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Haliaeetus leucocephalus (Bald Eagle) is a species that congregates in communal roosting sites during the non-breeding periods of its life cycle. Wildlife agencies are directed to protect roosts, but their nocturnal usage and remote locations make them challenging to identify and monitor. We remotely identified and ground-truthed roost sites using satellite telemetry data. We delineated 13 confirmed roosts and another 34 suspected roosts. Volunteers observed 12 roosts with ground surveys and confirmed 92% were in use by eagles during their first observation. These results suggest use of eagle-tracking data to remotely identify communal roosts is a promising tool for finding and protecting eagle roosting habitat. This method can be complemented with volunteer surveys to confirm ongoing roost use.
We monitored the reproduction, dispersal, and regeneration of a wild population of Castanea dentata (American Chestnut), established from 4 seed-bearing trees planted in a western Maine forest in 1982. The 40-year-old parent trees, sourced from wild stock of a relict population in northern Michigan, show no obvious signs of blight and have been producing viable seeds now for >20 years. Over the course of 2 surveys conducted in 2019 and 2020, we mapped and measured 1348 offspring, varying in size from seedlings to nearly mature trees. As of October 2020, the natural spread of this population had expanded to at least 370 m from the parent trees, with an average dispersal distance of 124 m. While previous publications have focused on the scatter-hoarding behavior that gave rise to this expanding wild population, we report on possible factors affecting their spread, their fate, and prognosis for the future. Given the absence of other reproductive populations of American Chestnut in the immediate vicinity, our data provide rare insights into natural seed dispersal from a known point of origin while documenting the return of a functionally extinct species to a northern hardwood forest ecosystem.
Many experimental aquatic ecologists are familiar with the commonly used model system Sarracenia purpurea (Purple Pitcher Plant), as this plant contains an entire aquatic ecosystem with obligate invertebrates in its pitcher-shaped leaves. An obligate herbivore of the Purple Pitcher Plant, Exyra fax (Pitcher Mining Moth), consumes plant tissue and chews a hole at the base of the pitcher, draining the pitcher of fluid and thereby creating unsuitable habitat for obligate aquatic invertebrates. Historically, it has been noted that the obligate aquatic invertebrate larvae within the Purple Pitcher Plant are incapable of leaving the pitcher they were initially deposited in as eggs. The objective of this experiment was to determine if larvae of the obligate invertebrate Metriocnemus knabi (Pitcher Plant Midge) is capable of emigrating to new pitchers when faced with pitcher drainage as a result of damage from the Pitcher Mining Moth. We placed midge larvae of varying abundances in experimental pitchers that were drained in a way similar to the work of Pitcher Mining Moth larvae. After drainage, larval midges were allowed 2 weeks to emigrate. At the end of 2 weeks, as much as 38.2% of the initial abundance of M. knabi larvae had emigrated out of drained pitchers to new, viable, fluid-filled pitchers and survived. We present here the first evidence that the obligate Pitcher Plant Midge larvae are capable of emigration when faced with unsuitable habitat.
Many studies of rodents rely on the use of live trapping. Comparative studies of trap type provide researchers with information that can inform their trapping design, yet relatively few comparative studies include economical mesh traps, such as Fitch traps. I compared the effectivess of Sherman box traps and Fitch mesh traps for rodent sampling in a grassland ecosystem. Between 2016 and 2017, I set 120 trap stations with both Fitch and Sherman traps for a total of 6000 trap nights at a single tallgrass prairie-restoration site in northern Illinois. I compared trap effectivess overall and for each species captured. Fitch traps were significantly better at capturing ground squirrels than Sherman traps and comparable to Sherman traps at capturing voles and jumping mice. These results demonstrate Fitch traps provide a viable alternative to Sherman traps for sampling at this location and indicate they should be considered in future comparative studies to further assess their effectiveness, especially in grasslands.
We examined patterns of avian diversity in a maritime ecosystem at Orient Beach State Park on the North Fork of Long Island, NY. We compared avian diversity in beach, saltmarsh, shrub, a Juniperus virginiana (Eastern Redcedar) maritime forest, and an interior hardwood forest at nearby Mashomack Preserve. Maritime forest was highest in bird species richness followed by saltmarsh, interior forest, shrub, and beach. Habitat variables best explaining avian species richness were sand cover, vegetation cover, visibility, and height of nearest vegetation. The peninsular shape of the maritime forest supported greater edge habitat compared to the interior forest, encouraging greater avian diversity. This study provides baseline information for the conservation of a rare maritime ecosystem.
We sampled the vertebrate community of a 20-ha conservation easement in Venango County, PA, from April through August 2021. The restoration and management efforts on this easement were designed to improve the meadow habitat for one of the few remaining populations of Sistrurus catenatus (Eastern Massasauga Rattlesnake) in Pennsylvania, and our sampling efforts were focused on evaluating the potential prey base available to the rattlesnakes at this site. We identified 9 amphibian species, 10 reptile species, and 11 small mammal species. For amphibians, Anaxyrus americanus (American Toad) was the most abundant species, accounting for 32.6% of the total, followed by Notophthalmus viridescens (Red-Spotted Newt) with 30.6% of total abundance. Thamnophis brachystoma (Short-Headed Gartersnake) comprised more than half (53.7%) of all reptiles sampled, followed by Thamnophis sirtalis (Eastern Gartersnake; 22.7%). Peromyscus leucopus (White-Footed Mouse) was the most abundant mammal species, accounting for 37.4% of all mammals surveyed, followed by Microtus pennsylvanicus (Eastern Meadow Vole; 24.8%). Mammals had the greatest species richness (S = 11), while reptiles had the greatest total abundance (TA = 361), and amphibians had the greatest species evenness (E = 0.799). Species accounts for Venango County indicate that we sampled 40.9% (9/22), 37.0% (10/27), and 21.2% (11/52) of the known amphibian, reptilian, and mammalian species, respectively, within this restored meadow habitat. Our results suggest that the restoration efforts on this easement study site have been extremely effective in creating meadow habitat that supports a diversity of prey species for the Eastern Massasauga Rattlesnake.
Populations of freshwater gastropods are decreasing globally. To investigate one aspect of decline, we exposed the benthic dwelling hermaphroditic snail Planorbella (= Helisoma) trivolvis (Say) (Marsh Rams-horn) to polychlorinated biphenyls (PCBs). Marsh Rams-horn is a simultaneous hermaphrodite, suggesting that disruption of reproductive success is independent of snail interaction and more dependent on internal controls. We examined the impact of exposure to PCBs on mortality, reproductive success, and tissue hormone concentrations. Exposure to Aroclor®1254 in concentrations found in natural habitats caused higher mortality and reduced reproductive success. Additionally, tissue estrogens were significantly elevated while testosterone remined unchanged in PCB-exposed snails. Given the importance of hermaphroditic freshwater gastropods in ecosystems, worldwide population decline, and ubiquity of PCBs, identifying the impact of exposure informs our ability to combat population loss.
In June 2020, we monitored a nest in Southampton, MA, that contained 2 Dumetella carolinensis (Gray Catbird) and 3 Turdus migratorius (American Robin) eggs. Females of both species alternately incubated the mixed clutch, and 2 catbird and 2 robin young successfully hatched and fledged from the nest. Adults of both species provided both intra- and interspecific parental care (e.g., nestling provisioning, brooding, and nest sanitation). The catbirds, in particular, often did not preferentially provision their own young. In fact, following earlier fledging of the catbird young, an adult catbird continued to visit the nest to care for the robin nestlings, including fecal sac removal on at least 2 occasions. After the 2 robin young fledged, we did not observe any crossover post-fledging care. Our study represents the most detailed and protracted account among the very few documented cases of nest sharing between these species.
I observed mobbing of Glaucomys volans (Southern Flying Squirrel), upon removal and release from nesting boxes designed for them, by various bird species (1–9 total individual birds) on 33 occasions during winter surveys for the squirrels in southeast Ohio. I observed instances of mobbing by 1–3 species of primary and/or secondary cavity-nesting songbirds and woodpeckers. Mobbing behavior included flights within 1–2 m of a flying squirrel briefly positioned on a tree trunk as well as vocalizations. Mobbing episodes lasted 5–180 seconds, which largely depended on the amount of time a flying squirrel remained visible before retreating into a natural cavity. In light of the mobbing response reported here, perhaps more consideration should be given to the potential impacts that Southern Flying Squirrels may have on bird communities.
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