scholarly journals Rusty Blackbird (Euphagus carolinus) Foraging Habitat and Prey Availability in New England: Implications for Conservation of a Declining Boreal Bird Species

Diversity ◽  
2021 ◽  
Vol 13 (2) ◽  
pp. 99
Author(s):  
Amanda Pachomski ◽  
Stacy McNulty ◽  
Carol Foss ◽  
Jonathan Cohen ◽  
Shannon Farrell
Keyword(s):  
New England ◽  
Prey Availability ◽  
Bird Species ◽  
Aquatic Invertebrate ◽  
Habitat Characteristics ◽  
Point Count ◽  
Point Counts ◽  
Invertebrate Abundance ◽  
Euphagus Carolinus ◽  
Rusty Blackbird

The Rusty Blackbird (Euphagus carolinus) is an imperiled migratory songbird that breeds in and near the boreal wetlands of North America. Our objective was to investigate factors associated with Rusty Blackbird wetland use, including aquatic invertebrate prey and landscape features, to better understand the birds’ habitat use. Using single-season occupancy modeling, we assessed breeding Rusty Blackbird use of both active and inactive beaver-influenced wetlands in New Hampshire and Maine, USA. We conducted timed, unlimited-radius point counts of Rusty Blackbirds at 60 sites from May to July 2014. Following each point count, we sampled aquatic invertebrates and surveyed habitat characteristics including percent mud cover, puddle presence/absence, and current beaver activity. We calculated wetland size using aerial imagery and calculated percent conifer cover within a 500 m buffer of each site using the National Land Cover Database 2011. Percent mud cover and invertebrate abundance best predicted Rusty Blackbird use of wetlands. Rusty Blackbirds were more likely to be found in sites with lower percent mud cover and higher aquatic invertebrate abundance. Sites with Rusty Blackbird detections had significantly higher abundances of known or likely prey items in the orders Amphipoda, Coleoptera, Diptera, Odonata, and Trichoptera. The probability of Rusty Blackbird detection was 0.589 ± 0.06 SE. This study provides new information that will inform habitat conservation for this imperiled species in a beaver-influenced landscape.

scholarly journals Factors affecting the species richness and composition of bird species in a community managed forest of Nepal

2021 ◽  
Vol 13 (9) ◽  
pp. 19212-19222
Author(s):  
Bishow Poudel ◽  
Bijaya Neupane ◽  
Rajeev Joshi ◽  
Thakur Silwal ◽  
Nirjala Raut ◽  
...  
Keyword(s):  
Diversity Index ◽  
Bird Species ◽  
Habitat Characteristics ◽  
Lower Percentage ◽  
Bird Diversity ◽  
Limited Information ◽  
Managed Forest ◽  
Point Count ◽  
Community Forests ◽  
Wiener Diversity Index

There exists limited information on biodiversity including avifaunal diversity and habitat condition in community forests (CF) of Nepal; thus we aimed to fulfill such gaps in Tibrekot CF of Kaski district. We used the point count method for assessing bird diversity and laid out a circular plot size of radius 5-m within 15-m distance from each point count station for recording the biophysical habitat characteristics. Bird species’ diversity, richness and evenness were calculated using popular indexes and General Linear Model (GLM) was used to test the respective effect of various biophysical factors associated with the richness of bird species. In total, 166 (summer 122, winter 125) bird species were recorded in 46 sample plots. The Shannon-Wiener diversity index was calculated as 3.99 and 4.09, Margalef’s richness index as 16.84 and 17.53 and Pielou’s evenness index as 0.83 and 0.84 for summer and winter, respectively. The influencing factors for richness of bird species were season (χ21, 90= 112.21; P= 0.016) with higher richness in the summer season and low vegetation cover (χ21, 89= 113.88; P= 0.0064) with higher richness in lower percentage cover. Thus, community managed forest should be protected as it has a significant role in increasing bird diversity, which has potential for attracting avifaunal tourism for the benefit of the local communities.

Problems with Avian Point Counts for Estimating Density of Northern Bobwhite—A Case Study

2011 ◽  
Vol 2 (1) ◽  
pp. 117-121 ◽  
Author(s):  
Roger D. Applegate ◽  
Robert E. Kissell ◽  
E. Daniel Moss ◽  
Edward L. Warr ◽  
Michael L. Kennedy
Keyword(s):  
Count Data ◽  
Distance Sampling ◽  
Bird Species ◽  
Northern Bobwhite ◽  
Model Fit ◽  
Point Count ◽  
Point Counts ◽  
Occupancy Estimation ◽  
Detection Probabilities

Abstract Point count data are used increasingly to provide density estimates of bird species. A favored approach to analyze point count data uses distance sampling theory where model selection and model fit are important considerations. We used uniform and half normal models and assessed model fit using χ2 analysis. We were unsuccessful in fitting models to 635 northern bobwhite Colinus virginianus observations from 85 avian point locations spanning 6 y (P ≤ 0.05). Most observations (74%) occurred in the outermost (>100-m) distance radius. Our results violated the assumptions that all observations at the point are detected. The assumption that birds were assigned to the correct distance interval also was probably violated. We caution managers in implementing avian point counts with distance sampling when estimating northern bobwhite population density. We recommend exploring other approaches such as occupancy-estimation and modeling for estimating detection probabilities.

scholarly journals Effects of hunting management on Mediterranean farmland birds

2014 ◽  
Vol 25 (2) ◽  
pp. 166-181 ◽  
Author(s):  
JESÚS CARO ◽  
MIGUEL DELIBES-MATEOS ◽  
ALBA ESTRADA ◽  
RUI BORRALHO ◽  
LUÍS GORDINHO ◽  
...  
Keyword(s):  
Bird Species ◽  
Habitat Characteristics ◽  
Alectoris Rufa ◽  
Game Management ◽  
Farmland Birds ◽  
Point Counts ◽  
Small Game ◽  
Circus Pygargus ◽  
Tetrax Tetrax ◽  
Ground Nesting

SummaryHunting and its associated management have significant costs and benefits for biodiversity conservation, which makes this socio-economic activity highly controversial at both international and regional levels. We investigated relationships between management for small game species (mainly Red-legged Partridges Alectoris rufa and rabbits Oryctolagus cuniculus) and both abundance and richness of farmland and scrubland songbirds, raptors and ground-nesting birds, and on the abundance of three species of conservation concern (Little Bustard Tetrax tetrax, Eurasian Thick-knee Burhinus oedicnemus and Montagu’s Harrier Circus pygargus) in southern Portugal farmland. We compared 12 game estates and 12 matching areas with similar sizes and land uses but no game management. Richness and abundance were estimated from fixed point counts, and were related to game regime (managed or unmanaged), habitat characteristics and census period. Our results showed that game management was associated, albeit weakly, with higher abundance of raptors and ground-nesting birds, but no relationship (either positive or negative) was found for other guilds and species. Habitat was generally the most important factor explaining bird species richness and abundance. Our results suggest possibilities for promoting management systems that could maximize both hunting sustainability and conservation value of managed areas, particularly when management helps to improve or maintain beneficial habitats or practices for farmland birds.

scholarly journals A Double-Observer Approach for Estimating Detection Probability and Abundance From Point Counts

The Auk ◽  
2000 ◽  
Vol 117 (2) ◽  
pp. 393-408 ◽  
Author(s):  
James D. Nichols ◽  
James E. Hines ◽  
John R. Sauer ◽  
Frederick W. Fallon ◽  
Jane E. Fallon ◽  
...  
Keyword(s):  
Detection Probability ◽  
Bird Species ◽  
Field Trials ◽  
Bird Abundance ◽  
Point Count ◽  
Point Counts ◽  
Avian Abundance ◽  
Detection Probabilities ◽  
Sources Of Variation ◽  
Double Observer

Abstract Although point counts are frequently used in ornithological studies, basic assumptions about detection probabilities often are untested. We apply a double-observer approach developed to estimate detection probabilities for aerial surveys (Cook and Jacobson 1979) to avian point counts. At each point count, a designated “primary” observer indicates to another (“secondary”) observer all birds detected. The secondary observer records all detections of the primary observer as well as any birds not detected by the primary observer. Observers alternate primary and secondary roles during the course of the survey. The approach permits estimation of observer-specific detection probabilities and bird abundance. We developed a set of models that incorporate different assumptions about sources of variation (e.g. observer, bird species) in detection probability. Seventeen field trials were conducted, and models were fit to the resulting data using program SURVIV. Single-observer point counts generally miss varying proportions of the birds actually present, and observer and bird species were found to be relevant sources of variation in detection probabilities. Overall detection probabilities (probability of being detected by at least one of the two observers) estimated using the double-observer approach were very high (>0.95), yielding precise estimates of avian abundance. We consider problems with the approach and recommend possible solutions, including restriction of the approach to fixed-radius counts to reduce the effect of variation in the effective radius of detection among various observers and to provide a basis for using spatial sampling to estimate bird abundance on large areas of interest. We believe that most questions meriting the effort required to carry out point counts also merit serious attempts to estimate detection probabilities associated with the counts. The double-observer approach is a method that can be used for this purpose.

scholarly journals Study of the Milky Stork Bird (Mycteria cinerea) Population in Rawa Pacing, Kibang Pacing Village, Menggala Timur Sub-District, Menggala Timur Regency, Lampung Province

2018 ◽  
Vol 6 (2) ◽  
pp. 1
Author(s):  
Faizal Mahdi Syamal ◽  
Sugeng Prayitno Harianto
Keyword(s):  
Data Collection ◽  
Vegetation Structure ◽  
Natural Habitat ◽  
Bird Species ◽  
Distribution Patterns ◽  
Daily Activities ◽  
Point Count ◽  
Illegal Hunting ◽  
Point Counts ◽  
Point Count Method

Kibang Pacing Village with an area of 83.55 km2 had converted that lead to a change of the vegetation structure from multistrata into monostrata that could threaten the wildlife such as the milky stork bird (Mycteria cinerea) that classified as a threatened species. The objectives of this study were to determine the number of individual and distribution patterns of milky stork in Rawa Pacing at Kibang Pacing Village, Menggala Timur Sub-District, Tulang Bawang Regency. Data collection was conducted through direct observation using point count method at 3 (three) point counts. The results observed 513 encounters of the milky stork, showing the most encounter at Point Count 3. The higher encounter occurred in the morning than in the afternoon which because diurnal bird species generally started their daily activities to find foods in the morning. The abundance of milky stork population in Kibang Pacing Village was 126 individuals, showing the highest number at Point Count 3. Illegal hunting and other human activities in Rawa Pacing could potentially cause disruption on natural habitat that may threaten the existence and sustainability of the milky stork bird.  Keywords: milky stork, Mycteria cinerea, pacing swamp, population.

scholarly journals Accounting for point count ambient noise increases population size estimates

2021 ◽  
Author(s):  
Emily K Anderson ◽  
Pete F Kerby-Miller ◽  
Julia M Pupko ◽  
Nathaniel R Sharp ◽  
Kevin S Tolan ◽  
...  
Keyword(s):  
Population Size ◽  
Ambient Noise ◽  
Bird Species ◽  
Natural Environments ◽  
Point Count ◽  
Point Counts ◽  
Sampling Locations ◽  
Population Size Estimates ◽  
Field Season ◽  
Acoustic Environments

Ambient noise is an integral component of natural environments, but it also creates challenges for avian monitoring programs. Ambient noise can mask bird vocalizations from observers during point counts, which may lead to systematic undercounting of birds in noisy environments. Here, we estimate detection probability and population size in models that either account for or omit the influence of ambient noise. We used data for four bird species, from 2228 point counts that were conducted during the 2019 Mountain Birdwatch field season. Community scientists assessed ambient noise using a simple scale. Despite relatively quiet conditions at sampling locations (x = 2.48), our information theoretical approach favored N-mixture models that incorporated ambient noise into the detection function for all four species. At the noisiest sampling locations, our models predicted detection probabilities that were as low as 10% for some species. Accounting for ambient noise resulted in a modest, mean increase of ≤3.29% in the total population size for each species. Following our approach, other researchers can easily incorporate ambient noise assessments into their field protocols and analyses, with minimal costs or added complexity, to increase the comparability of studies conducted within different acoustic environments.

Die Brutvogelfauna eines Nadelwaldes der nördlichen Voralpen nach dem Sturm Lothar

2017 ◽  
Vol 168 (2) ◽  
pp. 59-66
Author(s):  
Pierre Mollet ◽  
René Hardegger ◽  
Res Altwegg ◽  
Pius Korner ◽  
Simon Birrer
Keyword(s):  
Forest Succession ◽  
Coniferous Forest ◽  
Bird Species ◽  
Individual Species ◽  
Mountain Forest ◽  
Breeding Bird ◽  
Point Counts ◽  
Federal Institute ◽  
Central Switzerland ◽  
Bird Fauna

Breeding bird fauna in a coniferous forest in the northern Prealps after storm Lothar In a 70-hectare large coniferous forest located on the northern edge of the Alps in central Switzerland, Canton of Obwalden, at an altitude of 1260 to 1550 metres above sea level, we surveyed the local breeding bird fauna in 2002 and 2013 by means of point counts as well as additional area searches for rare species. In December 1999, hurricane Lothar caused two large windthrow areas and several smaller areas with scattered throws in the survey range. We found a total of 48 breeding bird species, which is a very diverse species composition for a mountain forest. In the eleven years between surveys, a decline in distribution or abundance was recorded for four species, while seven species showed an increase; a further four species showed no change. For the remaining species, the data sets were too small to reliably estimate changes. A comparison with forest structure data provided by the Swiss Federal Institute of Forest, Snow and Landscape Research WSL revealed that for five bird species, the changes in distribution or abundance could be explained at least partially by forest succession. In order to obtain realistic distribution and abundance values in this kind of breeding bird survey, it is essential to collect large enough samples and to consider the detection probability of each individual species using appropriate statistical methods.

scholarly journals On the use of 10-minute point counts and 10-species lists for surveying birds in lowland Atlantic Forests in southeastern Brazil

2012 ◽  
Vol 52 (28) ◽  
pp. 333-340 ◽  
Author(s):  
Vagner Cavarzere ◽  
Thiago Vernaschi Vieira da Costa ◽  
Luís Fábio Silveira
Keyword(s):  
Rapid Assessment ◽  
Southeastern Brazil ◽  
Point Counting ◽  
Point Count ◽  
Point Counts ◽  
Time Period ◽  
Minute Point ◽  
Species Lists ◽  
Point Count Method ◽  
Breeding Seasons

Due to rapid and continuous deforestation, recent bird surveys in the Atlantic Forest are following rapid assessment programs to accumulate significant amounts of data during short periods of time. During this study, two surveying methods were used to evaluate which technique rapidly accumulated most species (> 90% of the estimated empirical value) at lowland Atlantic Forests in the state of São Paulo, southeastern Brazil. Birds were counted during the 2008-2010 breeding seasons using 10-minute point counts and 10-species lists. Overall, point counting detected as many species as lists (79 vs. 83, respectively), and 88 points (14.7 h) detected 90% of the estimated species richness. Forty-one lists were insufficient to detect 90% of all species. However, lists accumulated species faster in a shorter time period, probably due to the nature of the point count method in which species detected while moving between points are not considered. Rapid assessment programs in these forests will rapidly detect more species using 10-species lists. Both methods shared 63% of all forest species, but this may be due to spatial and temporal mismatch between samplings of each method.

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