Vaux’s Swifts in Portland – 15 Years of Monitoring an Iconic Bird

For 15 year, Portland Audubon has counted migrating Vaux’s Swifts at Chapman Elementary School and other sites in the Portland region as part of a community science effort to monitor fall chimney roost site use, safeguard key roosting sites from disturbances, and educate the public on the protection of this species of concern. Data are contributed annually to a larger West Coast wide tracking effort. Vaux’s Swift population numbers have been declining for several decades, likely due primarily to habitat loss. This species historically utilized large hollowed out old-growth tree snags to roost. Now, many depend on large chimneys as they make their annual migration back and forth from their wintering grounds in the Neotropics to breeding areas in Northwestern North America. The Chapman chimney is one of the most important fall swift roosting sites on the entire West Coast and therefore is vital to protect. This chimney may host upwards of 160,000 swifts in a given season. During peak migration (mid-September) the chimney has hosted as many as 16,000 birds on a given night. The overall trend of use for this chimney over the 15-year period has remained stable, with an average of slightly over 5,000 swifts per night (Sept. 3-30). This effort has informed our work to educate the public to minimize disturbances to swifts - including by increasing recreational drone use. Along with the swift counts, our SwiftWatch program has provided educational outreach to tens of thousands of members of the public over the years connecting the importance of urban areas for birds and other wildlife

Bird Use of Northern Alaska Oilfield Rehabilitation Sites

Breeding bird response to habitat rehabilitation after anthropogenic disturbance has received little attention in the Arctic. The North Slope of Alaska is an important breeding ground for many populations of migratory birds and has also supported major oilfields since the late 1960s. The most obvious impacts of industrial development to nesting birds are direct habitat loss and fragmentation resulting from the construction of infrastructure, along with increased mechanical noise, vehicle traffic, and other forms of anthropogenic disturbance. In response to state and federal requirements, efforts have been made to rehabilitate abandoned portions of the oilfields. We compared bird use at rehabilitation sites and at nearby paired reference sites. Densities of shorebirds and passerines varied between rehabilitation sites and reference sites, but waterfowl densities did not. Specifically, passerine and shorebird densities were higher at reference sites in the early or mid-season and lower at reference sites in the late season. Additionally, birds on rehabilitation sites were primarily observed foraging and resting, while behavior observed on paired reference sites was more diverse and included courtship displays, nesting, and aggression. Further, rehabilitation sites supported significantly fewer nests and fewer species than recorded at reference sites. Our findings suggest that sites 3 to 10 years post rehabilitation do not provide bird habitat comparable to nearby reference sites and, by extension, do not provide shorebird and passerine habitat comparable to that found prior to development. However, rehabilitation sites appear to provide adequate habitat for waterfowl and are important to shorebirds and passerines as foraging areas. Continued monitoring will be needed to establish the long-term suitability of rehabilitation sites, compared to reference sites, as breeding habitat for birds.Dans l’Arctique, la réponse des oiseaux nicheurs à la remise en valeur de l’habitat après des perturbations d’origine anthropique a été peu étudiée. Le North Slope de l’Alaska est un lieu de reproduction important pour de nombreuses populations d’oiseaux migrateurs. Des champs pétroliers d’envergure y ont également été aménagés depuis la fin des années 1960. Les incidences les plus évidentes du développement industriel sur les oiseaux nicheurs sont la fragmentation et la perte directe d’habitat découlant de la construction d’infrastructures ainsi que l’augmentation du bruit mécanique, de la circulation de véhicules et d’autres formes de perturbations anthropiques. En raison des exigences de l’État et de l’administration fédérale, des efforts ont été déployés pour remettre en valeur les zones abandonnées des champs pétroliers. Nous avons comparé l’utilisation par les oiseaux des lieux remis en valeur à des lieux de référence jumelés des environs. Les densités d’oiseaux de rivage et de passereaux variaient dans les lieux remis en valeur et les lieux de référence, mais ce n’était pas le cas des densités de la sauvagine. Plus précisément, les densités de passereaux et d’oiseaux de rivage étaient plus élevées aux lieux de référence en début ou en milieu de saison, et moins élevées aux lieux de référence en fin de saison. De plus, les oiseaux de lieux remis en valeur ont surtout été vus en train de se nourrir ou de se reposer, tandis qu’aux lieux de référence, leurs comportements étaient plus variés et comprenaient des comportements de parade nuptiale, de nidification et d’agression. Par ailleurs, les lieux remis en valeur abritaient un beaucoup moins grand nombre de nids et moins d’espèces que les lieux de référence. Selon nos constatations, de trois à dix ans après les travaux de remise en valeur, ces lieux ne présentent pas, pour les oiseaux, un habitat comparable aux lieux de référence des environs et, par conséquent, ils ne fournissent pas aux passereaux et aux oiseaux de rivage un habitat comparable à celui qui s’y trouvait avant le développement industriel. Toutefois, les lieux remis en valeur semblent présenter un habitat adéquat pour la sauvagine et revêtent de l’importance comme lieux de ravitaillement pour les oiseaux de rivage et les passereaux. Une surveillance continue s’avère nécessaire afin d’établir la convenance à long terme des lieux remis en valeur, comparativement aux lieux de référence, comme habitat de nidification pour les oiseaux

Unexpected diversity in socially synchronized rhythms of shorebirds

The behavioural rhythms of organisms are thought to be under strong selection, influenced by the rhythmicity of the environment. Such behavioural rhythms are well studied in isolated individuals under laboratory conditions, but free-living individuals have to temporally synchronize their activities with those of others, including potential mates, competitors, prey and predators. Individuals can temporally segregate their daily activities (for example, prey avoiding predators, subordinates avoiding dominants) or synchronize their activities (for example, group foraging, communal defence, pairs reproducing or caring for offspring). The behavioural rhythms that emerge from such social synchronization and the underlying evolutionary and ecological drivers that shape them remain poorly understood. Here we investigate these rhythms in the context of biparental care, a particularly sensitive phase of social synchronization where pair members potentially compromise their individual rhythms. Using data from 729 nests of 91 populations of 32 biparentally incubating shorebird species, where parents synchronize to achieve continuous coverage of developing eggs, we report remarkable within-and between-species diversity in incubation rhythms. Between species, the median length of one parent's incubation bout varied from 1-19 h, whereas period length-the time in which a parent's probability to incubate cycles once between its highest and lowest value-varied from 6-43 h. The length of incubation bouts was unrelated to variables reflecting energetic demands, but species relying on crypsis (the ability to avoid detection by other animals) had longer incubation bouts than those that are readily visible or who actively protect their nest against predators. Rhythms entrainable to the 24-h light-dark cycle were less prevalent at high latitudes and absent in 18 species. Our results indicate that even under similar environmental conditions and despite 24-h environmental cues, social synchronization can generate far more diverse behavioural rhythms than expected from studies of individuals in captivity. The risk of predation, not the risk of starvation, may be a key factor underlying the diversity in these rhythms.</p

Unexpected diversity in socially synchronized rhythms of shorebirds

The behavioural rhythms of organisms are thought to be under strong selection, influenced by the rhythmicity of the environment1, 2, 3, 4. Such behavioural rhythms are well studied in isolated individuals under laboratory conditions1, 5, but free-living individuals have to temporally synchronize their activities with those of others, including potential mates, competitors, prey and predators6, 7, 8, 9, 10. Individuals can temporally segregate their daily activities (for example, prey avoiding predators, subordinates avoiding dominants) or synchronize their activities (for example, group foraging, communal defence, pairs reproducing or caring for offspring)6, 7, 8, 9, 11. The behavioural rhythms that emerge from such social synchronization and the underlying evolutionary and ecological drivers that shape them remain poorly understood5, 6, 7, 9. Here we investigate these rhythms in the context of biparental care, a particularly sensitive phase of social synchronization12 where pair members potentially compromise their individual rhythms. Using data from 729 nests of 91 populations of 32 biparentally incubating shorebird species, where parents synchronize to achieve continuous coverage of developing eggs, we report remarkable within- and between-species diversity in incubation rhythms. Between species, the median length of one parent’s incubation bout varied from 1–19 h, whereas period length—the time in which a parent’s probability to incubate cycles once between its highest and lowest value—varied from 6–43 h. The length of incubation bouts was unrelated to variables reflecting energetic demands, but species relying on crypsis (the ability to avoid detection by other animals) had longer incubation bouts than those that are readily visible or who actively protect their nest against predators. Rhythms entrainable to the 24-h light–dark cycle were less prevalent at high latitudes and absent in 18 species. Our results indicate that even under similar environmental conditions and despite 24-h environmental cues, social synchronization can generate far more diverse behavioural rhythms than expected from studies of individuals in captivity5, 6, 7, 9. The risk of predation, not the risk of starvation, may be a key factor underlying the diversity in these rhythms

Population Density of Free-Roaming Cats in Relation to Feeding Stations on Hayden Island

Free-roaming cats have a devastating impact on wildlife populations with stray/feral cats being the most problematic. In some areas, community members provide these cats with food, water, and shelter often in conjunction with a trap, neuter, return (TNR) program. Regardless of TNR, some studies suggest that feeding stray cats allows them to live longer which increases their impact on local wildlife populations. In contrast, we documented that a constantly available food source correlated to a higher density of cats in urban areas with less wildlife value and where they can be integrated into a TNR program. The Hayden Island Cat Project has utilized TNR, cat adoption, and outreach to humanely reduce the free-roaming cat population since 2014. Many residents on the island provide feeding stations for the cats and actively participate in the TNR program. To determine how feeding might affect cat spatial distribution, camera traps were placed at 20 different stations in urban and natural areas on Hayden island. Additional data from the annual road cat count was used to compare cat density relative to feeding stations utilizing ArcGIS. Coordinates of feeding stations based on a resident survey were overlaid onto the cat location coordinates and a clear density correlation appeared. Camera traps reinforced these findings whereby only a single cat was photographed in the natural area. These results demonstrate that feeding free-roaming cats combined with management actions aimed at humanely reducing cat populations, may lessen the impact on wildlife and be ethically acceptable to local residents

Density of Free-Roaming Cats Related to Feeding Stations on Hayden Island, Oregon

Free-roaming cats have a devastating impact on wildlife populations with stray/feral cats being the most problematic. In some areas, community members provide these cats with food, water, and shelter often in conjunction with a trap, neuter, return (TNR) program. Hayden Island located north of Portland, Oregon is home to a managed colony of feral and stray cats. Some island residents provide feeding stations for the cats and actively participate in population management. To determine how feeding stations might affect cat spatial distribution, camera traps were placed at 19 different stations in urban and natural areas on Hayden island. Additional annual road cat count data was used to compare cat density relative to feeding stations utilizing ArcGIS. When individual cat locations were overlapped with the heat map for feeding stations, greater cat densities in proximity to feeding stations were observed. These results were supported by a density analysis of cats and feeding stations as well as the camera trap results as only a single cat was photographed in the natural area. We documented that a reliable food source was connected to a higher density of cats in urban areas with less wildlife value and where they can be more easily monitored

Bird Response to Habitat Restoration at Fernhill Wetlands

In 2014-15 Clean Water Services implemented a massive habitat restoration project at Fernhill Wetlands in Forest Grove, Oregon that transformed 90 acres of unused sewage ponds into native wetland habitats designed to naturally treat wastewater. Since spring 2015 the Audubon Society of Portland (ASOP) has assessed bird response to this habitat restoration effort through a community science effort involving local birders, formal bird surveys conducted by ASOP, and analysis of historical eBird surveys conducted at the site for decades. Our general predictions were that 1) Overall avian species richness and abundance would increase, 2) Open-water dependent species would diminish in abundance, and 3) Species dependent on native wetland habitats would increase. Our key preliminary findings include: 1) Species richness was significantly higher post-restoration and is particularly accentuated during the summer season; 2) Overall species abundance does not appear to have changed significantly between pre- and post-restoration periods, however, at the individual species level we document significant shifts in abundance. Most of these shifts fit our a priori predictions. In general, most waterbird species (including Virginia Rail and Sora), wetland-dependent songbirds (including Red-winged Blackbird and Common Yellowthroat), and dabbling ducks (Mallard and Gadwall) have higher abundances post-restoration while wintering grebes and fall migratory shorebirds have lower abundances post-restoration, and 3) We provide evidence that community science eBird surveys and the formal transect surveys were directly comparable. Our findings demonstrate benefits to native bird communities that can be achieved through integration of green infrastructure strategies to manage wastewater

A study of avian population response after habitat restoration using remote sensing and community science bird observation data

During the last two centuries, the contiguous United States has lost over half of its wetland habitats. Preserving the remaining wetland habitats and reversing this trend is of critical importance. Fernhill Wetlands in Forest Grove, Oregon is a natural wastewater treatment site that was transformed from unused wastewater ponds to a complex natural wetland habitat in 2014-15. To assess the effect of habitat restoration on biodiversity changes, previous studies involved comparisons of bird populations before and after habitat restoration. In this study, Landsat-8 and Sentinel-2 satellite imagery and PRISM climate data were analyzed using Google Earth Engine to calculate vegetation, water and climate indices for Fernhill Wetlands for the first time for the pre- and post-restoration periods. Then, the summary data was fed into Microsoft Excel and R and quantitative correlations were established between these indices and community science bird observation data from the Cornell University eBird database collected using a protocol developed by Portland Audubon. The study showed the effects of the habitat restoration, both positive and negative, on several species. Shorebirds, marsh birds and others that lived at the water’s edge showed much subtler and sometimes unexpected reactions to the habitat change. Additionally, supervised machine learning classification was used to obtain clarity on land, vegetation and water changes in the region of interest. This study could be of great interest to the Fernhill Wetlands managers to help guide further habitat modifications

Portland Christmas Bird Count – An 80-year review of species trends (1938-2017)

Since 1915, Portland Audubon has organized the Portland Christmas Bird Count (CBC), recruiting community scientists to identify and count all bird species within a 15-mile-radius circle around Portland. Results are contributed annually to National Audubon’s database, which has provided critical information on the status of bird populations across the continent. We examine trends in bird numbers across 80 years (1938-2017) for 25 species using Portland CBC data. To conduct the CBC circle-level analysis we used statistical techniques originally developed by U.S. Geological Survey, Patuxent Wildlife Research Center, and National Audubon for region-wide population trends. Interpretation of findings at the scale of an individual CBC circle has limitations, as we can draw conclusions relevant only to the Portland CBC circle and only to the winter season. We control for effort but do not include other variables (e.g. temperature, changes in land-use, etc.) in the analysis. Of the species examined, 13 indicate an increasing trend, 10 a decreasing trend, and two remain stable. While these trends should be interpreted cautiously, they provide a window into Portland’s “avifauna past” and provide perspective on how winter bird communities have fared for nearly a century. These findings can help us understand how local and regional conservation efforts have played roles in benefiting some species and, at the same time, what challenges may be making it difficult for other species to survive in Portland’s dynamic landscape. This helps us to look ahead and more effectively plan conservation action for the future

Predicting Mesopredator Occupancy in the Portland Metropolitan Area

Mesopredators—medium-sized predators such as coyote (Canis latrans), common raccoon (Procyon lotor), and Virginia opossum (Didelphis virginiana)—are well established in cities and live closely with humans. However, we still know relatively little about these animals’ habitat selection and behavior as they navigate urban space. How do spatial attributes like the proximity to water or housing density affect where mesopredators choose to live? As part of an ongoing study, we are exploring the spatial occupancy of three mesopredator species as a function of land cover characteristics and sociodemographic factors in the Portland metropolitan area. In collaboration with the nationwide Urban Wildlife Information Network (UWIN), we established 25 monitoring sites along a trans-Portland transect extending 50 kilometers from Hillsboro to Gresham. Using motion-triggered camera traps active from spring 2019 to spring 2021 we collected occupancy results for three non-domestic mesopredator species: coyote (268 detections), common raccoon (218 detections), and Virginia opossum (406 detections). We used 40 landscape and sociodemographic attributes to characterize the habitat around each camera trap, allowing us to measure the influence of features such as human population density, road density, and household income on the presence of mesopredators. This presentation will provide an update on the Portland UWIN project and this specific study, emphasizing the application of this research in urban wildlife management and building habitat connectivity