scholarly journals Long-Term Modelling Reveals Contrasting Population Trends Among North American Hummingbirds

2021 ◽  
Author(s):  
Simon G. English ◽  
Christine A. Bishop ◽  
Scott Wilson ◽  
Adam C. Smith
Keyword(s):  
North America ◽  
North American ◽  
Conservation Status ◽  
Critical Role ◽  
Population Trends ◽  
Ecological Communities ◽  
Breeding Bird ◽  
Past Half Century ◽  
Rate Of Decline

Abstract As pollinators, hummingbirds play a critical role for both the function of ecological communities and in providing ecosystem services for people. Throughout North America, this diverse family of birds is experiencing impacts of transformations to their habitat. To examine the conservation status of North American hummingbirds, we analyzed Breeding Bird Survey data for 8 species and 3 genera from 1970 to 2019 (long-term) and from 2009 to 2019 (short-term, approximately three generations). Among the Selasphorus genus, Allen’s, rufous, and broad-tailed hummingbirds have declined since 1970, and the rate of decline increased from 2009 to 2019. In a reversal of the trends from the past half-century, ruby-throated hummingbirds of Eastern North America have declined since approximately 2004 throughout most of the species range. In contrast, Anna’s hummingbird populations have increased dramatically since 1970 in their range in western North America. This increase is most exaggerated in Canada, related to a northern range expansion. Our results highlight contrasting population trends across species and provide an important first step to address declines, most notably among species in the Selasphorus and Archilochus genera. Our geographic modelling also emphasizes the need to prioritize regions of conservation interest in the breeding and wintering ranges of hummingbirds.

scholarly journals Current contrasting population trends among North American hummingbirds

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Simon G. English ◽  
Christine A. Bishop ◽  
Scott Wilson ◽  
Adam C. Smith
Keyword(s):  
North America ◽  
North American ◽  
Conservation Status ◽  
Critical Role ◽  
Ecological Communities ◽  
Breeding Bird ◽  
Past Half Century ◽  
Bird Survey ◽  
Rate Of Decline

AbstractAs pollinators, hummingbirds play a critical role for both the function of ecological communities and in providing ecosystem services for people. To examine the conservation status of North American hummingbirds, we analyzed Breeding Bird Survey data for 8 species and 3 genera from 1970 to 2019 (long-term) and from 2009 to 2019 (short-term, approximately three generations). Among the Selasphorus genus, Allen’s, rufous, and broad-tailed hummingbirds have declined since 1970, and the rate of decline increased from 2009 to 2019. Contrasting the trends from the past half-century, ruby-throated hummingbirds of Eastern North America have declined since approximately 2004 throughout most of the species’ breeding range. In contrast, Anna’s hummingbird populations have increased dramatically since 1970 in their range in western North America. We also tested whether apparent declines might be due to a growing mismatch between the timing of breeding and the timing of BBS surveys. We found no evidence for such an effect, thus supporting the hypothesis that trends reflect true demographic change. Our analyses and geographic modelling highlight the urgent need of regulatory action to conserve hummingbirds uniquely capable of filling their niche in North America.

scholarly journals Long-Term Declines and Decadal Patterns in Population Trends of Songbirds in Western North America, 1979–1999

The Condor ◽  
2003 ◽  
Vol 105 (4) ◽  
pp. 737-755 ◽  
Author(s):  
Grant Ballard ◽  
Geoffrey R. Geupel ◽  
Nadav Nur ◽  
Thomas Gardali
Keyword(s):  
Life History ◽  
North America ◽  
Large Scale ◽  
Population Trends ◽  
Significant Heterogeneity ◽  
Long Distance ◽  
Breeding Bird ◽  
Historia De Vida ◽  
Los Grupos

Abstract We analyzed population trends from a constant-effort mist-netting study conducted in central coastal California during the autumns of 1979–1999. Of 31 taxa captured in sufficient numbers, 16 underwent statistically significant declines and none increased. Twice as many species declined from 1989–1999 as compared to 1979–1989. Overall, our results were similar to those of regional Breeding Bird Surveys determined for the same species during the same period. In an attempt to identify possible causes for trends, we grouped species by various life-history categories including nest height, nest type, likelihood of cowbird parasitism, wintering location, winter food preference, and tolerance for human presence on the breeding grounds. All groups underwent significant declines, although high nesters, common cowbird hosts, and Neotropical migrants declined faster than their respective counterparts. While life-history attributes explained differences in trends between groups, there was significant heterogeneity of trends within groups. Capture rates of certain species and groups appeared to be affected by various climate variables, and accelerating declines since 1990 may reflect effects of large-scale climate cycles, particularly on long-distance migrants. We suggest that long-term population trajectories of songbird populations across North America may be better understood in the context of the Pacific Decadal Oscillation. Interpretation of our results is, in some cases, problematic due to the complex interaction of methodological limitations and environmental variables, especially habitat change on the study site. We recommend the use of multiple methods and multiple sites for monitoring trends in songbird population abundance during fall migration. Disminuciones a Largo Plazo y Patrones Década a Década en Tendencias Poblacionales de Aves Canoras en el Oeste de Norte América, 1979–1999 Resumen. Analizamos las tendencias poblacionales de un estudio de esfuerzo constante con redes de niebla realizado en la costa central de California durante los otoños de 1979 a 1999. De las 31 especies capturadas en números suficientes, 16 sufrieron disminuciones estadísticamente significativas y ninguna aumentó. En comparación con el período de 1979 a 1989, el doble de las especies disminuyeron entre 1989 y 1999. En general, nuestros resultados fueron similares a los determinados para las mismas especies en el mismo período por los censos regionales de aves reproductivas. En un intento por identificar las posibles causas de las tendencias, agrupamos las especies de acuerdo a varias categorías de historias de vida incluyendo altura del nido, tipo de nido, probabilidad de parasitismo por Molothrus, localidad de invernada, preferencias alimenticias en el invierno y tolerancia ante la presencia humana en las áreas reproductivas. Todos los grupos sufrieron disminuciones significativas, aunque las aves con nidos altos, los hospederos comunes de Molothrus y los migrantes neotropicales disminuyeron más rápidamente que sus respectivas contrapartes. Aunque los atributos de historia de vida explicaron las diferencias de las tendencias entre grupos, existió una heterogeneidad significativa al interior de los grupos. Las tasas de captura de ciertas especies y grupos parecieron ser afectadas por varias variables climáticas, y las disminuciones aceleradas desde 1990 podrían reflejar efectos de ciclos climáticos a gran escala, particularmente en migrantes de larga distancia. Sugerimos que las tendencias poblacionales a largo plazo de las aves canoras a través de Norte América podrían ser mejor entendidas en el contexto de la oscilación década a década del Pacífico. En algunos casos, la interpretación de nuestros resultados es problemática debido a la compleja interacción entre las limitaciones metodológicas y las variables ambientales, especialmente los cambios en el hábitat en el sitio de estudio. Recomendamos el uso de múltiples métodos y sitios para monitorear las tendencias en la abundancia de las poblaciones de aves canoras durante la migración de otoño.

scholarly journals Long-eared Owls, Asio otus: A Review of North American Banding

2005 ◽  
Vol 119 (3) ◽  
pp. 395 ◽  
Author(s):  
C. Stuart Houston
Keyword(s):  
North America ◽  
North American ◽  
Population Decline ◽  
Species Range ◽  
Population Trends ◽  
Northern Edge

In Saskatchewan, at the northern edge of the species’ range, the Long-eared Owl (Asio otus) is an irruptive species that has appeared in numbers during major vole (Microtus) outbreaks in 4 of 44 years. Seven other years have had either no bandings or no sightings over large areas. In a search for possible evidence of food-based nomadism, population trends, length and synchronicity of cycles, and longevity, I reviewed all banding in North America through 1998. Prior to banding office computerization (retroactive to 1955), 803 Long-eared Owls had been banded with 33 band encounters (4.1%). Between 1955 and 1998 there were another 10,250 banded by 426 banders with 86 band encounters (0.8%). Encounter records, especially those involving unexpected directions and distances, tend to support but do not prove food-based nomadism. Peaks of migration movements at different long-term stations occurred in different years. There is soft evidence of both 10- and 3-yr cycles. There is inconclusive evidence for a continuing population decline. The oldest banded bird in North America lived for 11 years, 1 month, but another possibly lived for 15 years, 8 months.

Sophistry, Security, and Socio-Political Structures in the American Revolution; or, Why Jamaica did not Rebel

1986 ◽  
Vol 29 (2) ◽  
pp. 319-344 ◽  
Author(s):  
T. R. Clayton
Keyword(s):  
North America ◽  
British Empire ◽  
American Revolution ◽  
North American ◽  
Western Hemisphere ◽  
American Colonies ◽  
Constitutional Principle ◽  
Mother Country ◽  
Political Structures

Britain's most important American colonies did not rebel in 1776. Thirteen provinces did declare their independence; but no fewer than nineteen colonies in the western hemisphere remained loyal to the mother country. Massachusetts and Virginia may have led the American revolution, but they had never been the leading colonies of the British empire. From the imperial standpoint, the significance of any of the thirteen provinces which rebelled was pale in comparison with that of Jamaica or Barbados. In the century before 1763 the recalcitrance of these two colonies had been more notorious than that of any mainland province and had actually inspired many of the imperial policies cited as long-term grievances by North American patriots in 1774. Real Whig ideology, which some historians have seen as the key to understanding the American revolution, was equally understood by Caribbean elites who, like the continental, had often proved extremely sensitive on questions of constitutional principle. Attacks of ‘frenzied rhetoric’ broke out in Jamaica in 1766 and Barbados in 1776. But these had nothing whatsoever to do with the Stamp Act or events in North America.

scholarly journals A Surface Wind Extremes (“Wind Lulls” and “Wind Blows”) Climatology for Central North America and Adjoining Oceans (1979–2012)

2015 ◽  
Vol 54 (3) ◽  
pp. 643-657 ◽  
Author(s):  
Jonny W. Malloy ◽  
Daniel S. Krahenbuhl ◽  
Chad E. Bush ◽  
Robert C. Balling ◽  
Michael M. Santoro ◽  
...  
Keyword(s):  
United States ◽  
North America ◽  
North American ◽  
North Atlantic Ocean ◽  
Grid Point ◽  
Surface Wind ◽  
Wind Speeds ◽  
The North ◽  
Anomalous Wind

AbstractThis study explores long-term deviations from wind averages, specifically near the surface across central North America and adjoining oceans (25°–50°N, 60°–130°W) for 1979–2012 (408 months) by utilizing the North American Regional Reanalysis 10-m wind climate datasets. Regions where periods of anomalous wind speeds were observed (i.e., 1 standard deviation below/above both the long-term mean annual and mean monthly wind speeds at each grid point) were identified. These two climatic extremes were classified as wind lulls (WLs; below) or wind blows (WBs; above). Major findings for the North American study domain indicate that 1) mean annual wind speeds range from 1–3 m s−1 (Intermountain West) to over 7 m s−1 (offshore the East and West Coasts), 2) mean durations for WLs and WBs are high for much of the southeastern United States and for the open waters of the North Atlantic Ocean, respectively, 3) the longest WL/WB episodes for the majority of locations have historically not exceeded 5 months, 4) WLs and WBs are most common during June and October, respectively, for the upper Midwest, 5) WLs are least frequent over the southwestern United States during the North American monsoon, and 6) no significant anomalous wind trends exist over land or sea.

scholarly journals New Population of the Rare Dragonfly Ophiogomphus howei (Odonata: Gomphidae) in Southern Michigan, United States

2020 ◽  
Vol 20 (5) ◽  
Author(s):  
Julie A Craves ◽  
Darrin S O’Brien ◽  
David A Marvin
Keyword(s):  
United States ◽  
North America ◽  
North American ◽  
Conservation Status ◽  
Urban Watershed ◽  
High Quality ◽  
Global Conservation ◽  
New Location

Abstract Ophiogomphus howei Bromley is a rare North American dragonfly, given a global conservation rank of Vulnerable by NatureServe. This species inhabits localized stretches of a limited number of typically undisturbed, high-quality, forested rivers in two disjunct regions in North America. We describe a new population in between the known ranges from an impaired river in a largely urban watershed in southern Michigan, United States. We also report a previously overlooked specimen from a new location in Pennsylvania, United States, and provide current occurrence and conservation status of the species in North America.

scholarly journals Long-term population trends of Sooty Terns Onychoprion fuscatus: implications for conservation status

2017 ◽  
Vol 59 (3) ◽  
pp. 213-224 ◽  
Author(s):  
B. John Hughes ◽  
Graham R. Martin ◽  
Anthony D. Giles ◽  
S. James Reynolds
Keyword(s):  
Conservation Status ◽  
Population Trends ◽  
Onychoprion Fuscatus

scholarly journals Estimating Population Trends With a Linear Model: Technical Comments

The Condor ◽  
2004 ◽  
Vol 106 (2) ◽  
pp. 435-440 ◽  
Author(s):  
John R. Sauer ◽  
William A. Link ◽  
J. Andrew Royle
Keyword(s):  
North American ◽  
Population Change ◽  
Survey Design ◽  
Population Trends ◽  
Breeding Bird Survey ◽  
Breeding Bird ◽  
The North ◽  
Bird Survey ◽  
Substantial Bias ◽  
Modelo Lineal

Abstract Controversy has sometimes arisen over whether there is a need to accommodate the limitations of survey design in estimating population change from the count data collected in bird surveys. Analyses of surveys such as the North American Breeding Bird Survey (BBS) can be quite complex; it is natural to ask if the complexity is necessary, or whether the statisticians have run amok. Bart et al. (2003) propose a very simple analysis involving nothing more complicated than simple linear regression, and contrast their approach with model-based procedures. We review the assumptions implicit to their proposed method, and document that these assumptions are unlikely to be valid for surveys such as the BBS. One fundamental limitation of a purely design-based approach is the absence of controls for factors that influence detection of birds at survey sites. We show that failure to model observer effects in survey data leads to substantial bias in estimation of population trends from BBS data for the 20 species that Bart et al. (2003) used as the basis of their simulations. Finally, we note that the simulations presented in Bart et al. (2003) do not provide a useful evaluation of their proposed method, nor do they provide a valid comparison to the estimating- equations alternative they consider. Estimando Tendencias Poblacionales con un Modelo Lineal: Comentarios Técnicos Resumen. A veces ha surgido controversia sobre la necesidad de considerar las limitantes del diseño de muestreo al estimar cambios poblacionales a partir de datos de conteos de aves. Los análisis de muestreos como el Muestreo de Aves Reproductivas de América del Norte (North American Breeding Bird Survey [BBS]) pueden ser bastante complejos; es natural preguntarse si esta complejidad es necesaria, o si los aná lisis estadísticos son desmedidos. Bart et al. (2003) proponen un análisis muy simple que sólo involucra regresión lineal simple, y contrastan su enfoque con los procedimientos basados en modelos. Nosotros revisamos los supuestos implícitos en el método que ellos proponen y documentamos que estos supuestos no son probablemente válidos para muestreos tales como el BBS. Una limitante fundamental de un enfoque basado exclusivamente en el diseño es la ausencia de controles para factores que influencian la detección de aves en los sitios de muestreo. Mostramos que el hecho de no modelar los efectos del observador en los datos de muestreo lleva a sesgos substanciales en las estimaciones de las tendencias poblacionales de las 20 especies que Bart et al. (2003) usaron como la base de sus simulaciones a partir de datos del BBS. Finalmente, notamos que las simulaciones presentadas en Bart et al. (2003) no brindan una evaluación útil del método que proponen ni tampoco ofrecen una comparación vá lida para la alternativa de estimación de ecuaciones que ellos consideran.

scholarly journals Range expansion of the vulnerable crayfish Creaserinus fodiens (Cottle, 1863) (Decapoda, Cambaridae) in Ontario, Canada, with added notes on the distribution, ecology and conservation status of this species in North America

Crustaceana ◽  
2021 ◽  
Vol 94 (4) ◽  
pp. 467-486
Author(s):  
Radu C. Guiaşu
Keyword(s):  
North America ◽  
Range Expansion ◽  
New Records ◽  
Conservation Status ◽  
Field Studies ◽  
Royal Ontario Museum ◽  
New Locations ◽  
Provincial Park ◽  
Crayfish Species

Abstract The distribution of the semi-terrestrial burrowing crayfish Creaserinus fodiens (Cottle, 1863) in Ontario was updated based on the examination of the records stored in the crayfish database of the Royal Ontario Museum in Toronto and specimens collected during field studies. New Ontario locality records are reported for this crayfish species from MacGregor Point Provincial Park and other nearby sites in Bruce County, along the shores of Lake Huron. These are among the northernmost locality records reported for this species in North America. These new records represent a northwestern range expansion for this crayfish species in southern Ontario. As a result of these new records, the revised distribution of this species in Ontario is estimated to cover an area of about 32 620 km2. This is an increase of 7620 km2 over a previous 1996 estimate of this range. Creaserinus fodiens is a vulnerable species in Ontario, mainly due to the loss of suitable wetland habitats. Thus, the new locations and the range expansion reported here provide some hopeful news about the long-term future of burrowing crayfishes in this Canadian province. At some of the new locations, C. fodiens was found together with Faxonius immunis (Hagen, 1870), another burrowing crayfish species. However, this analysis of all the relevant records found in the collections of the Royal Ontario Museum (Toronto) and the Canadian Museum of Nature (Ottawa) shows that our knowledge of the distribution of C. fodiens in Ontario remains quite incomplete. A survey of the conservation status and challenges for this crayfish species in various regions of North America was also undertaken.

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