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Full-Text Articles in Population Biology
Florida Sandhill Crane Relocates Egg During Incubation, Timothy A. Dellinger, Miranda L. Watford, Ronald R. Bielefeld
Florida Sandhill Crane Relocates Egg During Incubation, Timothy A. Dellinger, Miranda L. Watford, Ronald R. Bielefeld
Proceedings of the North American Crane Workshop
Anecdotal accounts of birds moving their eggs to a new location have been reported in shorebirds, waterfowl, and woodpeckers. We report relocation of an egg, 2 days prior to hatching, by an adult Florida sandhill crane (Grus canadensis pratensis). We do not know why the egg was moved, but egg movement among other species appears to be associated with nest disturbance by humans, animals, or environmental conditions.
Timing Of Molt In Florida Sandhill Cranes, Stephen A. Nesbitt, Stephen T. Schwikert
Timing Of Molt In Florida Sandhill Cranes, Stephen A. Nesbitt, Stephen T. Schwikert
Proceedings of the North American Crane Workshop
We observed feather molt in Florida sandhill cranes (Grus canadensis pratensis) between 1978 and 1997. We report data from 4 feather groups: remiges, rectrices, wing coverts and contour feathers. In all feather groups, the median date of ecdysis preceded endysis by about 30 days. Endysis in adults was generally later than it was in first- or second-year subadults. Remiges grew at a rate of 4.72 ± 1.56 SD mm per day. We estimated that primary and secondary wing feathers were usually regenerated within 45 to 70 days.
Survival And Sources Of Mortality In Florida Sandhill Crane Chicks – Hatching To Fledging, Stephen A. Nesbitt, Stephen T. Schwikert, Marilyn G. Spalding
Survival And Sources Of Mortality In Florida Sandhill Crane Chicks – Hatching To Fledging, Stephen A. Nesbitt, Stephen T. Schwikert, Marilyn G. Spalding
Proceedings of the North American Crane Workshop
Forty-five pairs of Florida sandhill cranes (Grus canadensis pratensis) were monitored during the nesting seasons from 1996 through 1999. Thirty-eight chicks were produced from 25 successful nests. Twenty-one of these survived to fledging age. Predation was the source of most (81%) of the mortality for which a cause was determined. Mammals were the primary predator. Average age at time of mortality was 27.2 days for the 17 chicks lost.
Interaction Of Young Florida Sandhill Cranes With Their Parents, Stephen A. Nesbitt, Paul S. Kubilis, Stephen T. Schwikert
Interaction Of Young Florida Sandhill Cranes With Their Parents, Stephen A. Nesbitt, Paul S. Kubilis, Stephen T. Schwikert
Proceedings of the North American Crane Workshop
We studied the interactions of 46 Florida sandhill crane (Grus canadensis pratensis) chicks and their parents from hatching until the chicks left the family group. Our goal was to see if young remained closer to one parent than the other and if the distance between a chick and its parents increased as the young approached the age of independence. Using a population of individually marked adult pairs, we ranked the distance to and gender of the nearest parent during 233 30-minute observation periods. Between hatching and 180 days of age, chicks showed a greater tendency to be nearer …
Body Mass Index (Bmi) Of Normal Sandhill Cranes, Stephen A. Nesbitt, Marilyn G. Spalding, Kristen L. Candelora, Paul S. Kubilis, Stephen T. Schwikert
Body Mass Index (Bmi) Of Normal Sandhill Cranes, Stephen A. Nesbitt, Marilyn G. Spalding, Kristen L. Candelora, Paul S. Kubilis, Stephen T. Schwikert
Proceedings of the North American Crane Workshop
We used linear and mass measurements to construct a body mass index (BMI) for 2 subspecies of sandhill cranes (Grus canadensis). We found that BMI declined during the spring and early summer period. We used the BMI to show that juvenile Florida sandhill cranes (G. c. pratensis) reach their full mass at about 270 days of age, near the age at which they begin to leave the company of their parents. We used mensural data to predict a minimum expected mass for normal sandhill cranes which could be then used to evaluate the relative health of …
Trends In Habitat And Population Of Florida Sandhill Cranes, Stephen A. Nesbitt, James L. Hatchitt
Trends In Habitat And Population Of Florida Sandhill Cranes, Stephen A. Nesbitt, James L. Hatchitt
Proceedings of the North American Crane Workshop
To map the areas of potential occupied habitat for Florida sandhill cranes (Grus canadensis pratensis) in Florida we used known habitat requirements and confirmed locations of occurrence in combination with a Geographic Information System. Using the map of potential habitat resulting from this process, we calculated the changes in the amount and distribution of crane habitat in Florida in 10-year increments since 1974. Based on annual home range sizes, age structure, and average flock size, we estimated the statewide population of Florida sandhill cranes in 2003 to be 4,594 individuals. Considering the area of crane habitat lost since …
Morbidity And Mortality Factors In Pre-Fledged Florida Sandhill Crane (Grus Canadensis Pratensis) Chicks, Robert J. Dusek, Marilyn G. Spalding, Donald J. Forrester, Nicholas Komar, Jonathan F. Day
Morbidity And Mortality Factors In Pre-Fledged Florida Sandhill Crane (Grus Canadensis Pratensis) Chicks, Robert J. Dusek, Marilyn G. Spalding, Donald J. Forrester, Nicholas Komar, Jonathan F. Day
Proceedings of the North American Crane Workshop
One hundred and fifteen Florida sandhill crane (Grus canadensis pratensis) chicks were captured in Osceola and Lake Counties, Florida in 1998 - 2000 and examined for evidence of disease. Evidence of Eimeria gruis and/or E. reichenowi infection was found in 52% of chicks examined. Ten chicks were positive for antibodies to St. Louis encephalitis virus and 1 of these chicks was also positive for antibodies to eastern equine encephalitis virus. Predation was the most commonly identified cause of mortality. An unidentified microfilaria, and an unknown protozoan were detected in blood smears from crane chicks. A number of other …
Age, Sex, And Aggression In Florida Sandhill Cranes, Stephen A. Nesbitt
Age, Sex, And Aggression In Florida Sandhill Cranes, Stephen A. Nesbitt
Proceedings of the North American Crane Workshop
Individually directed aggressive interactions were recorded for sandhill cranes in Florida over a 9-year period. Charges and stabs were the most frequently observed aggressive behaviors. Paired adults initiated most of the encounters. Males directed 67% of aggressive interactions toward other males and 84% of female aggressive interactions were directed toward other females. The sex of initiator was significantly correlated with the sex of the receiver (P = 0.001). Paired adults directed most aggression (64.7%) toward other paired adults. Aggression initiated by subadult cranes was directed toward adults and subadults with equal frequency. The aggressiveness in males as an indicator of …
Response Of Florida Sandhill Cranes To Nest Inspection, Stephen A. Nesbitt, Paul S. Kubilis, Stephen T. Schwikert
Response Of Florida Sandhill Cranes To Nest Inspection, Stephen A. Nesbitt, Paul S. Kubilis, Stephen T. Schwikert
Proceedings of the North American Crane Workshop
We observed the response of nesting Florida sandhill cranes (Grus canadensis pratensis) to 27 instances of nest inspection. The disturbed bird flew from the area 81% and walked 19% of the time. The median distance moved was 330 meters (range 28 to 480 meters). The median length of time the nest was left unattended following inspection was 50 min (range: 10 to 166 min). The median length of time that observers stayed at the nest was 16 min (range: 5 to 48 min). Ten of the nests inspected (40%) eventually failed to produce young. Statistical analysis was focused …
The Effects Of Semen Collection On Fertility In Captive, Naturally Fertile, Sandhill Cranes, Guojun Chen, George F. Gee, Jane M. Nicolich, Joanna A. Taylor
The Effects Of Semen Collection On Fertility In Captive, Naturally Fertile, Sandhill Cranes, Guojun Chen, George F. Gee, Jane M. Nicolich, Joanna A. Taylor
Proceedings of the North American Crane Workshop
We tested to see if semen collection interferes with fertility in naturally fertile pairs of cranes. We used 12 naturally fertile, Florida sandhill crane (Grus canadensis pratensis) pairs for this study, 6 control and 6 experimental. All pairs had previously produced fertile eggs. Semen was collected on Tuesday mornings and Friday afternoons from 26 February 1993 to 4 June 1993. We used standard artificial insemination methods to collect and to evaluate the semen and spermatozoa. Semen collection had minimal effect on semen quality and semen quantity. Semen volume, sperm density, sperm motility, sperm morphology, sperm viability, sperm number …
Aspects Of Reproduction And Pair Bonds In Florida Sandhill Cranes, Stephen A. Nesbitt, Martin J. Folk, Stephen T. Schwikert, James A. Schmidt
Aspects Of Reproduction And Pair Bonds In Florida Sandhill Cranes, Stephen A. Nesbitt, Martin J. Folk, Stephen T. Schwikert, James A. Schmidt
Proceedings of the North American Crane Workshop
From 1980-98 we captured and uniquely marked more than 400 Florida sandhill cranes (Grus canadensis prafensis). Age ratios of the marked population, excluding juveniles, was 66% adult and 33% subadult, and the sex ratio was 49% male and 51% female. Average clutch size for 210 nests checked from 1983-97 was 1.78 ± 0.18 (SD) and frequency of l-egg clutches varied among years. Average post-fledging brood size from 1991 to 1997 was 1.27 ± 0.17 (SD), included a 3-chick brood. Average percent ofYOlmg from 2 study areas, 1991-97 was 11.9 ± 3.23 (SD). We observed renesting up to 3 …
Habitat Use By Florida Sandhill Cranes On The Kissimmee Prairie In Central Florida, Mary Anne Bishop
Habitat Use By Florida Sandhill Cranes On The Kissimmee Prairie In Central Florida, Mary Anne Bishop
Proceedings of the North American Crane Workshop
Radio-tagged Florida sandhill cranes (Grus canadensis pratensis) were monitored for habitat use during 1985 and 1986 on the Kissimmee Prairie in central Florida. For both breeding and nonbreeding cranes, 93 % of the daytime locations were in 3 habitat types: cropland and plowed pasture, improved pasture, and palustrine emergent wetlands. Improved pasture was the most frequently used daytime habitat for both social classes. Radio locations were divided among 4 time blocks (3 diurnal, 1 nocturnal) and 4 3-month seasons. Time-of-day effects for use of wetlands and improved pasture were only marginally significant (1' < 0.08 and l' < 0.09, respectively) for breeders and not significant (1' < 0.30 and l' < 0.43, respectively) for nonbreeders. There was no significant difference in habitat use by breeders among seasons. Chi-square analyses of diurnal locations indicated that 4 of the 6 breeding cranes monitored used palustrine emergent wetlands more than their availability. The selection for wetlands reflects not only the rich food sources available, but also their use as midday loafing and drinking sites and as a source of cover that the upland habitats do not offer.
Food And Feeding Habits Of Released Florida Sandhill Cranes, Christine R. Rucker
Food And Feeding Habits Of Released Florida Sandhill Cranes, Christine R. Rucker
Proceedings of the North American Crane Workshop
Food habits of 4 pairs of free-ranging Florida sandhill cranes (Grus canadensis pratensis) on St. Catherine's Island, Georgia, were studied from May to October 1990. Food items were identified and quantified at close range « 10 m). The 4 pairs varied in how they used plant and animal resources (P < 0.0001). Animal material in the diets averaged 19.1 % and ranged from 13.4 to 36.7%. Plant material averaged 80.9% in the pairs' diets. Major foods included subsurface bulbs, roots, and tubers of yellow star grass (Hypoxis micrantha), catbrier (Smilax glauca), and false garlic (Allium bivalva), longleaf pine seeds (Pinus palustris), and insects. Food habits shifted seasonally for all pairs (P < 0.(001). In July and August the percent occurrences of yellow star grass and false garlic in the diets were > 50 %. During September and October pine seed occurrence was > 75 % in the diets of …