Geology topics

M. Kinloch

Publications and source records attributed to M. Kinloch.

4 recordsLinked to original sources

USGS2006

Head-bobbing behavior in foraging Whooping Cranes

Many species of cursorial birds 'head-bob', that is, they alternately thrust the head forward, then hold it stiII as they walk. Such a motion stabilizes visual fields intermittently and could be critical for visual search; yet the time available for stabilization vs. forward thrust varies with walking speed. Whooping Cranes (Grus americana) are extremely tall birds that visually search the ground for seeds, berries, and small prey. We examined head movements in unrestrained Whooping Cranes using digital video subsequently analyzed with a computer graphical overlay. When foraging, the cranes walk at speeds that allow the head to be held still for at least 50% of the time. This behavior is thought to balance the two needs for covering as much ground as possible and for maximizing the time for visual fixation of the ground in the search for prey. Our results strongly suggest that in cranes, and probably many other bird species, visual fixation of the ground is required for object detection and identification. The thrust phase of the head-bobbing cycle is probably also important for vision. As the head moves forward, the movement generates visual flow and motion parallax, providing visual cues for distances and the relative locations of objects. The eyes commonly change their point of fixation when the head is moving too, suggesting that they remain visually competent throughout the entire cycle of thrust and stabilization.

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USGS2001

Results of the Utah-Arizona stage-by-stage migrations

In an effort to find a safer means of teaching cranes new migration routes, each year (in 1998 and 1999) we transported a group of greater sandhill cranes (Grus canadensis tabida) stage-by-stage, in a horse trailer, with stops for brief flights at about 30-km intervals, along a 1300-1400-km fall migration route from Fish Springs National Wildlife Refuge (Fish Springs) in west-central Utah to the vicinity of Gila Bend, Arizona. Thereafter, we released them into a wild flock of sandhill cranes. All stage-by-stage birds were hand-reared with both a plastic crane decoy (to encourage them to roost in water) and a costume-draped humanoid form (called a scare-eagle and used for its namesake purpose). When these 2 teaching aids were placed in water, our cranes readily roosted nearby. All but 4 of our cranes proved cooperative (i.e., catchable at each of the ca 25-36 stops) during the migration. All were efficiently released into a wild flock and experienced good survival. The stage-by-stage method proved to be a safe means of transporting cranes south and giving them experience along the route. Some cranes apparently learned their route from the limited experience afforded by releasing them at intervals, and the 1999 cranes have made repealed migrations to or near our chosen northern terminus. However, after 1 winter in our chosen area, the birds have moved elsewhere to winter.

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USGS2001

The one-by-one method for releasing cranes

Although the trend for the past 2 decades has been toward releasing naive groups of juveniles after a lengthy acclimation period, in 5 separate releases (1996-2000) we tested the idea that naive juvenile greater sandhill cranes (Grus canadensis tabida) would survive better if released singly into a wild flock of predator-wary birds than if left as a group, inexperienced at foraging and ill prepared to avoiding predators. We released 3 groups of hand-reared juveniles (n = 12 [1996]; n = 8 [1998], n = 12 [1999]) into a wild flock of sandhill cranes (ca 300 birds) on wintering grounds near Gila Bend, Arizona. Another 8 parent-reared colts were released into a small group (4) of subadult greater sandhill cranes (survivors of the 1996 trucking experiment [Ellis, et al. 1997; Ellis et al. 2001, Mummert et al. 2001]) in northcentral Arizona. Another 8 juveniles, costume-reared from hatching, were released into wild sandhill crane flocks in central Wisconsin at autumn staging areas. In all of these tests, cranes were released 1 or 2 at a time, either at the periphery of a wild flock or at a known roost site. Most birds were released in daylight at a foraging area, but because this was a pilot project, we tried a variety of methods. We released a few individuals at odd times (e.g., midnight) and in odd ways (e.g., by flushing a release crane as a wild flock passed overhead). A few birds were initially left stranded after we placed them at ephemeral roosts that had been used recently, but not subsequent to our visit. However, once we made the necessary adjustments, and regardless of release time or situation, all of our cranes very quickly joined their adoptive flocks. We experienced excellent survival, including 100% survival for all 8 of our parent-reared fledgling colts released on the summering ground and followed until they disappeared at the time of migration. Further, all (32) hand-reared birds released on the wintering grounds survived the winter. Also all 8 of the juveniles reared and released in Wisconsin successfully migrated south and returned north to Central Wisconsin the following spring. These results recommend the one-by-one method as a promising strategy for releasing juvenile cranes with minimal training, handling, and maintenance. The method provides a likely strategy for building wild flocks of endangered cranes once a core group is established by some other method.

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USGS1997

Results of an experiment to lead cranes on migration behind motorized ground vehicles

Ten greater sandhill cranes (Grus canadensis tabida), trained to enter and ride in a specially equipped truck, were transported at 80? days of age from their rearing site at Patuxent Wildlife Research Center (Patuxent), Maryland, to a reintroduction site located within the species? former breeding range in northern Arizona. After 5 additional weeks of training, these juvenile cranes were led south ca 600 km to a wintering area on the Arizona/Mexico border. Nine of the 10 survived the trek, 495 km of which was flown, although only a few cranes flew every stage of the route. Their longest flight was 77 km. Major problems during the migration were power line collisions (three, one fatal), eagle attacks (none fatal), and overheating (when air temperatures exceeded ca 25?C). All cranes that entered training quickly learned to follow the truck, and their tenacity when following under unfavorable conditions (e.g., poor light, extreme dust, or heat) showed that cranes could consistently be led over long distances. We cannot predict if the cranes will retrace their route unassisted when adults, but 2 cranes returned 130 km to the starting point of the migration after the flock was scattered by an eagle during our migration south. Three other cranes were recovered 55 km from the attack site and on course toward the starting point.

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