Summer School for Sandhill Crane Colts

For 13 weeks, parent cranes teach survival skills as toddling chicks metamorphose into athletic flying machines. For the "academic plan", see Core Curriculum and Colt Kindergarten. The week-by-week activities culminate in migration.

The core skills (school subjects) are: 1) Foraging, 2) Caution, 3) Dance/Display, and 4) Flying. The parents utilize vocalizations, body language, and rewards (food and dancing) in their three pedagogical tactics:

    • everyday examples and demonstrations,
    • excursions and field trips, and
    • coaching.
  • Weeks 1 & 2      
    Forage, observe,
    & sleep in tent
  • Weeks 3 & 4     
    Forage,
    walkabouts,
    & first dances
  • Weeks 5 & 6  
    Family dances &
    colts run/flap
  • Weeks 7 & 8
    Adult flight
    demos, flee
    & hide
  • Weeks 9 & 10
    Preflight
    coaching,
    first colt flights
  • Weeks 11-13
    More flight
    practice,
    & excursions

Weeks 1 & 2 [~June 4-17]

  • Foraging - After the first colt hatches, one adult continues to incubate while the other stays near the nest (within a few meters) catching insects to feed the colt. Photo right shows Jacques-09 being fed by Millie.
  • If there is a second colt that hatches on the next day, then parents and colts forage within 50 meters of nest.
  • Caution - Colts rest by tenting under the wings of an adult, most often their mother but sometimes their father. Oblio-08 is shown tenting to the left.
  • Foraging - The family forages farther from the nestsite on the third day. Adults walk quite deliberately about the nest territory (~250 meters across). Colts follow closely and swim across short stretches of water. Both colts may be associated with one parent or one colt can follow each parent. In several years, the larger colt (hatched first) followed within a meter of the parent while the smaller colt often lagged 10 meters behind.
    In week 2, the family forages further, including half-day or full-day walkabouts around the neighborhood surrounding the nest territory.
    Colts are avid observers. The photo to the right shows Lucky-10 and Chance-10 as they study Millie. When the adults do wing stretches, colts watch and imitate.
  • Foraging - Parents offer colts insects (small dipterans, beetles, adult dragonflies, crane-fly larvae), voles that they catch and dismember, cranberries, tubers, and grain. By the end of the week 2, colts peck at berries, grain, and leaves and may be feeding themselves, but the bulk of their food is provided by parents.
  • Adult behavior - Unison calling by parents is often answered by cranes 1-5 km away.
  • Caution - In their first weeks, colts are especially vulnerable. The parents are particularly wary when ravens, northern harriers, or mew gulls are nearby. Whenever a predator is detected, colts crouch down in the grass, often under their mother. If the predator approaches, the parents defend vigorously, as seen in the left photograph which shows Millie shielding the colts (Jacques-09 and Phyl-09) and Roy Bill-stabbing at a mew gull. The mew gulls had nested within 30 meters of the crane nest. By midsummer, their gull chicks had become colt food and the adult gulls deserted the pond.
  • Dance-Display - We have seen 4-day old colts hold out their wing-stumps and face off to one another. In the first week, colts appear to signal hunger by pecking vigorously at one another. In the second week, the behaviors continue - they face off , peck and/or chase each other, but the competition is not vicious. Photo right shows Lucky-10 and Chance-10 at 12 days.
  • Fratricide is not usually responsible for colt death - On webpages and in the published literature, it is repeatedly stated that the stronger crane colt kills the weaker one and thus two hatchlings yield one fledgling. We think that this is an error of interpretation, perpetuated by frequent repetition. It does not fit our observations. Bill-sparring between sibling colts is quite common, and certainly most crane pairs fledge only one of their hatchlings. However, over our years of observation, we have never seen the stonger colt (usually the first-hatched) injure the weaker one.

    The stronger colt runs faster, sticks closer to the foraging parents, and gets more food. The weaker colt lags behind its foraging parents and so gets less. Attentive parents like Roy and Millie take food back to the cheeping follower, but the laggard always gets less.

    The weaker colt usually dies overnight. In our experience, the parents and sibling seem distressed by the demise of the weaker sibling, most dramatically reflected in the behaviors that followed the death of Phyl-09 at three weeks. For further discussion, please see hyperlink blog on death of a colt and the complementary photo gallery .

=========
Based on our seven seasons of observations, we believe that the calendar dates shown are typical for cranes in Fairbanks.
Adults usually return from migration in the last week of April, begin incubation between May 3 and May 6, and colts hatch 31 days later. The cranes depart on their southward migration in the first few days of September.

Weeks 3 & 4 [~June 18-July 1]

  • Foraging - As parents pace slowly and forage, the colts (Peter Pan-04 at 3 weeks in the left image) run after them waving their wings. They often cross water channels which the colts must swim. By week 4 (right above) , colts show pinfeathers.
  • Foraging - Adults forage for insects, voles, ducklings (Roy appears to be offering a strip of fresh duckling to Lucky-10 at the right), berries, or grain. Adults "butcher" the duckling by vigorously shaking its carcass back and forth and bits of meat are then fed to the colt. In the 4th week, colts feed independently on berries and grain and appear to look for insects in the grass.
  • Caution - Colts continue to tent-sleep under the wings of the female crouched on the ground. The male generally stands closeby on one leg, sleeping but opening an eye from time to time.
  • Dance/Display - Late in the fourth week, the adults do short dances most evenings after feeding, and sometimes the colts flap their wings as well. Colts may even initiate dances, as did Lucky-10 in the photo to the right.

    In the unusually high intensity dance in 2009 after the death of Phyl (a colt), 3-week-old Jacques danced with notable vigor. Jacques' moves were particularly interesting because he was not merely hopping and wing-waving, He was responsive to his partners and in precocious as he performed real dance steps, like the upright tuck, the one-wing spin, the spread-wing display, and the squat, as depicted on our Dance Display webpage.

=========
Based on our seven seasons of observations, we believe that the calendar dates shown are typical for cranes in Fairbanks.
Adults usually return from migration in the last week of April, begin incubaiton between May 3 and May 6, and colts hatch 31 days later. The cranes depart on their southward migration in the first few days of September.

Weeks 5 & 6 [~July 2-15]

  • Foraging - Colts wave their pin-feathered wings and run about following the adults and eagerly responding when the parents proffer food.   Oblio-08 is shown to the right.
  • Dance-Display - Adults dance and colts join in. In one of her first dances, Lucky-10 stumbled, as seen in Quicktime movie below. The parents were suddenly very attentive when Lucky fell.
    The stumble/tumble is shown clearly in the single pictures below, all taken from the Quicktime video sequence. The stumble and recovery occurred within a single realtime second. Lucky was starting to dance (left frame), fell (middle frame), and then recovered (looking crestfallen?) in right frame.








  • Caution - In week 5, the colts sleep under Millie's wings but in week 6, they usually sleep crouched on ground midway between the two parents who sleep standing on one leg about 3 meters apart.

=========
Based on our seven seasons of observations, we believe that the calendar dates shown are typical for cranes in Fairbanks.
Adults usually return from migration in the last week of April, begin incubation between May 3 and May 6, and colts hatch 31 days later. The cranes depart on their southward migration in the first few days of September.

Weeks 7 & 8 [~July 16-29]

  • Dance-Display - Colts repeatedly face off and dance with parents, as does 55-day-old Oblio-08 with Roy in the photograph to the right.
  • Foraging - Walkabout excursions may last overnight. The cranes feed heavily before the family sets off and colts seem quite tired after returning from these excursions. Foraging and feeding is almost constant in the day after such a field trip.
  • Foraging by colts - Colts start to forage semi-independently, wandering 10-15 meters from their parents to feed on blueberries and cranberries. They also begin to catch slower insects, like fritillary butterfles, as Lucky-10 demonstrates to the left. Throughout the summer, adults harvest many dragonflies, caught while perching or chased down on the wing. Colts don't acquire that skill in their first summer.
    • Flying - As colts run about, they frequently flap their wings. While doing so, they may jump and lurch into the air as their parents watch. See 43-day-old Jacques-09 jumping at the right.
    • Flight demos - Adults fly short distances as they lead the colt during foraging around the pond. They also do flight demonstrations: both parents fly in a circle over the pond and come back to the colt. The Quicktime movie below shows one of these flight demonstrations for Lucky-10 and the end of the 8th week.
      In the Quicktime sequence, Roy begins with a display that announces his "intent-to-fly" and points to the left. Then he runs past Lucky and takes flight as Lucky turns to follow his movements. Millie follows Roy and Lucky watches intently as they circle clockwise and come back. Roy lands in front of Lucky, with flapping and a few steps, and then checks-out the neighborhood in his Tall-alert display. After Millie lands, she walks over to Lucky and starts to look for insects in the grass.
    • Caution - "Flee and Hide"- Adults react strongly to intruders, as illustrated by Roy chasing a duck in photo to the right.
      In response to danger, colts sometimes run away from their parents and then hide. In 2006 while the parents faced off to danger threatening from the north, Barbaro turned and ran south across the bog away from his parents. Then he jumped into the pond, swam across 15 meters of open water, and hid in the cattails on the south shore.  The parents flew over to join him when the threat had passed.
      We see similar behavior every summer at this time with each successive colt. In 2010, Lucky was apparently "instructed" to swim across a bay while the parents faced off to an intrusion that was not at all visible to us. To a human observer, it seemed similar to a "fire drill". Once the "intruder" had gone, both parents flew to join Lucky who was hiding in the tall grasses. This evasive behavior practice may have paid off when a lynx appeared in August 2010 (see Weeks 11-13).
      Salim Ali has reported that when danger approaches, Sarus Crane chicks likewise hide in response to an alert from a parent (Ali S [1958] J. Bombay Nat. Hist. Soc. 55:166-168).

    =========
    Based on our seven seasons of observations, we believe that the calendar dates shown are typical for cranes in Fairbanks.
    Adults usually return from migration in the last week of April, begin incubation between May 3 and May 6, and colts hatch 31 days later. The cranes depart on their southward migration in the first few days of September.

    Weeks 9 & 10 [~July 30-August 12]

    • Flight demonstrations - In August, adults often fly as they move about within  their territory. They routinely poop, and flap their wings and, lastly, purr before signalling intent-to-fly.
    • Pre-flight coaching - At this age, colts seem restless, awkwardly flapping their big wings as they run about.

      At the end of the 8th week and over the next two weeks, the adults frequently dance with each other and/or with the colt, as if first to get the colt's attention and next to "coach" it by running and flapping in tandem while adults are in front of, beside, or behind the colt. To the right, Roy is ahead and Jacques-09 is behind.

      While running with a colt, the parents often lift off the ground, floating and gliding for a few meters. As the colt's wings catch air, it too can lift off for a short distance. In the second picture, both parents have spread their wings while Oblio-08 tries to catch air.
    • Foraging - Colts are still fed insects and vertebrate meat caught by a parent but they forage on their own for berries and grain, as far as 5-25 meters away from their parents.
    • Flying - In the first three frames of the Quicktime movie below, Roy (left) flaps his wings and takes a step; then Lucky-10 imitates. A run-flap coaching session follows.

      In frame 4, Millie is at the left; Roy is at the right holding out his wings, and Lucky is in the middle imitating Roy. Then Roy raises his wings as he starts to run and flap. Lucky chases with her wings out .
      By her fourth step, Lucky is trying to flap in Roy's cadence and she manages to synchronize with him as he passes out of view behind a spruce tree. Meanwhile, Millie coaches from behind.
      Lucky is almost gliding at the end of her run.

    • First flight - By weeks 9 & 10, colts are practicing at their own pace while the parents preen and eat nearby. Colts run and try awkward two-legged jumps to take off, as shown by Barbaro-06 to the right. He almost glides and appears to be bounding, then touching down, and then bounding again to cross the bog. With repeated practice and effort, the two-legged running jump succeeds and the colt lurches into the air.

      Colts usually make their first flight as a "solo" by mid-August.

    =========
    Based on our seven seasons of observations, we believe that the calendar dates shown are typical for cranes in Fairbanks.
    Adults usually return from migration in the last week of April, begin incubation between May 3 and May 6, and colts hatch 31 days later. The cranes depart on their southward migration in the first few days of September.

    Weeks 11 - 13 [~August 13 - September 3]

    • Flight practice - The next lessons are short flights within the nest territory. One such flight is shown in the Quicktime movie below, built from a sequence of still photographs.

      On the particular day in August 2009 when the photographs were taken, there were extensive forest fires nearby thus the cranes are seen through light smoke. Before the first frame, Roy and Jacques-09 walked from the grassy marsh on the right to the edge of a small bay.

      We don't mean to suggest that cranes have language akin to that of humans, but cranes do communicate with each other. In this case, we suggest that Roy encouraged the colt to follow him in a circuit around the pond.

    • In the Quicktime movie, Jacques watched as Roy flew across the bay and landed at water's edge. Then he followed Roy's example, flyng across the bay and landing in the grass behind the tree.

      Next come flights around the nest territory with the colt trailing a parent or with both parents flying along behind. If the colt takes off in the lead, Roy usually overtakes just before they land (photo right), as if to demonstrate landing technique.

    • Flight excursions - Several times each day in weeks 11-13, the crane family (with parents in the lead) flies excursions of a kilometer or two across the valley or (further east) up the valley. The parents precede their take-offs by an "intent-to-fly" display and then take flight, with colt following. On the outbound flights and on return (one to ten hours later), the parents often unison-call repeatedly. The colt follows a crane-length or two behind; they descend and land in the middle of the nest territory. In the photo to the right, Oblio-08, with an injured leg drooping slightly, is seen flying off with the adults on of these excursions.

      In weeks 12 and 13, the colt may give the intent-to-fly signal for an excursion.

      Colts appear tired after these excurions, often crouching-lying on the ground while feeding after return.

    • Sleeping - As we noted earier, very young colts sleep within the "tent" formed by a parents' wings (usually Millie) and at 2-3 week, they begin to sleep crouched down (lying) near their parents. The adults characteristically sleep standing on one leg.

      In August, colts sleep mostly lying down (for example after a tiring excursion) but in the last week of the month, they begin to sleep (probably just doze) on one leg. The stance is unsteady. The colt sways a bit and usually wakes up after only a few minutes, but it is learning.

    • Dance/Display - Every day, there is prolonged preening and dancing after eating. The colt is an active participant and an occasional initiator of dancing in weeks 12 and 13.
    • Interactions with neighboring cranes - Roy and Millie frequently unison-call and often they are answered from other cranes in the valley. Conversations become more frequent over the weeks and as migration becomes more imminent.

      On several occasions, other groups of cranes fly over, perhaps reflecting preliminary gatherings as a prelude to staging. Roy and Millie call energetically and may take flight, with the colt, to join the "intruder cranes". It is not clear whether they are chasing the intruders or forming a transient social relationship.

      In one instance, an intruder family landed on south side of the nest bog. Roy, Millie, and Lucky-10 flew over from the north shore and landed quite near the intruder-family, unison-calling (their usual behavior in territory defense). After a few seconds, the intruders moved 20 meters to the east. Perhaps out of confusion, Lucky followed and landed very close to the intruder family.

      Roy and Millie continued to unison-call, and the three intruders fled, flying south across the valley. To our surprise, Lucky followed the intruders as they left the nest territory.

      Now left at the nest pond without their colt, Roy and Millie unison-called excitedly and then circled the pond, following the exit path of the intruders. As they reached the half-way point across the valley (about a half-kilometer to the southeast), Lucky rose from the ground and flew along after her parents.

      Next day, the cranes' behaviors were normal. We have seen no other such "colt-napping" incidents.

    • Caution (Flee and Hide) - In weeks 7 & 8, we have watched colts "flee & hide", running away from their parents and then swimming across the pond as the parents face off to a "threat" that was not evident to us.

      In week 12 of 2010, we saw this "avoid danger" behavior in response to a threat that revealed itself. As the family was feeding in bog central, Roy and MIllie assumed the Tall-Alert posture, unison-called, and peered intently northwest into the forest. As we looked up, we could see no danger, no predator, nor could we see Lucky. Quite agitated, Roy and Millie flew to the west bog on the other side of the inlet.lynx   We were curious and waited.

      Seconds later a large animal, looking at first glance like a large stray dog, flashed onto bog central and ran to the east. It was a lynx (photo right). Then we spied Lucky across the pond on the south shore. The crane version of "fire drill" (see weeks 7-8) may have prepared Lucky to respond appropriately to a real threat.

    • Foraging - In weeks 12 and 13, foraging takes longer and longer, presumably to pack away energy reserves for migration. Over the past five years, Roy and Millie's departures have coincided with those of large flocks staging at Creamer's Field Refuge in Fairbanks.

    =========
    Based on our seven seasons of observations, we believe that the calendar dates shown are typical for cranes in Fairbanks.
    Adults usually return from migration in the last week of April, begin incubation between May 3 and May 6, and colts hatch 31 days later. The cranes depart on their southward migration in the first few days of September.

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