At 6:03 pm, President Barbara Saunders called the meeting to order and asked those attending the lecture whether or not they were members of the Society. The majority were members. Vice-President Ken Chaya then introduced Shawn Billerman of the Cornell Laboratory of Ornithology. His talk “What Hybridization in Birds can tell us about Biodiversity, Climate Change and Evolution” described the results of his group’s analysis of bird hybridization zones, in the Great Plains, between the sister species of Bullock’s and Baltimore Orioles and Spotted and Eastern Towhees. Shawn pointed out that some ten percent of recognized bird species can hybridize with closely related species. This hybridization can yield important clues as to the drivers and consequences of speciation, one of the most important questions in Evolution. The Great Plains offer an important laboratory for such studies, as the ranges of allopatric species, formerly separated by the ice-sheets of the last Ice Age, overlapped once the ice disappeared. Of particular importance is the Platte River Basin, where a corridor of trees has allowed species such as the Orioles and Towhees to spread from their ancestral ranges. Extensive historical collections are available for both pairs of species and their respective hybrids. In addition, historical climate data are also available. These data sets allow comparisons of the former and current ranges of the hybrid zones and comparisons with any changes in climate. The data strongly suggest that climate change has a significant effect on the hybrid zone range of the Orioles, but not of the Towhees. Turning to DNA analysis of individuals in the current hybrid zones, Shawn demonstrated that the Orioles show a marked skew in the frequency of particular parental genetic markers, with Bullock’s markers declining rapidly from west to east and conversely Baltimores’ markers declining from east to west. This suggests that there is strong selection pressure against hybrids, although the nature of that selection is unknown. Towhees on the other hand show no such skew in the data, suggesting that all forms of hybrid are selectively neutral. The different outcome for the two species may lie in intrinsic factors, such as the overall genetic distance between the two pairs of species. It is of note that the mitochondrial DNA of the two Oriole species is some 2% different, while that of the Towhees is only 1%. Intrinsic genetic differences might affect mate choice, migration patterns and molting times. Alternatively, the explanation for the apparent selection in the Oriole pair may lie in extrinsic factors such as the tolerance of Bullock’s Orioles to higher temperatures.
At 7:30 pm President Barbara Saunders reconvened the meeting. Recording Secretary Hamish Young read the minutes of the September meeting. They were approved, after a correction made by Council Member Chuck McAlexander. Secretary Lydia Thomas presented three candidates for membership, Amy Simmons, sponsored by Gabriel Willow, and Amanda Bielskas, sponsored by Rochelle Thomas, both for active membership and Kathy Mele, sponsored by Gabriel Willow for supporting membership. The applications were approved unanimously. President Saunders announced that copies of the Proceedings were available to members. She also pointed out an error in the Schedule of Events: the Annual Meeting and Dinner is on March 10th, not 12th, as printed in the Schedule. President Saunders expressed her thanks to Council Member Kathleen Matthews for organizing the excellent Homecoming Picnic and to Vice President Chaya and Council Member Willow for organizing the quiz and the nature walks. She also thanked Frances Lee Rogers for looking after the feeders in the Evodia Field in Central Park. The feeders are expected to be available by the end of October. President Saunders also reported that a Spotted Lantern Fly, an invasive Hemipteran had been captured in Riverside Park on September 5th and she urged members to be on the lookout for this destructive pest. On a more positive note, a Virginia Rail and a Sora had been observed in Abingdon and Madison Square Parks respectively. The president also reminded members to pay their dues, thanked Irene Payne and Elise Boeger for generous donations of books, reminded young members that natural history magazines are available free on the stage and that all members should check with the website for updates for Society news. There is also a vacancy on the Editorial Committee.
President Saunders then introduced Thomas Gray, Director of Science at the Wildlife Alliance and a committee member of the IUCN Species Survival Commission. His talk, “Conserving Southeast Asia’s Elusive Rarities,” emphasized that conservationists must tackle the problem of conserving species that might be present but rarely seen. This is an acute problem in Southeast Asia, with its very high-density human population and its incredible species diversity. He pointed out that this area is a hotspot for species at risk, as monitored by the IUCN. As a researcher in the Cardamom Rain Forest of Cambodia, he has observed a dramatic increase in illegal logging and trapping of bush meat since the advent of China’s Belt and Road infrastructure initiative, with potentially devastating effects on the area’s wild life. To address the issue of where elusive species are to be found, Thomas described various methods, including the use of camera traps, interviewing local people about the wild animal food that they are eating, DNA sampling of bloodsucking species such as leeches and mosquitoes and even sampling of river water for ecological evidence of the DNA of specific species. These methods have helped to determine the ranges of rare species such as the chevrotain, the white-eared night heron, the extremely elusive Saola, and the spawning area of the Mekong Giant Catfish. The last is especially important, as a dam is being built between the upriver spawning grounds and the area in which the adults live. Such information may help to persuade governments to protect rare and endangered species, although as Thomas pointed, out enforcement is often lax or non-existent. This is where organizations such as the Wildlife Alliance can help by providing manpower and logistics.
The meeting adjourned at 8:35 pm.
Respectfully submitted by
Hamish Young, Recording Secretary