News from Scientists at the USGS Patuxent Wildlife Research Center
Friday, May 23, 2003
Crane Breeding Season Update
Week of May 19: As of Monday, May 19, we have 15 chicks in the Whooping Crane Eastern Partnership (migration) program. Two of these chicks were produced from eggs sent to us from the San Antonio Zoo, and one of them is from an egg send to us from the International Crane Foundation. Several of the chicks are over 20 days old already and quite tall, while the 2 youngest hatched today. All 15 chicks are doing well, in spite of many days of cold, rainy weather that made it very hard to get the chicks enough exercise or training time with the plane. If the chicks don't get enough exercise time it jeopardizes the development of their legs, and if they don't get enough training time with the plane it jeopardizes their attachment to it. The crew has managed to work around the elements, and so far the chicks are doing well. Included are some pictures of the chicks training with the plane, and being taken to the pond so they can get some necessary water exposure. The 6 Florida sandhill crane chicks that were raised for a glider study in cooperation with the International Crane Foundation, were transported to California for glider training. They were about 25 days old when they left, healthy and strong. We all hope they'll like California. Current whooping crane egg production is at 49 eggs from 10 producing females. Twenty eggs are known to be fertile. Contact Kathleen O’Malley, Laurel, MD, 301-497-5609 Publication by Patuxent Scientists: Estimation by Capture-Recapture of Recruitment and Dispersal Over Several Sites Lebreton J.D.; Hines J.E.; Pradel R.; Nichols J.D.; Spendelow J.A.; Oikos, May 2003, vol. 101, no. 2, pp. 253-264(12). Abstract: Dispersal in animal populations is intimately linked with accession to reproduction, i.e. recruitment and population regulation. Dispersal processes are thus a key component of population dynamics to the same extent as reproduction or mortality processes. Despite the growing interest in spatial aspects of population dynamics, the methodology for estimating dispersal, in particular in relation with recruitment, is limited. In many animal populations, in particular vertebrates, the impossibility of following individuals over space and time in an exhaustive way leads to the need to frame the estimation of dispersal in the context of capture-recapture methodology. We present here a class of age-dependent multistate capture-recapture models for the simultaneous estimation of natal dispersal, breeding dispersal, and age-dependent recruitment. These models are suitable for populations in which individuals are marked at birth and then recaptured over several sites. Under simple constraints, they can be used in populations where non-breeders are not observed, as is often the case with colonial waterbirds monitored on their breeding grounds. Biological questions can be addressed by comparing models differing in structure, according to the generalized linear model philosophy broadly used in capture-recapture methodology. We illustrate the potential of this approach by an analysis of recruitment and dispersal in the roseate tern Sterna dougallii. Contact Jeffrey
Spendelow, Laurel, MD, 301-497-5665 (for Roseate Tern biology) Publication by Patuxent Scientist: Contact Don Sparling, Laurel, MD, 301-497-5723 |
Publication by Patuxent Scientists: Local Extinction and Turnover Rates at the Edge and Interior of Species’ ranges: Paul F. Doherty, Jr., Thierry Boulinier, and James D. Nichols, Ann. Zooi. Fennici 40: 145-153. Abstract: One hypothesis for the maintenance of the edge of a species’ range suggests that more central (and abundant) populations are relatively stable and edge populations are less stable with increased local extinction and turnover rates. To date, estimates of such metrics are equivocal due to design and analysis flaws. Apparent increased estimates of extinction and turnover rats at the edge of range, versus the interior, could be a function of decreased detection probabilities alone, and not of a biological process. We estimated extinction and turnover rates for species at the interiors and edges of their ranges using an approach which incorporates potential heterogeneity in species detection population. Extinction rates were higher at the edges (0.17 + 0.03 [SE]) than in the interiors (0.04 + 0.01), as was turnover. Without taking the probability of detection into account these differences would be artificially magnified. Knowledge of extinction and turnover rates is essential in furthering our understanding of range dynamics, and in directing conservation efforts. This study further illustrates the practical application of methods proposed recently for estimating extinction rates and other community dynamic parameters. Contact James Nichols, Laurel, MD, 301-497-5660
Publication by Patuxent
Scientists: Contact James Nichols, Laurel, MD 301-497-5660 Eastern Region Special Emphasis Program Advisory Committee (ER-SEPAC) Meeting On May 12-14, the ER-SEPAC conducted a working meeting at Patuxent Wildlife Research Center (http://www.pwrc.usgs.gov/) in Laurel, Maryland. Regina Lanning, (Liaison for the Disability Program in SEPAC) Communication Assistant at PWRC participated in the meeting with 8 other members to develop plans for completing the committee's report on opportunities and barriers related to career development in the USGS. The final report will be available to Survey employees later this fiscal year. The meeting agenda included a team-building seminar, conducted by the Office of Employee Development. There also was a meeting with PWRC staff to introduce SEPAC, describe the purpose and approach, and to answer questions. The ER-SEPAC's new Web site went live this week at http://ergnet.er.usgs.gov/tsb/ersepac/index.htm. Contact Regina Lanning, Laurel, MD, 301-497-5509 Australian Coastal Scientist to Visit Patuxent Wildlife Research Center Dr. Neil Saintilan from Australian Catholic University, New South Wales, Australia will be visiting Patuxent Wildlife Research Center (PWRC) from June 14 to June 25, 2003. Dr. Saintilan is collaborating with Dr. Donald R. Cahoon, a coastal ecologist at PWRC, in monitoring salt marsh and mangrove elevation dynamics in relation to rising sea levels at several coastal areas in eastern Australia. The 72 monitoring stations in Australia, the only stations in the southern hemisphere, represent a significant contribution to an international network of monitoring stations established in 15 countries by Dr. Cahoon and his colleagues. Dr. Saintilan will present a seminar on his research program in Australia, visit salt marsh elevation monitoring stations located along the U. S. Atlantic coast, and learn about new advances in elevation monitoring technology developed in Dr. Cahoon's lab. For further information on Dr. Saintilan's visit, contact Dr. Cahoon at 301-497-5523 or don_cahoon@usgs.gov . Contact Don Cahoon, Laurel, MD, 301-497-5523 |
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