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Full-Text Articles in Population Biology
The Effect Of Disturbance On The Reproduction And Management Of Captive Cranes, Claire M. Mirande, James W. Carpenter, Ann M. Burke
The Effect Of Disturbance On The Reproduction And Management Of Captive Cranes, Claire M. Mirande, James W. Carpenter, Ann M. Burke
Proceedings of the North American Crane Workshop
A retrospective analysis of egg laying histories and observations of crane pairs at the International Crane Foundation and the Patuxent Wildlife Research Center indicates that disturbance associated with captivity has adverse impacts on captive breeding. Females on public display laid significantly fewer eggs than those off display (P < 0.05). Crane pairs moved to other pens (other than adjacent pens) or hetween facilities laid slightly fewer eggs than those birds which were not moved. although the results were not statistically significant (P = 0.188). Pen design and construction also appeared to have adverse impacts on breeding. In addition, human activities, intraspecific interactions, and rearing methods influence a bird's response to disturbance, and, therefore, these factors must also be considered in an effective crane management program. Modifying procedures to minimize disturbance, timing necessary disturbances after the breeding and molt seasons, and carefully monitoring birds for signs of stress can result in increased reproductive potential for captive, endangered cranes.
Monogamy And Productivity In Sandhill Cranes, Stephen A. Nesbitt, Thomas C. Tacha
Monogamy And Productivity In Sandhill Cranes, Stephen A. Nesbitt, Thomas C. Tacha
Proceedings of the North American Crane Workshop
Marked pairs of Florida (Grus canadensis pratensis) and greater sandhill cranes (G. c. tabida) were monitored for 426 pair-years. Among pair members, females averaged 3.7 ± 3.6 (SD) years older than males. Pair longevity was not correlated with pair productivity (P ~ 0.279) for pairs that were together >3 years. Forty-four percent of 72 Florida sandhill crane pair bonds were broken during the study, 67.7% due to death and 32.3 % to divorce. Among both Florida and greater sandhill cranes, the incidence of divorce was related to a failure to reproduce; 52.6% of pairs that failed to produce …
Recent Advances In Scheduling Strategies And Practical Techniques In Crane Artificial Insemination, Scott R. Swengel, Monica L. Tuite
Recent Advances In Scheduling Strategies And Practical Techniques In Crane Artificial Insemination, Scott R. Swengel, Monica L. Tuite
Proceedings of the North American Crane Workshop
We analyzed fertility patterns of 339 eggs laid 1985-93 at the International Crane Foundation by cranes whose sole means of fertility was artificial insemination (AI). Ten of 15 crane species were studied. Fertility rates increased significantly (P < 0.05) with (I) higher sperm density, (2) greater sperm motility, and (3) 2 vs. 1 vs. 0 inseminations 4-7 days before oviposition. Semen sample size was inversely related to sperm density and had no strong relationship with egg fertility. Inseminations less than 2.5-3.0 days before an egg is laid are probably too late to contribute to fertilizing the egg but may contribute substantially to fertilizing the next egg. We also describe practical knowledge gained during the past 10 years that apply to certain species or situations. Wattled cranes (Bugeranus carunculatus) have a long fertile period post-AI (up to 16 days), but may require more careful methods and special AI scheduling strategies. We also describe techniques for AI just after oviposition that are especially beneficial for Siberian cranes (Grus leucogeranus), and methods for maximizing sample delivery to the female.
An Experimental Release Of Whooping Cranes In Florida - The First Three Years, Stephen A. Nesbitt, Martin J. Folk, Marilyn G. Spalding, James A. Schmidt, Stephen T. Schwikert, Jane M. Nicolich, Marianne Wellington, James C. Lewis, Tom H. Logan
An Experimental Release Of Whooping Cranes In Florida - The First Three Years, Stephen A. Nesbitt, Martin J. Folk, Marilyn G. Spalding, James A. Schmidt, Stephen T. Schwikert, Jane M. Nicolich, Marianne Wellington, James C. Lewis, Tom H. Logan
Proceedings of the North American Crane Workshop
Fifty-two juvenile whooping cranes (Grus americana) were soft-released in Florida from February 1993 to April 1995. The birds were released in groups ranging in size from 5 to 14 individuals. The first-year survival rate was 0.42 for all years combined. First-year rates for each year were 0.36 for 1993, 0.32 for 1994, and 0.47 for 1995. Most mortality (62%) occurred during the first 3 months following release. The survival rate of 0.81 the second year after release was similar to that of Florida sandhill cranes (G. canadensis pratensis) (0.87). Predation by bobcats (Lynx rufus) …
Vocalizations Of Sandhill Cranes, Stephen A. Nesbitt, Richard A. Bradley
Vocalizations Of Sandhill Cranes, Stephen A. Nesbitt, Richard A. Bradley
Proceedings of the North American Crane Workshop
The structure and context of 20 vocalizations given by adult or juvenile sandhill cranes (Grus canadensis) are described. Purr calls were given under various circumstances (e.g., pre-flight, feeding, aggression) and communicated information over a short distance. Flight calls, guard calls, and urtison calls were full-voiced calls that carried information over greater distances. Calls given in flight were distinguishable from other calls. Guard calls were given in several different circumstances and served multiple functions; other calls were given in very specific contexts. Beyond the basic communication of information to other cranes, vocalizations may function in mate selection and in …