizzly bear or ruby-crowned kinglet, but an antler. I feel like I won the lottery and in a way I have--nature’s lottery of being in the right place at the right time. 

Elk antler

With the number of elk, moose, white-tailed deer, mule deer and occasional caribou living here, one would think we would be tripping over antlers left and right. In addition, the skeletons of winter-kill, old age or a predator’s meal are far and few between.

We don’t find bones and antlers everywhere because they are a part of nature’s cycle. Finding one is excitement for us, but it means nutrition for animals.

Antlers are a valuable source of calcium, phosphorus, mineral salts and even protein. Imagine how much nutrition a mouse obtains from a 45 pound moose antler. 

For deer, elk and moose to grow antlers every year, they must obtain a significant amount of calcium from their vegetation-based diet. As the antlers grow, they draw from calcium reserves in the body that have been stored throughout the year.

Once shed, antlers provide valuable nutrition for mice, squirrels, porcupines and even coyotes, wolves and bears. 

With that many animals ready to gnaw on antlers, finding one without chew marks is quite a feat. Depending on where the antler was shed, a several-year-old antler may only have a few chew marks, be reduced to the main beam or be completely consumed.

An older white-tailed deer shed with only one spot chewed on

Amazingly, rodents can gnaw through antlers quite easily with their specialized teeth. Rodents, such as porcupines, squirrels, chipmunks and mice, grow strong, sharp front teeth. Only the front of the teeth are coated with a layer of hard enamel. So when the rodent gnaws on an antler, the back of the teeth wear away faster than the front resulting in chisel-shaped teeth. Thus, the rodent’s continuously growing teeth become sharper with use.

Wolves and coyotes, whose carnivorous teeth can easily break bones, will almost completely eat a moose antler. They particularly go after the softer portions of the moose antlers which are found in the center between the tines. All antlers develop an outer sheath of compact bone and a slightly spongier core.

As with mushrooms and cones, squirrels are known to haul off chunks of antlers and store them for later in holes in trees, under rocks or in their middens.

One of the most unlikely consumers of antlers are the elk and deer themselves. Olaus J. Murie describes in “Animal Tracks” of seeing reindeer in Alaska chewing on each others antlers while they were still attached. Elk herds in Wyoming also have been observed chewing on each others still-attached antlers. 

Since deer and elk don’t have teeth like rodents, they chew with their grinding (molariform) teeth. These teeth leave distinctive rough marks that look like the antler was gouged in a clumsy manner.

With antlers being chewed on while still attached and the number of animals that gnaw on shed antlers, it is truly amazing we find any antlers at all.

Note: Published in the Bonners Ferry Herald on May 2, 2013.