Under the wing of science: Two methods for aging nestling Carnaby’s cockatoo species

Multi-year research on two populations of the endangered endemic Carnaby’s cockatoo in southwestern Australia was conducted in order for two separate methods for nestlings aging to be assessed. If accurate enough, Dr. Denis Saunders and his team believe that the results could be vital in the threatened species’ preservation, as explained in the Carnaby’s cockatoo’s recovery plan.

One of the methods they have looked into is based on changes in the physical appearance of nestlings over the 10-11 week nestling period. The other relies on measurements of a nestling’s folded wing length and its comparison with growth curves from measurements of nestlings of known age. In their paper the Australian team also examines the timing and length of the egg-laying season. Their research is published in the open-access journal Nature Conservation.

The researchers point out that accurate nestling aging is essential for many ecological studies. The data could be used in investigating population dynamics, life histories, behaviour, longevity, conservation planning and management. It could also help in scheduling the visits of breeding areas so that the disturbance for the populations is minimised without compromising the results.

The scientists found out that observing the changes in a nestling’s size and feathers is less accurate than measuring the folded wing length. Its main disadvantage turned out to be the lack of distinguishable physical changes once the birds become about nine-week-old. However, “with experience it may be useful for gaining an approximation of the commencement and end of the breeding season without having to handle nestlings to take measurements,” the team says.

Their research on the egg-laying dates concluded that the most effective approach for examining nestlings is to conduct two visits per breeding season. Curiously, their findings showed that in wetter autumns the egg-laying begins earlier.

The team also suggests that their methods could be adopted for aging the currently under-researched closely related Baudin’s cockatoo until more species-specific technique is found.

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Original source:

 

Saunders DA, Dawson R, Nicholls AO (2015) Aging nestling Carnaby’s cockatoo, Calyptorhynchus latirostris, and estimating the timing and length of the breeding season.Nature Conservation 12: 27-42. doi: 10.3897/natureconservation.12.4863

Cave snail from South Korea suggests ancient subterranean diversity across Eurasia

As tiny as 1.7 mm, a snail whose relatives live exclusively in the deep recesses of caves, provided a sensational discovery from the depths of Nodong cave, South Korea, back in 2000 for its collector, J. S. Lee. It is the only cave-dwelling representative of the family of hollow-shelled snails in the whole of Asia with its closest relatives known from as far as Croatia and Northern Spain. The scientists, Adrienne Jochum, Bern University and Natural History Museum Bern, Larisa Prozorova and Mariana Sharyiool from the Far Eastern Russian Academy of Sciences and Barna Páll-Gergely from Shinshu University, published its description in the open-access journalZooKeys.

The Asian species has awaited 15 years to come out of the dark for a name and into the limelight of subterranean biodiversity and conservation awareness. This barely visible snail suggests a former pan-Eurasian distribution of cave-dwelling, hollow-spired snails.

The tiny-shelled treasure, called Koreozospeum nodongense, belongs to a larger group of ancient cosmopolitan air-breathing relatives known to have been amongst the first snail colonisers of land via mangroves about 65 million years ago. Similar to its European relatives from the genus Zospeum, the South Korean snail was also found on muddy cave walls.

Although more than 1,000 caves have been explored in South Korea, Nodong is so far the only one to harbour these beautiful denizens of the dark. Hypotheses made by Culver et. al. in 2006 about the existence of a very narrow, mid-latitudinal ridge of subterranean biodiversity (ca. 42-46°N in Europe and 33-35°N in North America) might clarify this unique find.

A high amount of caves known to exist within these latitudes provide ample habitats for colonisation of life. If this hypothetical ridge were to be extended further East away from Europe, then Koreozopseum‘s gliding along walls in a South Korean cave (33-35°N) makes a strong call for further investigations and discovery of rare biodiversity.

Jochum and her international team described K. nodongense using computer tomographic scans (Nano-CT) in a video film to view and compare the contours and architecture of the very fragile shell. Chemical trace elements, such as aluminum (Al) and silicon (Si) were detected in other scans of the thin diaphanous shell using mineralogical analysis techniques (SEM-EDX). These elements may play a role in the biomineralization (hardness) of the shell or may be contaminants absorbed by the snail from sediment consisting of volcanic ash from former eruptions in the region.

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Original Source:

Jochum A, Prozorova L, Sharyi-ool M, Páll-Gergely B (2015) A new member of troglobitic Carychiidae, Koreozospeum nodongense gen. et sp. n. (Gastropoda, Eupulmonata, Ellobioidea) is described from Korea. ZooKeys 517: 39-57. doi: 10.3897/zookeys.517.10154

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Additional information:

The Naturhistorisches Museum der Burgergemeinde Bern, Switzerland and the Far Eastern Branch of the Russian Academy of Sciences supported this work.