Habitat openness and edge avoidance predict Saltmarsh Sparrow abundance better than habitat area

Abstract The Saltmarsh Sparrow (Ammospiza caudacuta) is a tidal marsh bird facing rapid population decline throughout its range, largely caused by degradation and loss of breeding habitat. Thus, there is a need to preserve tidal marshes in the northeastern United States, but to do so requires an understanding of the habitat features that support robust populations. Previous studies have shown Saltmarsh Sparrow abundance increases with marsh size, but in similar bird species, area sensitivity is more directly linked to edge avoidance. Whether additional landscape features affect the abundance of Saltmarsh Sparrows is unknown. We explored how the height of objects on the horizon, an index of habitat openness, affected the abundance of Saltmarsh Sparrows. Our primary goal was to determine whether the angle to the highest point on the horizon (“angle to maximum horizon”) predicted abundance better than marsh area or distance to the marsh edge. We used N-mixture models to evaluate the combination of spatial factors that best predicted Saltmarsh Sparrow abundance while also accounting for survey-level variables that could influence detection probability. We found that the interaction between distance to edge and angle to maximum horizon best predicted abundance. Taller objects on the horizon were negatively correlated with bird abundance, and this effect was strongest within 50 m of the marsh edge. When we considered the predictive powers of patch area, distance to edge, and angle to maximum horizon individually, angle to maximum horizon was the best single predictor. We found the highest abundance of Saltmarsh Sparrows at point locations where the angle to maximum horizon was 0.0°, and at angles greater than 12° the predicted abundance fell below 1 bird per survey point. We propose that managers should prioritize marsh openness and experimentally test the effect of marsh edge manipulations when making conservation decisions for this rapidly declining species.

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Movements of Radio-Marked California Ridgway's Rails During Monitoring Surveys: Implications for Population Monitoring

Journal of Fish and Wildlife Management ◽

10.3996/092014-jfwm-069 ◽

2015 ◽

Vol 6 (1) ◽

pp. 227-237 ◽

Cited By ~ 6

Author(s):

Thuy-Vy D. Bui ◽

John Y. Takekawa ◽

Cory T. Overton ◽

Emily R. Schultz ◽

Joshua M. Hull ◽

...

Keyword(s):

San Francisco ◽

Bird Species ◽

Population Monitoring ◽

Tidal Marshes ◽

Population Abundance ◽

Population Declines ◽

Directional Bias ◽

Marsh Bird ◽

Bird Monitoring ◽

Count Surveys

Abstract The California Ridgway's rail Rallus obsoletus obsoletus (hereafter California rail) is a secretive marsh bird endemic to tidal marshes in the San Francisco Bay (hereafter bay) of California. The California rail has undergone significant range contraction and population declines due to a variety of factors, including predation and the degradation and loss of habitat. Call-count surveys, which include call playbacks, based on the standardized North American marsh bird monitoring protocol have been conducted throughout the bay since 2005 to monitor population size and distribution of the California rail. However, call-count surveys are difficult to evaluate for efficacy or accuracy. To measure the accuracy of call-count surveys and investigate whether radio-marked California rails moved in response to call-count surveys, we compared locations of radio-marked California rails collected at frequent intervals (15 min) to California rail detections recorded during call-count surveys conducted over the same time periods. Overall, 60% of radio-marked California rails within 200 m of observers were not detected during call-count surveys. Movements of radio-marked California rails showed no directional bias (P = 0.92) irrespective of whether or not playbacks of five marsh bird species (including the California rail) were broadcast from listening stations. Our findings suggest that playbacks of rail vocalizations do not consistently influence California rail movements during surveys. However, call-count surveys may underestimate California rail presence; therefore, caution should be used when relating raw numbers of call-count detections to population abundance.

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Efecto de la estacionalidad y lluvias en la avifauna del Chaco Serrano Austral, Argentina

Revista de Biología Tropical ◽

10.15517/rbt.v65i3.29434 ◽

2017 ◽

Vol 65 (3) ◽

pp. 953

Author(s):

Gustavo Alfredo Fava ◽

Juan Carlos Acosta ◽

Graciela Mirta Blanco

Keyword(s):

Bird Species ◽

Reproductive Activity ◽

Breeding Habitat ◽

Bird Abundance ◽

Group Management ◽

Natural Park ◽

Chaco Serrano ◽

Site Survey ◽

Migrant Bird ◽

Resident Bird

In subtropical regions like the Chaco Serrano (33° S), rainfall has a marked seasonality, and water flood, caused by heavy rains, may have important consequences for dependent ecosystems. Conversely, the high pressure on available resources during dry periods can also affect the fauna diversity and distribution. Even though birds have shown to be excellent ecological indicators of these shifts in the environment, currently little is known about the avifauna of the Argentine Chaco Serrano phytogeographic district. Our aim was to study the resident bird population status in the Southern Chaco Serrano, its fluctuations in richness and abundance, and its relationship to seasonal variations, in monthly and annual hydroperiods. In order to assess the resident bird status over a two year period (2011 Mar.-2013 Feb.) we carried out 18 sampling surveys during pre-breeding (spring), breeding (summer) and non breeding periods (autumn-winter), in the Northeastern part of the Valle Fértil Natural Park, San Juan province, Argentina. During each site survey, we recorded bird assemblages found in six transects, and obtained bird abundance and species diversity. A mixed general linear model was employed to evaluate relationships between the studied variables. We found a total of 98 species of birds belonging to 33 families (44 resident species, 23 spring visitors, six summer visitors, two winter visitors and 23 with scarce registers). We also registered 68 of these species in both hydroperiods, 28 only during rainy periods and only two during the dry period. Both richness and abundance showed the highest values during the pre-breeding and rainy seasons, while different tendencies were detected during the isolated monthly rainfalls. These changes in bird densities were associated with the arrival of migratory species, mainly spring visitors, and probably in relationship with their reproductive activity, and to seasonal fluctuations in food resources. The Southern Chaco Serrano is a subtropical semiarid place that seems to be an important breeding habitat for many migrant bird species, which in turn promoted seasonal changes in species density and diversity, mainly during rainy years. This work contributed to our understanding on the causes of richness and abundance variations on birds, and will contribute to this important group management and conservation in this area.

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Early seral hardwood vegetation increases adult and fledgling bird abundance in Douglas-fir plantations of the Oregon Coast Range, USA

Canadian Journal of Forest Research ◽

10.1139/x2012-035 ◽

2012 ◽

Vol 42 (5) ◽

pp. 918-933 ◽

Cited By ~ 6

Author(s):

Tana M. Ellis ◽

Andrew J. Kroll ◽

Matthew G. Betts

Keyword(s):

Forest Management ◽

Pacific Northwest ◽

Management Practices ◽

Bird Species ◽

Relative Magnitude ◽

Breeding Habitat ◽

Population Declines ◽

Private Lands ◽

Bird Abundance ◽

Catharus Ustulatus

Recent evidence suggests that population declines of bird species associated with early-successional forest conditions may be associated with reduced quality of breeding habitat. Increasing intensity of forest management on private lands and decreased harvest rates on federal lands in the Pacific Northwest, USA, have resulted in a loss of diverse young forest stands, typically called early seral forest. Previous studies suggest that the amount of early seral broadleaf cover within conifer forests is linked to the composition of foliage-gleaning bird communities. However, information regarding productivity and juvenile use of post-breeding habitat in highly modified plantation habitat is lacking. We examined the relationship between vegetation structure resulting from intensive forest management practices and the abundance of five species of leaf-gleaning, neotropical migrants: orange-crowned warbler ( Oreothlypis celata (Say, 1823)), Wilson’s warbler ( Wilsonia pusilla (A. Wilson, 1811)), MacGillivray’s warbler ( Oporornis tolmiei (J.K. Townsend, 1839)), Swainson’s thrush ( Catharus ustulatus (Nuttall, 1840)), and black-headed grosbeak ( Pheucticus melanocephalus (Swainson, 1827)). All species, except MacGillivray’s warbler, showed positive associations with the amount of early seral hardwood cover as fledglings, breeding adults, or both. However, the relative magnitude of these associations varied, suggesting that other factors may also have influenced avian responses. Abundances of breeding pairs and young are likely to show positive responses to management practices that increase early seral hardwood cover in regenerating stands. If adopted at landscape and regional scales, such practices may positively influence population trends of several declining bird species.

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Forest degradation, not loss, drives widespread avian population declines

10.21203/rs.3.rs-686817/v1 ◽

2021 ◽

Author(s):

Matthew Betts ◽

Zhiqiang Yang ◽

Adam Hadley ◽

Josee Rousseau ◽

Joseph Northrup ◽

...

Keyword(s):

Habitat Loss ◽

Forest Cover ◽

Bird Species ◽

Forest Degradation ◽

Breeding Habitat ◽

Population Declines ◽

Distribution Models ◽

Eastern Canada ◽

Bird Abundance

Abstract In many regions of the world, forest management has reduced old forest and simplified forest structure and composition via reliance on monoculture tree plantations. We hypothesized that such forest degradation has resulted in long-term habitat loss for forest-associated bird species of eastern Canada (130,017 km2) which, in turn, has affected bird population declines. Back-cast species distribution models revealed that despite little change in overall forest cover, breeding habitat loss occurred for 66% of the 54 most common species from 1985-2020. This habitat loss was strongly associated with population declines for 72% of species, as quantified in an independent, long-term dataset. Since 1985, net forest bird abundance has declined in this region by an estimated 33-104 million birds due to habitat loss alone. The effects of forest degradation may therefore be a primary cause of biodiversity decline in managed forest landscapes.

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Influence of cliffs on bird community diversity

Canadian Journal of Zoology ◽

10.1139/z97-195 ◽

1998 ◽

Vol 76 (2) ◽

pp. 278-287 ◽

Cited By ~ 10

Author(s):

J D Matheson ◽

D W Larson

Keyword(s):

Bird Species ◽

Bird Community ◽

Community Diversity ◽

Bird Species Richness ◽

Narrow Component ◽

Habitat Features ◽

Habitat Mosaic ◽

The North ◽

Talus Slope ◽

Additive Influence

Cliffs along the Niagara Escarpment in Ontario, Canada, support a long, narrow presettlement forest that includes three distinct geomorphic and vegetation zones: cliff edge, cliff face, and talus slope. This unique landform provides an opportunity to evaluate differences in bird communities between the escarpment and adjacent forest relative to habitat features. We sampled forest birds 12 times during the summer of 1994 in plots located in plateau forests, on talus slope, at cliff edges, and on cliff faces. Eleven habitat variables considered important to birds were also sampled in the plots. We arranged plots along six randomly spaced transects at a south site and a north site. Both sites had the consistent habitat heterogeneity considered important to birds. Bird species richness and composition responded to this heterogeneity, but differently at each site: plateau deciduous forests always had the lowest richness and the simplest species composition, whereas both cliff edges and talus slopes had a higher diversity of birds. Cliff faces had large numbers of species in the south but smaller numbers in the north. Escarpment zones form a habitat mosaic that supports many species not found in the adjacent forest and is consistent with the effect of habitat edge. The results suggest that cliffs represent a significant additive influence on avian biodiversity, even when the cliff is a very narrow component of the landscape.

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Using Bioacoustics to Examine Vocal Phenology of Neotropical Migratory Birds on a Wild and Scenic River in Arizona

Birds ◽

10.3390/birds2030019 ◽

2021 ◽

Vol 2 (3) ◽

pp. 261-274

Author(s):

Heather L. Bateman ◽

Sidney B. Riddle ◽

Erin S. Cubley

Keyword(s):

Sonoran Desert ◽

Migratory Birds ◽

Riparian Forest ◽

Bird Species ◽

Migratory Bird ◽

Bird Diversity ◽

Yellow Warbler ◽

Habitat Features ◽

The Usa ◽

Vocal Activity

Passive acoustic recorders have been used successfully as automated survey tools to detect terrestrial wildlife. However, few studies have monitored Neotropical migratory bird use of riparian forest habitat using this technology. Within dryland ecosystems, the forests along rivers support high bird diversity. Many bird species of conservation concern require these floodplain forest habitats for foraging, migration stop-overs, and breeding. Few studies have explored the use of acoustic records in riverine systems designated for conservation for their natural resource value via the Wild and Scenic Rivers Act in the USA. Using acoustic recorders, we document vocal activity of four riparian-obligate species (Bell’s Vireo, Vireo bellii; Summer Tanager, Piranga rubra; Yellow Warbler, Setophaga petechial; and Yellow-billed Cuckoo, Coccyzus americanus) to determine species occurrence along a Wild and Scenic River. We established three study reaches along the perennial Lower Verde River, in the Sonoran Desert of central Arizona, USA. Nine acoustic recorders were used over the period of 80–120 days during the summer of 2018. We measured vegetation composition and structure in 100 m2 plots paired with acoustic recorders. Visualizing vocal activity showed that three species were calling and singing at each reach; whereas, one species, the cuckoo, had fewer recordings and occurred later in the summer. We demonstrate the utility of acoustic monitoring even when applied to rare birds in complex riparian habitats. This information is important for land management and conservation efforts concerning these species of interest and identifying important habitat features in Southwestern US riparian woodlands.

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Habitat and Landscape Suitability as Indicators of Bird Abundance in Created and Restored Wetlands

ISRN Ecology ◽

10.5402/2011/297684 ◽

2011 ◽

Vol 2011 ◽

pp. 1-10 ◽

Cited By ~ 3

Author(s):

Jordan W. Mora ◽

John N. Mager III ◽

Douglas J. Spieles

Keyword(s):

Bird Species ◽

Land Development ◽

Logistic Models ◽

Field Measurements ◽

Road Density ◽

Bird Abundance ◽

Aerial Photos ◽

Landscape Variables ◽

Buffer Width ◽

Landscape Scales

We used aerial photography, field measurements, and bird surveys to evaluate 7 Ohio mitigation wetlands for their capacity to support avian guilds at both local and landscape scales. At the local scale, we assessed each wetland with habitat suitability indices (HSI) for eight wetland-dependent bird species as indicators for four guilds: wading, diving, dabbling, and emergent dependent. We characterized landscapes within 2.5 km of each wetland by measuring the buffer width, road density, connectedness, and anthropogenic land development. The changes in landscape variables over time were determined by comparison of aerial photos taken near the time of wetland construction and near the time of this study. Bird abundance data were poorly correlated with HSI scores but were well described with logistic models of buffer width, wetland area, and road density. Our results suggest that landscape variables are better predictors of bird abundance than HSI scores for these guilds in these wetlands.

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Habitat selection of an endangered European farmland bird, the Ortolan Bunting Emberiza hortulana, in two contrasting landscapes: implications for management

Bird Conservation International ◽

10.1017/s0959270918000060 ◽

2018 ◽

Vol 29 (1) ◽

pp. 144-158 ◽

Cited By ~ 1

Author(s):

MARTIN ŠÁLEK ◽

VÍT ZEMAN ◽

RADOVAN VÁCLAV

Keyword(s):

Czech Republic ◽

Habitat Heterogeneity ◽

Bird Species ◽

Habitat Associations ◽

Woody Vegetation ◽

The Czech Republic ◽

Habitat Features ◽

Farmland Bird ◽

Emberiza Hortulana ◽

Ortolan Bunting

SummaryEffective conservation measures for any bird species across their distribution ranges require detailed knowledge of landscape-specific differences in habitat associations. The Ortolan Bunting Emberiza hortulana is a farmland bird species, which experienced massive population declines during the recent decades and has become a conservation priority in many European countries. Thus, identification of the key habitat features is an important prerequisite for the conservation of the species. Here we investigate habitat associations of the Ortolan Bunting for the remaining breeding population of the species in the Czech Republic. This population is remarkable by its distribution in two markedly different environments – farmland and post-mining landscapes. The main objectives of this study were to identify habitat features associated with Ortolan Bunting occurrence within the two contrasting landscapes and at two spatial scales. Our results reveal a high degree of habitat plasticity by Ortolan Buntings in the Czech Republic which was revealed by the landscape- and scale- specific habitat associations. Habitat heterogeneity, in terms of compositional and configurational diversity, and the cover of bare ground were the most important predictors of Ortolan Bunting occurrence in both landscape types. In farmland, the species occurrence was positively associated with shrub and woody vegetation, poppy fields and set-asides, and negatively associated with grasslands, gardens/orchards, seedlings and urban habitats. In the post-mining landscape, the cover of herb vegetation and greater slope steepness and terrain ruggedness were most important habitat features. Ortolan Buntings in the post-mining landscape appear to avoid patches with a higher cover of shrub and woody vegetation, forests, seedlings and urban areas. We propose that conservation measures for Ortolan Buntings should focus on enhancing farmland habitat heterogeneity, but also on regulating the rate of succession in disturbed environments, such as post-mining landscapes.

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Conservation cobenefits from air pollution regulation: Evidence from birds

Proceedings of the National Academy of Sciences ◽

10.1073/pnas.2013568117 ◽

2020 ◽

Vol 117 (49) ◽

pp. 30900-30906 ◽

Cited By ~ 1

Author(s):

Yuanning Liang ◽

Ivan Rudik ◽

Eric Yongchen Zou ◽

Alison Johnston ◽

Amanda D. Rodewald ◽

...

Keyword(s):

Air Pollution ◽

Large Scale ◽

Population Decline ◽

The United States ◽

Bird Conservation ◽

Bird Abundance ◽

Bird Populations ◽

The Past ◽

Pollution Regulation ◽

Air Pollution Regulation

Massive wildlife losses over the past 50 y have brought new urgency to identifying both the drivers of population decline and potential solutions. We provide large-scale evidence that air pollution, specifically ozone, is associated with declines in bird abundance in the United States. We show that an air pollution regulation limiting ozone precursors emissions has delivered substantial benefits to bird conservation. Our estimates imply that air quality improvements over the past 4 decades have stemmed the decline in bird populations, averting the loss of 1.5 billion birds, ∼20% of current totals. Our results highlight that in addition to protecting human health, air pollution regulations have previously unrecognized and unquantified conservation cobenefits.

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