Millie and Roy, back again in 2014

To see a vortex of migrating cranes in western Nebraska, go to

Sandhill Crane Vortex from Christy Yuncker Happ on Vimeo.


Millie and Roy returned on May 4th and began incubation on May 12th, but the eggs did not hatch. They foraged and danced often during the summer (see video below) and then departed on migration on August 29th.

The Early Life of Pi

For the Early Life of Pi, go to Pi's homepage.

A pair of sandhill cranes, who we know as Millie and Roy, has nested on our property for over a decade. Christy Yuncker Happ has watched, kept a written journal, and photographed Millie, Roy, and their colts through every day of 10 nesting seasons. They hatched 11 colts and fledged 7.

In 2013, Millie and Roy returned from migration to a snowy pond on May 8^th. They began incubation on  May 18^th.

Pi hatched on June 16^th, fledged on August 8^th, and migrated with Millie and Roy on September 8^th.  Over 13 weeks, Millie and Roy coached Pi to dance, to run and wing-flap in pre-flight training,  and to learn the social cues for flying in tandem.

Pi's progress as he foraged and learned to dance and fly is described in 15 gallery-segments of stills and videos. To view the Table of Contents, click on the image below.

Is crane dance innate or learned?

Crane dance is iconic. All 15 species of crane communicate with elaborate body language¹. Comparisons among species reveals clear and consistent distinctions.

Do species differences in dance prove crane displays are innate?         We think the question is inappropriate and based on a false dichotomy.

Animal behavior was validated as "real science" when the 1973 Nobel prize in Physiology went to Karl von Frisch, Konrad Lorenz, and Nikolaas Tinbergen.

At the time of that 1973 prize, neurophysiology was limited to electrophysiology of individual nerve cells and included little more than hand-waving at the psychological realm that emphasized learning, emotion and mental processes. 

The research of these 1973 Nobelists was solidly grounded in precise observation of a defined set of behaviors, with a perspective that dodged between the sentimentality of anthromorphism and the formal dogmas of behaviorist psychology rampant in their day. The scientific rigor of these ethologists first bought a measure of scientific respect to biological study of behavior. To encourage a thorough examination of a behavior, Tinbergen² suggested that each behavior should be explained according to:

• Function (adaptation)
• Phylogeny (evolution)
• Causation (mechanism), and
• Development (ontogeny. 

None-the-less, ethology also had its own dogmas -  for example, that animal behavior is composed of "fixed action patterns" that are expressed when genetically-defined "sign stimuli" act on an "innate releasing mechanism". 

What physiological mechanisms underlie the fixed-action-pattern concepts? In his early writings, Lorenz attempted to explain behavior by analogy with a hydraulic model which is engagingly depicted in the animated gif borrowed from flyfishingdevon.co.uk.  Tinbergen used an electrical circuit model.

Neither analogy was readily transferable to flesh and blood.

The scientific approach to the songs of birds emerged at the same time as the birth of ethology, but "birdsong science" avoided tortured mechanistic analogies. Instead, research on birdsong focused on physiological linkages between behavior observations in the wild and experimental neuroscience in the laboratory.

Songs of nightingales, canaries, and other birds had delighted esthetes and challenged scientists since the Renaissance.

Birdsong research became tractable due largely to the use of the sound spectrograph, a device  invented in World War II for underwater eavesdropping on enemy submarines. In pioneering laboratory and field investigations, William Thorpe, Peter Marler and many others (see Nature's Music³) recorded and dissected the songs of birds and meticulously cataloged the species-specific differences.

Birders (and birds themselves) can readily identify each bird species by its unique song. Does it necessarily follow that bird songs are innate?

A pertinent response to this question is the "learning curve" as young male songbirds become able to sing like their fathers.  As Marler notes, one conclusion is inescapable from the research results:

"when we adopt a developmental approach, which is what Tinbergen was advocating, the instinctive/learned distinction loses its logical underpinnings."²

Since the mid-20^th century, there has been a torrent of scientific papers on the progressive changes as young birds acquire adult song and on the roles of the various brain centers that preside over singing.

"Practice makes perfect."

Birdsong vocal learning is now an attractive general model for research on the cellular basis of motor learning. One example of motor learning is a high school athlete becoming proficient at pitching a curve ball. The rough draft of the "throwing" behavior is already present in our brain and is perhaps innate.  But training and practice profoundly refines that rough draft.

For songbirds, young males acquire their song "target image" by listening to a model tutor, usually their father. Then, weeks later, the young birds begin to sing an adult tune on their own as they acquire an ability to duplicate the memorized song of the tutor. As they practice, birds embellish and perfect an innate capacity.

The brain centers and nerve networks

In the last few decades, laboratory scientists have identified the brain centers and networks responsible for birdsong and vocal learning.

The neurocircuit diagram (right), adapted from one published by Michael Brainard's lab at the University of California-San Francisco, offers a reconstructed layout of birdsong pathways⁵ in the brain. The centers are:

1. posterior centers (HVC, RA...) that drive motor neurons of the syrinx [shown in black],
2. anterior centers (Area X, LMAN....) required for song learning [shown in gray & red],
3. centers that motivate a bird to sing [circled in pink], and
4. sensory centers [not shown] that monitor each song emitted and thus allow comparisons of output with other songs held in memory.

Now in the 21^st century, research of many labs is directed toward exposing the physiological and molecular bases for song variability and individual specificity. Birdsong has become an important biomedical model for probing the cellular bases of learning. We will discuss the centers in more detial in future Blogposts.

As birdsong science took off, the underlying neuroscience of bird brains experienced a revival due to results from molecular embryology. The neuro-geographical map of bird brains was re-interpreted and revolutionized in the last decade (Reiner et al., 2004⁶ and Jarvis et al., 2005⁷  and discussed in our earlier Blogpost).

Birdsong and crane dance

Walking, flight, and birdsong improve with practice, as does the acquisition of dance skills by young Sandhill Cranes (known as colts). Very young crane colts display to each other and interact with their parents, starting in the first few days after hatching.  Over the ensuing weeks, the parents "encourage" the colts to dance, as shown in the image below when the colt was 21 days old.

In the weeks following, the  colt flail-dances with the father parent at 35 days of age (below left below) and dances smoothly with parents by 40 days later (below right).

Sandhill crane displays are complex. Some of the dance lexicon is depicted in print¹ and on the web and progressive acquisition of dance skills is generally summarized on a related page.

The table outlines intriguing behavioral parallels between the acquisition of adult song in young male zebra finches and acquisition of dance displays in young cranes.

For finches, the neuroscience/brain center correlates of the behavior are under intensive study in several major research laboratories. There is yet no data on the brain centers that preside over dance in cranes.  However, the acquisition of crane dance behavior is strongly suggestive of motor learning and that is underlain by brain circuits like those for birdsong.

Crane dances are refined over many years. Dance performance probably improves over the 2-3 years while young cranes dance in crowds to assess potential mates. Furthermore, we have a photographic chronicle that demonstrates marked shifts in the selection of postures and the execution of displays for the dances between the male and the female of a pair that we have watched on their nest territory for over a decade.

As Peter Marler noted (quoted above), the instinctive/learned dichotomy for birdsong disappeared when scientists in the 1970's used a developmental approach. Our developmental approach to crane dance appears to yields the same conclusion: dance is not wholly innate or wholly learned.

Dance reflects motor learning as the bird refines and develops genetically based capabilities. For dancing of cranes as for vocal learning of songbirds, motor learning optimizes better communication among members of a species.

Birdsong and vocal learning are generally thought to have evolved independently in three avian lineages: oscines (higher passerines), hummingbirds, and parrots. In an important study, Erich Jarvis' lab at Duke University and his German colleagues have shown that brain centers for birdsong are akin to brain motor centers, like those concerned with walking and flying.⁸ The ontogeny of dance in cranes may well reflect the presence of motor learning in a fourth avian lineage.

Finches progressively refine and improve their songs by comparing with a memory of their tutor's song which they heard during a sensitive period in their young lives. Whether cranes use memories of their parents or the responses of dance partners (or both) remains to be investigated.  It may be that crane motor learning is lifelong, unlike songbird vocal learning where sensitivity to the tutor is restricted to a particular period in a young bird's life.


References-
1. DH Ellis, SR Swengel, GE Archibald & CB Kepler, 1988. A sociogram for cranes of the world. Behavioral Processes 43:125-151
2. N Tinbergen, 1963. On aims and methods in ethology Zeitschrift fur Tierpsychologie 20:410-433.
3. P Marler & H Slabberkoorn, 2004. Nature's Music - The Science of Birdsong  Elsevier 
4. P Marler, 2004.  Chapter 1: Science and birdsong: the good old days, pp 1-38 in Nature's Music.
5. TL Warren, EC Turner, JD Chaerlesworth & MS Brainard, 2011. Mechanisms and time course of vocal learning and consolidation in the adult songbird. J Neurophysiol 106: 1806-1821.
6. ED Jarvis, O Güntürkün, (25 other authors) A Reiner & AB Butler, 2005. Avian brains and a new understanding of vertebrate brain evolution. Nature Neuroscience 6:151-159.
7. A Reiner A, (27 colleagues), Jarvis ED, 2004. Revised nomenclature for avian telencephalon and some related brainstem nuclei. J Comp Neurol 473:377-414.
8. G Feenders, M Liedvogel, M Rivas, M Zapka, H Horita, E Hara, K Wada, H Mouritsen & ED Jarvis, 2008. Molecular mapping of movement-associated areas in the avian brain: a motor theory for vocal learning origin. PLoS ONE 3: e1768, DOI 10.1371/journal.pone.0001768

Best books - Sandhill Cranes in the Great Plains and elsewhere

BOOK REVIEW:  
Sandhill and Whooping Cranes: Ancient Voices over America's Wetlands by Paul A. Johnsgard. Bison Books of the University of Nebraska Press [published 2011] and

On Ancient Wings: the Sandhill Cranes of North America by Michael Forsberg [published 2004]

The spring staging of Sandhill Cranes in the shallows of the Platte River in Nebraska ranks among the great mass migratory events on the globe.

Paul Johnsgard provides an overview of the status for Sandhill and Whooping Cranes that updates his classic Crane Music [1991].
The prose is consistently graceful and the illustrations both meticulously accurate and artistically delightful. The first three chapters of this book are status reports on "Lesser Sandhills", "The Other Sandhills", and "Whooping Cranes". Each blends history and biology, spiced with personal observations. Paul imbues the descriptions with awe and respect for these magnificent birds.

Lesser Sandhill Cranes endured the depredations of 19th century market and sport hunting and now the Platte collects 400,000 to 500,000 birds every March. Nonetheless, these cranes are still under some threat, from hunting pressure during the winter in Texas, from atrophy of the Platte due to agricultural irrigation, and from competition for food from thousands of resident Canada Geese and millions of migratory Snow Geese that arrive in Nebraska a few weeks earlier.

The mid-continent crane populations have a hourglass-shaped migration pattern. In late February and March, they converge on the Platte from wintering sites spread from western New Mexico and northern Mexico to the Gulf Coast of Texas. Once in the spring fueling mode in Nebraska, the cranes spend weeks of day-times converting waste corn from the surrounding fields into fat to store for the second major leg of their migration. Every night, they return to dodge the powerlines and touch down in cacophonous cascades until they can roost, huddled in swirling transient clusters in the shallows of the river.

On a warm March day with rising thermals, groups of birds spiral gently upward and splay out to the north, finally ending their journeys at higher latitudes from Hudson Bay to Siberia.  As they near their traditional nesting territories, ponds and marshes are still icy. Within 3-4 months, the crane colts are fledged and as temperatures dip below freezing again and families start a long more leisurely journey south.

The Other Sandhills are a collection of populations or races that are rather like clans of nomadic people.  The birds differ somewhat in size (weight, wing-spread, bill-length, etc.) but are mostly distinguished by migration geography.  Some (technically Lessers) migrate from nesting grounds in southwest Alaska to California, others (technically Greaters) from Idaho to New Mexico or (the Great Lakes population) from Michigan to Florida.  These migratory patterns probably reflect the distinct cultures of each population that are passed year-by-year from experienced birds to younger ones as they travel together.

Some Other Sandhill populations (subspecies?) are non-migratory. The resident cranes in Florida grasslands, suburbs, and shopping centers overlap with migrants from Michigan in winter months. The more remote groups in Mississippi and Cuba remain threatened and isolated. A tiny population of these long-lived birds has persisted for many decades on a National Wildlife Refuge in Mississippi, often with yearly infusions of new colts hatched in captivity.

The stature and majesty of Whooping Cranes and their plumage captivates almost everyone who sees them. During the early years of the 20^th century, pressure from the millinery markets of sophisticates decimated their populations. In 1937, the establishment of the Port Aransas National Wildlife Refuge on the Gulf coast of Texas preserved a dedicated wintering ground, albeit precariously close to heavy commercial barge traffic on an intercoastal waterway.  Occasional illegal harvesting persisted, but somehow numbers held steady at a few dozen adults until the remote nesting ground for the Port Aransas flock was discovered in Canada twenty years later. Conservation efforts in Texas and Alberta and appeals to reduce hunting have paid off such that 263 cranes started from Texas on their journey toward Canada in 2010, along the path depicted in Johnsgard's map to the left. Continued vigilance and monitoring of the individual birds each year must remain a high priority.

Many well-publicized efforts have been devoted to establishing other Whooping Crane populations.  These include a failed attempt to cross-foster Whoopers with Sandhill parents in Idaho that started well but faltered, and a multi-year struggle, that was ultimately abandoned, to create a resident population in Florida.  As of 2009, the 22 surviving Whooping Cranes from this flock are being protected and monitored.

Still ongoing is Operation Migration, an entrancing project of a non-profit corporation working with the International Crane Foundation and the USGS in Patuxent (MD). Operation Migration nurtures hatchlings chicks at the ICF in Wisconsin and then teaches the young colts to migrate in the fall by following an ultralight airplane to Florida and returning in the spring, led by the ultralight back to Wisconsin. This flashy project seems to be working as some of the the returning Whooping Cranes are making nests in Wisconsin. The next critical landmarks are sustained nesting in the wild, fledging of significant numbers of colts, and independent migration (without an ultralight leader) to Florida.

Very recently, there is a new attempt to establish another resident population, this time in Louisiana. It will be many decades before we will know if any of these investments yield self-sustaining populations.

Like Sandhills, Texas Whooping Cranes migrate through Kansas, Nebraska, and the Dakotas, but they travel in small groups in the late spring.  Cranes are particularly vulnerable during these long migrations. The impacts of changing fashions in agricultural economics, pressure for increased biofuel production, and drought cycles which may be exacerbated by global climate change, are some of the factors that menace crane stopover sites, of which the most important is the Platte River valley.

The Appendix of Johnsgard's s slim, information-packed volume tells the reader exactly when and where to find cranes in 34 states and provinces of the US and Canada. It is very helpful to have one list of these unheralded habitats where cranes can be observed by carefully scheduling a visit.

Mike Forsberg may be best-known for his stunning images of fauna, flora, and scenery of the Great Plains. He is a keen observer and careful student of natural history, an avid conservationist, and a lucid writer. On Ancient Wings grew from several years of watching and photographing different populations of cranes.

On Ancient Wings is a series of vignettes of cranes in the wild, as Mike traveled from Alaska to Mexico, across to Florida and down to Cuba.

The informative text is enhanced by Mike's striking photographs of the cranes, their behavior, the neighboring animals and plants, and the landscapes. The images almost overpower the narrative that likewise deserves very careful study.  Mike introduces the reader to the local culture and the people who study and protect the cranes. Each crane population is unique and Mike's journal entries provide great local flavor.

Although Mike Forsberg started as a still photographer, more recently he has become skilled with video as well. His talent was showcased a few years ago in a NET (Nebraska Educational Television) video production for On Ancient Wings. 

For a lyrical introduction to Mike's skills, view the recent Flash video promoting his upcoming NET production on the Great Plains - America's lingering wild  or visit his exhibition in April 2011 at the National Museum of Wildlife Art in Great Falls, Montana.

Great Plains promo - NET Nebraska and Michael Forsberg from Michael FORSBERG on Vimeo.

Johnsgard's Sandhill and Whooping Cranes and Forsberg's On Ancient Wings very nicely complement one another. Both have a mix of the big picture and specificity, and each offers an informed original perspective on cranes and their biologies. Royalties from these books go to the Rowe Audubon Sanctuary, a craniac's mecca a few miles east of Kearney, Nebraska.

Cranes may sniff aphrodisiacs

 Do cranes emit and perceive sex pheromones?

Personal perspective

In 1958, one of the Blogauthors (George) chose Cornell University for graduate study in bird behavior and animal communication. I was intrigued by three kinds of signals:

• Sounds - Birds and insects have rich repertoires of chirps, songs, and buzzes.
• Visual displays  - Birds present feathery dynamic postures and insects flash markings on their wings.
• Scents  - In 1958, clever chemists used new technologies like gas chromatography to isolate pheromones¹ and defensive secretions² . Scientists were astonished to discover that a single substance could trigger a whole chain of behaviors in insects. 

Chemical signaling was the emerging field, but searching for avian pheromones appeared to hold little promise.  Pierre Grassé's Traité de Zoologie³, the zoologist's Bible of that era, stated that most birds are anosmic, without a robust sense of smell.

Thus I opted to do my doctoral thesis on insects when I changed advisers in 1959. 

What a difference a half-century makes! 

           ============================

What data argue that birds use pheromones?

In 1959, we knew:

1. Birds have well-developed exocrine glands, including uropygial glands at the base of the tail, anal glands, salt glands, and ear glands, most of which produce greasy odorous mixtures. 

2. Birds spread these secretions upon their feathers when they preen.

In 2010, we also know:

 3. Exocrine secretions, especially those from the uropygial glands, vary according to age, species, season of the year, and hormonal state^4-10.

 4. Birds are far from anosmic. Bird brains "have the right stuff" to distinguish odors.

• Birds have nostrils, olfactory cavities, and olfactory neurons that are anatomically like those of mammals. Olfactory information flows to well-developed brain centers that include the piriform cortex, amygdala, and entorhinal cortex^32,33, parts of the brain that are associated with emotion. As theropod dinosaur descendants gave rise to birds (see How birds think blog, 9-Feb-2011), the olfactory bulb became larger³¹, suggesting  increasing importance of the sense of smell to the life styles of birds. 
• Olfactory receptor (OR) genes encode proteins that are embedded in the surfaces of olfactory neurons and can discriminate among odorous molecules. Silke Steiger in Starnberg Germany^10-12 showed that birds have hundreds of OR genes, comparable in diversity to mammal ORs.  The fact that one large gene clade, termed γ-c, is expanded across the class Aves, argues for the importance of olfaction for many birds.
• In the last decade, there has been wholesale rethinking about bird brain architecture¹³. The superficial appearance of the brain differs between birds and mammals, but the contrasts are mostly due to topological shuffling of neuron clusters and centers. Birds have sophisticated information processing capacity. 

5.  Birds use their sense of smell, for example: to find food, to distinguish individuals from one another, to recognize nest sites (petrels), and for many other purposes⁵. Three notable examples involve mating.

• Since 1979, Jacques Balthazart and others at the University of Leige in Belgium have been convincingly pleading the case for duck sex pheromones from the uropygial glands, starting with their classic paper demonstrating hormonal control of secretion¹⁴. 
• Male chickens (roosters) court with a sequence of behaviors: first waltzing, then mounting, and finally copulating. Hirao and colleagues (2009) surgically excised uropygial glands of female chickens and then placed roosters with either intact or "glandectomized" females. Roosters waltzed equally with both groups of hens, but they mounted and copulated significantly more often with intact hens.  Surgically anosmic roosters couldn't tell the difference¹⁵.
• Tobias Krause and his colleagues at Bielefeld University in Germany recently reported that a songbird can recognize kin by smell. The experimental data clearly demonstrate that zebra finch chicks fostered at 2 days of age into unrelated broods prefer the odor of their hatch-nest over that of the foster-nest³⁴. 

6.  In 2010, the molecular components of sex-specific odorants were identified in the oils from uropygial glands.

• Jerome Mardon and colleagues showed that, during the breeding season, there is a sex-biased chemosignal (more C23-C28 esters) in uropygial secretions of female petrels. It has not yet been possible to demonstrate that the "Sex signal" affected male behavior under field conditions¹⁶.
• Jian-Xu Zhang and others from the Chinese Academy of Sciences (Beijing) report that a blend of 18-, 19-, and 20-carbon alcohols, found in uropygial secretions of both male and female budgerigars, are strongly enriched in males.  With a classic Y-maze bioassay, they showed that the alkanol blend, reconstituted from pure chemicals, was attractive to female budgerigars¹⁷. 

7. Recent papers document individual recognition by scent in humboldt penguins³⁵ , petrels³⁶ and zebra finches³⁷ .

8.  A 2013 paper³⁸ strongly suggests that male satin bowerbirds paint their spectacular bowers with chemical signals.  The paint is attractive females who taste it.

Why haven't more ornithologists seen birds use pheromones? 

Birders have logged millions of hours watching birds. How could pheromones escaped their attention for so long?

We think that the answer is threefold:

  = First, because birds don't wave mobile pendulous snouts as they walk about.

In a seminal article, Samuel Caro and Jacques Balthazart argue persuasively for the existence of bird pheromones. These authors suggest that birds aren't obvious when they use chemical signals:

 "Mammals extend their neck, move their head, sniff, and track the source of the odor.....Birds, in contrast, have developed a wide array of alternative communication signals and do not show behaviors typically associated with olfactory sampling..." ⁵ (italics added).

  = Second, because most of the accumulating evidence¹has been published in biochemical publications rather than the birder journals that are read by most ornithologists.

   = Third, because it takes a lot of expensive scientific slogging to get from observation and experiment in the field and laboratory, to purification of the molecules, to behavioral assay, and finally to manipulating physiological context, all of which must come together to definitively prove pheromone function.

The roles of pheromones can be obvious or subtle.

• Pheromones (including blends of several substances) can be classical releasers that trigger a quick behavioral response or primers that cause a specific but sustained change in physiological state. 
• Pheromones could mediate general arousal, like a perfume that is "chemical mood music".  
• A given pheromone signal could be emitted by both sexes and/or could impact both sexes. 

Pheromone research starts with observations of behavior. Let me digress by presenting a personal example:

In 1969 after several years of behavioral experiments, George and his students concluded that mealworm beetles use multiple sex pheromones^{18, 19} (diagram left): A) an attractant produced by male beetles for females; B) a substance from females that excites males; C) an antiaphrodisiac produced by males that inhibits other male competitors, and  D) primer pheromones that accelerate oocyte maturation in females.

Next, the behavior needed validation by chemistry. But my laboratory and other colleagues failed in attempts to chemically purify even one of these four putative pheromones. So instead, after 1970, we pursued research themes in cell and developmental biology.

In ensuing last 40 years, our conclusions, based on behavior, have been validated by the work of chemists. In 1986, a Japanese group identified B, the female beetle's attractant²⁰. Recently (2005), an English group isolated A, the male's attractant²¹. Since the existence of antiaphrodisiac C and primer D have not been definitively confirmed by isolation and bioassay of a pure substance, the case for each of these is yet incomplete.

 

The case for pheromones in Sandhill Cranes

Three lines of evidence strongly suggest that cranes use pheromones:

   =First - Cranes have capacious uropygial glands that secrete a melange of oils and waxes. The drawing to the right is the uropygial gland of a Sandhill Crane²².  In his classic inventory of uropygial secretions^23,24, Jürgen Jacob found that crane uropygial secretions contain unusually large proportions of sesquiterpenes and diterpenes, substances built up from isoprene building blocks like those used to make steroids. Isoprenoids are auspicious pheromone candidates.

   =Second - Every crane repeatedly harvests secretions of its uropygial gland (left, below) and wipes the greasy gue over their wing and body feathers (right, below) as it preens.

   =Third - In nature, both crane sexes exhibit a fascinating exploratory behavior (photo to the right) as they pace forward just before copulation. It has been sketched for Eurasian Cranes by Paul Johnsgard²⁵ (who called it 'parade march'). It has been named 'bill-raising' in Red-crowned Cranes by Masatomi and Kitagawa²⁶, and included in most accounts of crane precopulatory rituals^25-28.

In our Crane Display Dictionary²⁹, we suggest that the 'Parade-march' can facilitate olfaction.

We agree with Caro and Balthazart that most species of birds "... do not show behaviors typically associated with olfactory sampling".⁵ However, there are exceptions where sniffing seems evident. We believe that two of the notable  exceptions are the Parade-march posture of cranes and the Ruff-Sniff behavior of Crested Auklets (seen to the right in a drawing from Hunter and Jones).³⁰

Given these lines of evidence, we conclude that it is quite plausible that cranes emit and perceive reproductive pheromones. This idea deserves serious further investigation:

• Uropygial glands of captive cranes could be milked and analyzed. Are the secretions sex specific? age specific? seasonally changing? species specific? affected by changes in hormones? 
• A quantitative bioassay needs to be developed for cranes. With a behavioral or physiological bioassay, one could ask whether responsiveness to crude uropygial secretions, purified components, or defined mixtures varies with sex, season, endocrine background, etc.
• Can purified pheromones or mixtures be tools for improved crane husbandry and thus assist in conservation of endangered species of cranes?  

References:

1. Karlson P. Lusher M 1959. 'Pheromones': A new class of biologically active substances. Nature 183:55-56.

2. Roth LM, Eisner T 1962. Chemical defenses of arthropods. Ann Rev Ent 7:107-136.

3. Grassé P-P 1950. Traité de Zoologie, Tome XV. Oiseaux.

4. Hagelin JC, Jones IL 2007. Bird odors and other chemical substances: a defense mechanism or overlooked mode of intraspecific communication? Auk 125:741-761.

5. Caro SP, Balthazart J 2010. Pheromones in birds: myth or reality? J Comp Physiol A 196:751-66.

6. Kolattukudy PE, Rogers L 1987. Biosynthesis of 3-hydroxy fatty acids, the pheromone component of female mallard ducts, by cell-free preparations from the uropygial gland. Archiv Biochem Biophys 252:121-129.

7. Bhatttacharyya SP, Chowdhury M 1987. The effect of androgen on the composition of lipid material of the preen gland of pigeons. Folia Biologica 26: 15-32.

8. Bohnet SI, Rogers G, Sasaki G, Kolattukudy PE, 1991. Estradiol induces proliferation of peroxisome-like microbodies and the production of 3-hydroxy fatty acid diesters, the female pheromones, in the urogygial glands of male and female mallards. J Biol Chem 266:9795-9804.

9. Bhatttacharyya SP, Chowdhury M 1995. Seasonal variation in the secretory lipids of the uropygial gland of a subtropical wild passerine bird, Pycnonotus cafer, in relation to the testicular cycle. Biol Rhythm Res 26:79-87.

10. Steiger SS, Fidler AE, Valcu M, Kempenaers B 2008. Avian olfactory receptor gene repertoires: evidence for a well-developed sense of smell in birds? Proc Roy Soc B 275:2309-2317.

11. Steiger SS, Kuryshev VY, Stensmyr MC, Kempenaers B, Mueller JC 2009. A comparison of reptilian and avain olfactory gene repertoires: Species-specific expansion of group γ genes in birds. BMC Genomics 10:446-456.

12 Steiger SS, Fidler AE, Mueller JC, Kempenaers B 2010. Evidence for adaptive radiation of olfactory receptor genes in 9 bird species. J Heredity 101:325-333. 

13. Jarvis ED, Gunturkun O (25 colleagues), Reiner A, Butler AB, 2005. Avian brains and a new understanding of vertebrate brain evolution. Nature Reviews Neuroscience 6:151-159.

14. Balthazart, J, Schoffeniels E 1979. Pheromones are involved in the control of sexual behaviour in birds. Naturwiss 66:55-56.

15. Hirao A, Aoyama M, Sugita S 2009. The role of uropygial gland on sexual behavior in domestic chicken Gallus gallus domesticus. Behav Process 80:115-120. 
16. Mardon J, Saunders SM, Anderson SM, Chouchoux C, Bonadonna F 2010. Species, gender, and identity: Cracking the petrel's sociochemical code. Chem Senses 35:309-321.
17. Zhang J-X, Wei W, Zhang J-H, Yang, W-H. 2010. Uropygial gland-secreted alcohols contribute to olfactory sex signals in budgerigars. Chem Senses 35:375-382.
18. Happ GM 1969. Multiple sex pheromones of the mealworm beetle, Tenebrio molitor L. Nature 222:180-181.

19. Happ GM, Schroeder ME, Wang JCH 1970. Effects of male and female scent on reproductive maturation in young female Tenebrio molitor. J. Insect Physiol 16: 1543-1548.

20. Tanaka Y, Osawa K, Honda H, Yamamoro I 1986. A sex attractant of the yellow mealworm beetle, Tenebrio molitor, and its role in mating behaviour. J Pest. Sci 11:49-55.

21. Bryning GP, Chambers J, Wakefield ME 2005. Identification of a sex attractant from male yellow mealworm beetles, Tenebrio molitor. J Chem Ecol. 31: 2721-2730.

22. Johnston DW 1988. A morphological atlas of the uropygial gland.  Bulletin of the British Museum (Natural History). Zoology series. 54(55):199-258.
23. Jacob J, Plawer J, Rosenfeldt P 1979. Gefiederwachskompositionen von Kranichen und Rallen. Beitrag zur Systematik der Gruiformes. J Ornithol 120:54-63.

24. Jacob, J. 1982. Uropygial gland secretions and feather waxes. Avian Biology, Vol VI, edited by Farner DS, King JR, Parkes KC , Academic Press, New York, pp199-324.

25.Johnsgard P 1983. Cranes of the World. 2. Individualistic and social behavior. Papers in Biological Sciences, University of Nebraska, Lincoln, pp. 11-24.

26. Masatomi H, Kitagawa T 1975. Bionomics and sociology of the Japanese Crane, Grus japoniensis, II. Ethogram. Jour. Fac. Sci. Hokkaido Univ. Ser. VI, Zool. 19:834-878. 
27. Ellis DH, Swengel SR, Archibald GE, Kepler CB 1998. A sociogram for cranes of the world. Behav Process 43:125-151. 

28. Masatomi H 1983. Some observations on mating behaviour of several cranes in captivity. J. Ethol. 1:62-69.
29. Happ, CY,  Happ GM 2011. Sandhill Crane Display Dictionary. What cranes say with their body language. Waterford Press.
30. Hunter FM. Jones IL 1999. The frequency and function of aquatic courtship and copulation in least, crested, whiskered, and parakeet auklets. The Condor 101:518-528. 
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Updated: April 17, 2011 & January 5, 2012 & April 17, 2013

Twin colts hatched in 2010

Roy and Millie returned to their Goldstream Valley cranberry bog and its snow-covered frozen pond on April 22 -- Earth Day. The pair soon began exploratory nest building (left) and then started serious incubation as the snow fell lightly on May 4 (photo right).

We have seen cranes on this pond for 15 years. 2010 is the 10^th year that we know a pair of cranes has nested here. Photographs confirm that Roy and Millie have been the individuals nesting here since 2004. We suspect they have been summer residents here since the late 1990's.



The first crane colt (Lucky) hatched on June 4, 2010 and a second (Chance) on the next day. They spent the first two days near the nest, being fed insects by their parents and otherwise sheltering under Millie's wings.  

Crane brains and behavior 3 - Mental maps of local ecology in a Parahippocampal Place Area (PPA)?

For the past 18 days, our Sandhill Crane pair, Millie and Roy, have been trading incubation duties every 6-8 hours.  The off-duty crane feeds, loafs, calls, and inspects the neighborhood, including the nest-site pond and bogs across Goldstream Valley.

We believe that inspection allows cranes to monitor their environments. Inspection provides frequent updates to the mental map of the crane's world and also detects novelty (which might signal danger). In our previous Blogpost, we introduced the idea of such a map and drew parallels with spatial information that some bird species use to find food items that they have hidden previously.

Within the brain of a crane, where is the map of the neighborhood?  How is the information stored?