In the face of global biodiversity declines, conservation measures are urgently needed. However, our lack of knowledge on species’ diversity, distributions and population trends presents a major obstacle, particularly for morphologically cryptic species. Field surveys to gather this information present a logistical challenge, but the rapid rise of citizen science presents a new opportunity, generating huge volumes of data rapidly across a species’ range. We use data from a national citizen-science project to document the distribution and advertisement call variability in a group of five morphologically conserved treefrogs. Using 542 male advertisement calls across the entire range of five species, we found considerable levels of acoustic variation both among and within species. Note shape, notes per call and positions of the longest and shortest notes were most useful to delineate species. Our research will assist in species delineation and identification in the field and form the basis for a more accurate understanding of species diversity and distributions in the brown tree frog complex. We also demonstrated the utility of citizen science in documenting species distributions and diversity.

Large (>3 m) slender-bodied rat snakes are abundant in agroecosystems of southern Asia and are heavily exploited for their skins and meat. We examined 216 specimens killed at commercial facilities in Cirebon, West Java, to quantify morphological and reproductive traits and evaluate harvest sustainability by comparing this sample to one taken 25 years previously. The snakes we examined were mostly adults, and mostly male. Females were less heavy-bodied than males of the same body length, matured at a larger size than males, but attained smaller maximum sizes. Reproduction and energy (fatbody) storage was seasonal in both sexes, with females containing oviductal eggs primarily during the annual wet season. Clutch size averaged 12.6 eggs and increased with maternal body size. Comparison of the two samples taken 25 years apart revealed strong similarity in sex ratio, the numerical preponderance of adults, body sizes at sexual maturation and mean adult body sizes, sexual dimorphism in body length and mass, reproductive seasonality in females, mean fecundity, and the relationship between fecundity and maternal body size. That consistency suggests that commercial harvesting over the intervening period has not affected the biological traits of rat snake populations, consistent with a sustainable level of offtake.