Midwest bird watching

Hole in an Owl's Tongue?

5/1/2020

All across the country students are getting ready for their final exams despite the lockdowns, so I think all of you should join in the merriment and feel the joy of taking a 2-part test.

Part 1: Open wide and say, "Ahhhhh!" Take a look at your tongue. Is it barbed and does it have a big hole in it? No? You're probably not an owl then. Good. You passed that part. Those that didn't pass get to eat a mouse.

Part 2: Why is there a hole in this owl's tongue? I'll give you a minute to come up with a creative answer using haiku or interpretive dance.

Answer to Part 2: The hole you see in the back of the tongue is called the glottis. It's the entrance to the windpipe (trachea). When the owl swallows, the glottis acts as a valve and closes so the food doesn't "go down the wrong pipe".

Some of you failed that exam, so I'll give you bonus points if you can identify the owl in the first photo. Hint: it starts with "Great".

Mutant? Or failure to launch?

4/25/2020

Even if you are self-quarantined due to COVID-19, there’s always something new and interesting to see in your own yard. Take a look at this lovely gentleman, for example. It doesn’t look like the stereotypical American Goldfinch, does it? We’re heading toward mating season for the goldfinch, so by now most of the males you see at your feeders have almost finished molting into their trademark golden and black plumage. However, some males won’t finish changing into their breeding plumage until June. This failure to launch doesn’t necessarily condemn this bird to a life of bachelorhood living in his parents’ basement. There’s still hope for him. Since goldfinches feed on thistles and similar seeds, they breed later than most of our songbirds, waiting for those seeds to be in abundance to feed to their young. So never fear! This late bloomer will probably do some “adulting” and find a lovely mate. Or at least his parents hope so! Ha!

Duck, Duck, Goose!

4/15/2020

Let's play the children's game of "Duck, duck, goose!"
If I ask people to tell me the color of a male Mallard's head, most would say it is green. That's true in bright sunlight, but if you're lucky to catch one on a bright but overcast day, you'll see a beautiful blue sheen mixed with the blue. The females are no less lovely, sporting an intricate brown and white pattern with just a hint of rust.
If I ask people to describe the nest of a Canada Goose, I would get a range of answers, and all of them would likely be correct. Take a look at these two nests. One is a master woodworker that painstakingly wove twigs together to form a basket that Longaberger would envy. The other is a master at remodeling, transforming a tree stump into a perfect nursery.

Baltimore Orioles

4/15/2020

There are few birds more beautiful in song and plumage than the Baltimore Oriole. The song is liquid and rich resembling the sound of a flute, and both the male and female have beautiful orange and yellow colors accented with black and punctuated with white. I've put out the welcome mat for my resident Baltimore Orioles. They should be returning any day now to build their nest that resembles a stocking hanging from the outer tip of a branch. If you want to attract orioles, don't bother with that orange syrup they sell at the stores. Instead, put out orange halves or plain grape jelly. Better yet, plant a mulberry tree so you and the orioles can share the fruit!

Mourning Warbler

7/18/2016

Discovered in 1810 by Alexander Wilson in Philadelphia, the Mourning Warbler migrates through Indiana in the spring on its way to its breeding grounds in Canada and northern portions of the U.S., and again in the fall on its way to the wintering grounds in the tropics. According to Audubon scientists, the Mourning Warbler breeding ground is expected to move much further north over the coming decades, as illustrated by Audubon's interactive model: http://www.audubon.org/field-guide/bird/mourning-warbler. The change will likely impact the timing of their migration and their appearance in Indiana.

With their subdued coloring, preference for thickets, and solitary nature, it can be difficult to spot a Mourning Warbler. Like most warblers, they have a habit of darting from branch to branch, particularly if you are trying to take a photo! Most Indiana birders struggle to find a Mourning Warbler out in the open, so imagine, if you will, seeing a variety of different warblers, including Mourning, all in a line, holding still, ready to be photographed! Gene Stratton-Porter had that experience and she shared it with us in "Homing with the Birds":

"In a line on a wire fence, there was a string the length of a city lot, of warblers gathering for migration, while over several bushes before and close behind the fence flocked dozens upon dozens more of these trim exquisite little birds. Of course, the predominant colour was yellow, there being the pure gold of the summer yellow bird and the slightly deeper shade of the prothonotary. There were the deep orange of the Blackburnian and the mottled yellow of the magnolian. There appeared prominently on the wire the yellow head and throat of the blue-wing, the stronger touch of yellow of the redstart, the black-throated green warbler, the yellow pine and the yellow-touched hood and mourning warblers. There were a number of specimens of the black-throated blue warbler and the still paler cerulean. There was at least one specimen of the bay-breasted warbler, with robin-breast colour on the top of its head and all over its underparts, and there were enough chattering, little warblers I could not identify to have made a large flock...As a rare and unusual sight I can think of no experience in field work to surpass the beauty of this picture."

Prairie Warbler

5/15/2016

Despite its name, Prairie Warblers are not typically found in prairies or in back yards. As an early successional species, they prefer large brushy areas and young trees. They are not widespread in Indiana, and even the earliest records of sightings are few. Prairie Warblers were first recorded in the northern half of Indiana in 1892, with one recorded in Wabash on May 2, 1892 and two in Lebanon on April 29, 1892. In that year, the Prairie Warbler had only been reported in four locations across Indiana. (Amos Butler, Proceedings of the Indiana Academy of Science, Volume 3, 1893).

This tail-wagging little bird has been featured on several postage stamps, including stamps in Grenada, Barbados, British Virgin Islands, and most recently in St. Kitts. In 1951 the National Wildlife Federation offered Peterson's illustration of a Prairie Warbler in the form of a collectible conservation stamp, and American Bird magazine offered slides of male, female and nestling Prairie Warblers for $0.50 in 1903. For the more gruesome, barbaric collector, you could buy a Prairie Warbler skin for the low price of just $0.15 in 1895. That was a bargain compared to the cost of a Bald Eagle at $6.00. (Natural Science News, Volume 1, October 5, 1985).

Thankfully we no longer shoot songbirds and sell the skins as collectibles. Nevertheless populations of many birds remain in decline largely due to human activity, loss of habitat, predation, and parasitism. The USGS North American BBS (Breeding Bird Survey) Population Trend Map for 1966-2013 shows an unmistakable decline in breeding Prairie Warblers in several states including Indiana. Between 1966 and 1993, the Midwest had an alarming 44% decline in breeding Prairie Warblers, and an overall 66% decline from 1966 to 2014. By the way, I confess I have a bit of an obsession with these BBS Trend Maps. I am in charge of the BBS for Adams County, and I assist with the BBS in Wabash and Huntington Counties, so I look at the Trend Maps often. Even if you are not helping with the BBS, I would encourage you to take a look at the Trend Maps for your favorite birds. You might be surprised. Incidentally, when the map indicates a percentage decline, that's not the total decline. It's a yearly decline. A "-1.5" indicates that the population dropped 1.5% each year from 1966 to 2013. Those declines add up!

Indiana University professor Val Nolan, Jr. studied the Prairie Warbler populations extensively and wrote a book in 1978 about his findings: "Ecology and Behavior of the Prairie Warbler". His findings were troubling. The nests he studied suffered 24% parasitism by cowbirds, only 69% of the warbler nestlings survived to adulthood, and the annual female mortality was 35%. Using those numbers, he calculated that the population would barely replace itself. The U.S. Forest Service has conducted a more recent study of the Prairie Warbler and found that the biggest cause of the decline is no longer the cowbird, but habitat loss. (Conservation Assessment for Prairie Warbler, U.S. Forest Service 2001).

Fortunately, several Prairie Warbler habitats are being preserved. I found the bird in this photo happily residing at the Indiana Dunes last spring. New Jersey has set up a 1200-acre preserve specifically for Prairie Warblers: the Michael Huber Prairie Warbler Preserve.

If you decide to go in search of a Prairie Warbler, and if you bird by ear, take note: Prairie Warblers have two distinct songs. One song is used for courtship while the second song is used to mark territory. An excellent video of a Prairie Warbler singing his heart out can be found here: https://www.youtube.com/watch?v=XLKLCqN8WS0

Albinism vs. Leucism vs. Dilution vs. Progressive Greying

3/6/2016

Is this hummingbird an albino? Or is it suffering from leucism? Or perhaps it is displaying signs of dilution? Or maybe it has a condition causing progressive greying? The answer might depend on whom you ask.

There has been some confusion and disagreement in the scientific community about the exact nature of each of these conditions. For example, is leucism caused by a lack of pigment? Or by a significant reduction in the amount of pigment deposited in the feathers? We aren’t completely certain. However, the basic cause and definition of each condition is generally agreed upon.

Albinism is caused by a genetic mutation that results in a complete absence of tyrosinase in pigment cells. Tyrosinase is an enzyme that is located in melanocytes. Melanocytes produce melanin, which is the substance that gives your skin, hair and eyes their color, and it gives color to a bird’s feathers. With no tyrosinase, no melanin is produced, so a bird’s feathers will appear white, and the eyes will appear pink. Albinism also affects the bird’s eyesight, causing the bird to have difficulty spotting predators and shortening its lifespan. Since albinism is an all-or-nothing condition, there is no such thing as “partially albino”.

Leucism is a reduction, rather than a complete lack, of pigment. Birds with leucism may have a few white feathers (partially leucistic), or be predominantly white, depending on the extent of the condition. Leucism is inherited, but it usually displays differently in the parents than in the offspring. A parent may have white feathers on the wings, while the offspring has white feathers on the tail, for example. It is an inherited trait, but it is recessive so it can skip generations.

Dilution is a condition that causes the feathers to appear more pale than normal. The bird may appear to have been sprayed with a fine mist of white paint and look washed out. In these birds, the melanin is present, but the cells are not producing as much pigment as normal birds.

Progressive greying or vitiligo results in white feathers, but the change occurs over time. The bird may have normal coloring when young, but the bird turns whiter as it ages. It is caused by the progressive loss of pigment cells with age.

So which condition does this hummingbird have? I’ll let you be the judge!

Pine Siskin

2/28/2016

This finch dressed like a sparrow can be seen in abundance one year, then rarely the next. The migration patterns are variable. During irruption years Pine Siskins travel further south and east in the winter in search of food. Normally seen in the northern states, some irruption years have resulted in large flocks of Siskins in places as far south as Louisiana, Alabama and Florida. In the winter of 2007-8 there were Pine Siskins reported at only 24% of the Project FeederWatch Sites. The following year was an irruption year, with 50% of the Project FeederWatch sites reporting flocks of Pine Siskins. Their movements are variable, with some migrating from northeast to northwest, while others migrate from north to south. A Siskin banded in Pennsylvania was later recaptured in Washington, while another bird banded in Texas was recaptured in Minnesota. They migrate in flocks of a half dozen to hundreds, often stopping at nyjer feeders along the way to dine alongside goldfinches.

They consume a variety of insect and weed pests, including aphids, scale insects, and thistle. As the flock forages through the trees, parts of the flock "leapfrog" over one another. "Often when feeding, there are no birds in flight; at other times part of the flock may take wing and pass over those still feeding to other food trees. As the birds thus go "leapfrogging", the entire mass of the flock of busy, lisping birds appears to flow through the forest. Then all of a sudden the lisping ceases and the flock is silent; it takes flight with a very audible whirring of wings and flies rapidly away" - A. C. Bent, "Life Histories of Familiar North American Birds".

The courtship is a sweet combination of a song and a dance on the wing. Louise de Kiriline Lawrence, naturalist and frequent contributor to National Audubon Society's magazine "Audubon", described the courtship beautifully: "With a beam of sunshine illuminating his golden flashes, the male rose into the air with tail spread wide and wings in a blur of rapid motion. To the accompaniment of a flight song which seemed to express far more musical adoration than could be contained in so small a body, he described circle after circle around his chosen mate. That the female reflected none of her partner's emotion in no way seemed to dampen his ardor and, after he dropped on to a twig from pure exhaustion to catch his breath, a few moments later he rose again in a repeat performance no less ecstatic than the first... In the midst of all this sweet singing, two birds swing into the air in an extensive 'cloud chase,' their movements tightly synchronized as they alternate in the roles of pursuer and pursued... The female sat on a twig. Presently the male alighted on the same twig, hopped up to her and offered her a small particle, of what I could not see. She crouched and, with trembling wings, accepted the offering."

Siskins are often thought to be rather tame. E. R. Davis studied the Siskins in 1926 and wrote: "In a short time the birds came to regard me as their friend, and in the days that followed grew to be exceedingly sociable and to lose every vestige of fear. Whenever I would appear at the window, or step outside the door, down they would come and, settling upon my head, shoulders, and arms, would peer anxiously about for the food that they had learned to know I held concealed from them in a box, dish, or other receptacle."

Pine Siskins may be tame, but they are also tough. They can withstand temperatures down to -94˚ (that's 94 degrees below zero!) by increasing their metabolic rate up to five times their normal rate for several hours! They also put on large fat deposits to help insulate themselves, and they store 10% of their body weight in seeds inside their crop to sustain them for up to 6 hours in subzero nighttime temperatures.

Dark-eyed Junco

2/16/2016

"A very quiet and well-conducted little member of our winter choir, with habits similar to those of the nuthatch, is the junco, with dark head and back, white breast, and grey sides. With an ivory-white bill, he feasts daintily at our winter offerings, occasionally remarking: 'tsip, tsip'. This is merely a whisper of sound. Occasionally he pauses and whispers a high, halting strain of a few notes with small variation that I am unable to give any form of syllabication." - Gene Stratton-Porter, "Homing with the Birds".

You have no doubt seen these cute little birds hopping on the ground underneath your bird feeder in the winter, but you aren't the only one watching them! Scientists have studied this species extensively. Over 1,300,000 Juncos have been banded since 1955, and over 15,000 of the banded birds have been recovered.

Researchers at Indiana University have conducted numerous studies on Juncos. They built the Kent Farm Bird Observatory facility including indoor and outdoor free-flight aviaries for housing flocks of juncos. A recent I.U. study monitored the effects of testosterone on Juncos. Increased testosterone allowed males to win mates, but they lost interest in raising their young had a shorter lifespan (Ketterson, et al., Indiana University 2007). In 1994, I.U. scientists studied the ability of Juncos to survive in winter when food is scarce by tracking the variations in their fat reserves. They noted that Juncos choose different wintering latitudes as they age (Rogers, et al., Indiana University 1994).

Scientists in other areas of the country have also be studying Juncos extensively. Their movements over (or more typically around) hills were tracked for three years in New Jersey. Not surprisingly, the birds chose the lower altitudes whenever possible (Schaeffer, "North American Bird Bander" 1979). The Junco's increased oxygen demands in winter are met by the bird's ability to increase its oxygen-carrying capacity (Swanson, Oregon State University 1990). Scientists have even studied the preening oils of Juncos and found that Juncos can distinguish between males and females by the odor of the oils, and they can use the odor to determine whether a bird is larger or smaller. Surprisingly, the females seemed to prefer the smaller males in this study (Whittaker, et al., "Behavioral Ecology" 2011).

Why are Juncos studied so often? They are easy to observe! They are common and sociable so it is not difficult to find a large group. They come easily to feeders so it is a simple task to attract them to net sites.
The interest in this bird and volume of study has even resulted in a popular documentary: "The Ordinary Extraordinary Junco" (http://juncoproject.org/). The film was designed by Indiana University to be a revolutionary type of multimedia textbook, teaching high school and college students in 8 "chapters" about the scientific method, ecology, genetics, physiology and animal behavior. I.U. allows free screenings of the 88-minute film for non-profit organizations and independent theaters upon request, so if you want to learn more about Juncos, you might want to arrange a screening for your local Audubon Society. As Bob Duquesne stated in his review of the film in "BDN Maine Outdoors" , "I will never look at a junco the same way again... [T]his little gray bird has a lot to teach us, about birds and about ourselves."