The peregrine falcon (Falco peregrinus) population in eastern North America has grown significantly since the early 1980s, especially in urban areas, but few studies have assessed the factors that influence productivity. We reviewed all documented nesting attempts from southern Ontario, Quebec, Massachusetts, New Jersey, and Pennsylvania from 1980 through 2006 to evaluate these factors. Of 801 nesting attempts, 663 were successful, producing a total of 1,613 young. Mean productivity ranged from 1.7 young fledged per nesting attempt in New Jersey to 2.9 in Quebec. Peregrines nesting in quarries or on buildings had higher productivity than those using marsh towers or bridges, but productivity did not differ overall between urban and rural sites. Nests with overhead cover had higher productivity than those without, as did nests in trays or boxes compared to sites without any human‐provided nesting aids. Peregrines favored nest sites facing east to south, but productivity did not vary significantly with direction. Several adults have contributed disproportionately to the growth of the eastern population, with just 5 females and males accounting for 8% and 9% of all young fledged, respectively. Of 160 documented mortalities, we identified cause of death for 118, with the most common being collisions with buildings (36%), vehicles (9%), aircraft (8%), and power lines (8%). In many urban areas, grounded fledglings are rescued and returned to higher perches. Of 85 individuals from southern Ontario that were rescued, at least 8 have subsequently bred, producing 65 known offspring. Although peregrines have been thriving in eastern cities, continued management effort may be required for them to maintain their level of success, with key measures including provision of appropriately located nest boxes and rescue of grounded fledglings. © 2014 The Wildlife Society.
The North American Breeding Bird Survey, Christmas Bird Count, and regional and national conservation assessments provide convincing evidence that the short-eared owl (Asio flammeus) is experiencing a range-wide, long-term decline in abundance in North America. However, the species has received little conservation or research attention. The short-eared owl is vulnerable to decline because it relies heavily on large, intact grasslands and a specialized diet of unpredictable small mammal prey. The species' nomadic movements compound these vulnerabilities by making a decline difficult to detect with current monitoring programs while obfuscating stewardship responsibilities for managers. The primary threat to the species is loss, fragmentation, and degradation of large tracts of native grasslands and wetlands. We propose the following conservation priorities to better understand and begin addressing the short-eared owl's decline: 1) better define and protect important habitats; 2) improve population monitoring; 3) determine seasonal and annual movements; 4) re-evaluate NatureServe's short-eared owl national conservation classifications; 5) develop management plans and tools; and 6) classify raptors, including short-eared owls, as migratory birds in Canada. We contend that the short-eared owl's need for habitat conservation at large spatial scales, status as a predator, and high reproductive potential that affords the species capacity to recover, make it an effective and useful candidate as an umbrella species for grassland conservation. Ó 2014 The Wildlife Society.KEY WORDS Asio flammeus, conservation, decline, grassland, North America, research priorities, short-eared owl, status.Empirical evidence demonstrates a long-term, range-wide decline in short-eared owl (Asio flammeus) abundance in North America since at least 1966. Multiple lines of evidence at several spatial scales corroborate this species' decline,
Bird monitoring in North America over several decades has generated many open databases, housing millions of structured and semi‐structured bird observations. These provide the opportunity to estimate bird densities and population sizes, once variation in factors such as underlying field methods, timing, land cover, proximity to roads, and uneven spatial coverage are accounted for. To facilitate integration across databases, we introduce NA‐POPS: Point Count Offsets for Population Sizes of North American Landbirds. NA‐POPS is a large‐scale, multi‐agency project providing an open‐source database of detectability functions for all North American landbirds. These detectability functions allow the integration of data from across disparate survey methods using the QPAD approach, which considers the probability of detection (q) and availability (p) of birds in relation to area (a) and density (d). To date, NA‐POPS has compiled over 7.1 million data points spanning 292 projects from across North America, and produced detectability functions for 338 landbird species. Here, we describe the methods used to curate these data and generate these detectability functions, as well as the open‐access nature of the resulting database.
Determination of a bird’s age or cohort is critical for studies on avian demography, occurrence patterns, behavior, and conservation management. Age designations have largely been developed in north-temperate regions and utilize calendar-based or seasonally based codes; however, in tropical regions and in the southern hemisphere, these coding systems have limited utility at best. To address these issues, we had previously devised the “WRP system,” based on the nomenclature of Humphrey and Parkes (H–P) and Howell et al., which defines molts in an evolutionary context applicable to birds globally. Here we refine and build upon core concepts and definitions of the WRP coding system, resolving key limitations that were identified during its first decade of use. The WRP system employs a three-letter alpha code in which each letter describes a different aspect of H–P terminology: the molt cycle (which informs a bird’s age) and molt and plumage status within the cycle (each of which can also inform age). Here we recommend the continued use of most of the original (“core”) WRP coding while augmenting the system with an optional adjunct-code entry for comprehensiveness, clarity, and flexibility, and we clarify a few additional codes to cover less common molting and plumage strategies. For most users, from 7 to 13 core and 1 adjunct WRP code will be sufficient to describe all plumages and provide molt status and ages for demographic studies or other purposes. The revised WRP system is flexible enough to be adapted to the specific goals of programs while also providing core codes that can facilitate the comparison of avian age, molt, and plumage status on a global basis. We anticipate that our revised and standardized version of the WRP system will be easily adopted and could eventually replace calendar-based and seasonally based coding.
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