A Comparison of Point Counts and Sound Recording as Bird Survey Methods in Amazonian Southeast Peru

The Condor ◽  
2000 ◽  
Vol 102 (4) ◽  
pp. 887-893 ◽  
Author(s):  
John Haselmayer ◽  
James S. Quinn
Keyword(s):  
Survey Methods ◽  
Sound Recording ◽  
Point Counts ◽  
Bird Survey

scholarly journals Incorporating Availability for Detection in Estimates of Bird Abundance

The Auk ◽  
2007 ◽  
Vol 124 (1) ◽  
pp. 96-106 ◽  
Author(s):  
Duane R. Diefenbach ◽  
Matthew R. Marshall ◽  
Jennifer A. Mattice ◽  
Daniel W. Brauning
Keyword(s):  
Survey Methods ◽  
Distance Sampling ◽  
Sampling Period ◽  
Bird Abundance ◽  
Point Counts ◽  
Variance Estimators ◽  
Bird Survey ◽  
Detection Probabilities ◽  
Ammodramus Henslowii ◽  
Further Development

Abstract Several bird-survey methods have been proposed that provide an estimated detection probability so that bird-count statistics can be used to estimate bird abundance. However, some of these estimators adjust counts of birds observed by the probability that a bird is detected and assume that all birds are available to be detected at the time of the survey. We marked male Henslow's Sparrows (Ammodramus henslowii) and Grasshopper Sparrows (A. savannarum) and monitored their behavior during May-July 2002 and 2003 to estimate the proportion of time they were available for detection. We found that the availability of Henslow's Sparrows declined in late June to <10% for 5- or 10-min point counts when a male had to sing and be visible to the observer; but during 20 May-19 June, males were available for detection 39.1% (SD = 27.3) of the time for 5-min point counts and 43.9% (SD = 28.9) of the time for 10-min point counts (n = 54). We detected no temporal changes in availability for Grasshopper Sparrows, but estimated availability to be much lower for 5-min point counts (10.3%, SD = 12.2) than for 10-min point counts (19.2%, SD = 22.3) when males had to be visible and sing during the sampling period (n = 80). For distance sampling, we estimated the availability of Henslow's Sparrows to be 44.2% (SD = 29.0) and the availability of Grasshopper Sparrows to be 20.6% (SD = 23.5). We show how our estimates of availability can be incorporated in the abundance and variance estimators for distance sampling and modify the abundance and variance estimators for the double-observer method. Methods that directly estimate availability from bird counts but also incorporate detection probabilities need further development and will be important for obtaining unbiased estimates of abundance for these species. Incorporación de la Disponibilidad para la Detección en las Estimaciones de Abundancia de Aves

scholarly journals Autonomous bird sound recording outperforms direct human observation: Synthesis and new evidence

2017 ◽  
Author(s):  
Kevin Darras ◽  
Péter Batáry ◽  
Brett Furnas ◽  
Irfan Fitriawan ◽  
Yeni Mulyani ◽  
...  
Keyword(s):  
Species Richness ◽  
Signal To Noise Ratio ◽  
Survey Methods ◽  
Meta Analysis ◽  
High Signal ◽  
List Type ◽  
Sound Recording ◽  
Data Types ◽  
Point Counts ◽  
Recording Techniques

Abstract1)Autonomous sound recording techniques have gained considerable traction in the last decade, but the question still remains whether they can replace human observation surveys to sample some animal taxa. Especially bird survey methods have been tested using classical point counts and autonomous sound recording techniques.2)We review the latest information by comparing both survey methods' standardization, verifiability, sampling completeness, data types, compatibility, and practicality by means of a systematic review and a meta-analysis of alpha and gamma species richness levels sampled by both methods across 20 separate studies.3)Although sound recording surveys have hitherto not enjoyed the most effective setups, they yield very similar results in terms of alpha and gamma species richness. We also reveal the crucial importance of the microphone (high signal-to-noise ratio) as the sensor that replaces human senses.4)We discuss key differences between both methods, while richness estimates are closely related and 81% of all species were detected by both methods. Sound recording techniques provide a more powerful and promising tool to monitor birds in a standardized, verifiable, and exhaustive way against the golden standard of point counts. Advantages include the capability of sampling continuously through day or season and of difficult-to-reach regions in an autonomous way, avoidance of observer bias and human disturbance effects and higher detection probability of rare species due to extensive recordings.

Influence of moonlight on nightjars’ vocal activity: a guideline for nightjar surveys in Europe

Biologia ◽  
2015 ◽  
Vol 70 (7) ◽  
Author(s):  
Luís Reino ◽  
Miguel Porto ◽  
Joana Santana ◽  
Tomasz S. Osiejuk
Keyword(s):  
Survey Methods ◽  
Mediterranean Area ◽  
Lunar Cycle ◽  
Early Summer ◽  
Factors Affecting ◽  
Moon Phases ◽  
Vocal Behaviour ◽  
Bird Survey ◽  
Southern Portugal ◽  
Vocal Activity

AbstractStrictly nocturnal or crepuscular habits on birds are restricted to a very limited number of species such as nightjars. Physiological skills of these species combined with ecological and behavioural adaptations provide them the ability to colonise a less competitive niche. Nightjars’ nocturnal ecological adaptations have been largely neglected on bird survey methods, which can bias the obtained results. Here, we studied the factors affecting vocal activity of two nightjar species, red-necked nightjar Caprimulgus ruficollis and European nightjar C. europaeus in a Mediterranean area of southern Portugal by modelling observed vocal activity of both species as a function of astronomic variables, particularly moon phase and day of the year. Red-necked nightjar vocal behaviour was positively associated with brighter moon phases and springtime, whereas European nightjar was only influenced by the season, being more active in the summer. This reveals the importance of light conditions on vocal activity of the former species. We suggest that specifically designed field surveys for these species should be preferentially conducted during brighter nights, when the lunar cycle is close to full moon. Furthermore, positive contacts with birds are maximized from late spring to early summer, at least for the red-necked nightjar.

scholarly journals A RAPID BIRD SURVEY TO CONSERVATION AREA OF INDUSTRIAL ACACIA TIMBER PLANTATION, SOUTH SUMATRA PROVINCE; WITH COMPARISON TO THREE DIFFERENT METHODS

2016 ◽  
Vol 2 (2) ◽  
Author(s):  
Muhammad Iqbal ◽  
Indra Yustian ◽  
Doni Setiawan ◽  
Rio Firman Saputra ◽  
Catur Yuono Prasetyo ◽  
...  
Keyword(s):  
Survey Methods ◽  
Bird Species ◽  
Bird Diversity ◽  
International Union ◽  
Conservation Area ◽  
Swamp Forest ◽  
Number Of Species ◽  
Transect Line ◽  
Bird Survey ◽  
Near Threatened

A rapid bird survey was done in a small conservation area of industrial timber concession of PT BMH (Bumi Mekar Hijau), namely KPPN (Kawasan Pelestarian Plasma Nutfah), South Sumatra Province. The area has 448 ha, dominated by degraded secondary swamp forest surrounded by Acacia plantation. Three survey methods were applied to assess bird diversity in this area: transect line, mist-netting and audio-visual station recording. A total of 36 species was recorded during survey. Among three methods applied, transect line is the most effective method to detect more bird species (29 species), followed by audio-visual station recording (26 species) and mist-netting (three species). There are eight species which protected by Indonesian law and two birds are listed as Near Threatened (NT) by International Union for Conservation of Nature or IUCN. Although number of species birds recorded are not significance, but this area still support habitat for various birds diversity, and the forest remaining should be well-managed to support its conservation goals.

scholarly journals Optimising tropical forest bird surveys using passive acoustic monitoring and repeated short-duration point counts

2020 ◽  
Author(s):  
Oliver C. Metcalf ◽  
Jos Barlow ◽  
Stuart Marsden ◽  
Nárgila Gomes de Moura ◽  
Erika Berenguer ◽  
...  
Keyword(s):  
Tropical Forests ◽  
Short Duration ◽  
Survey Methods ◽  
Alpha Diversity ◽  
Gamma Diversity ◽  
Point Count ◽  
Point Counts ◽  
Detection Frequency ◽  
Standard Duration ◽  
Avian Biodiversity

AbstractEstimation of avian biodiversity is a cornerstone measure of ecosystem condition, with turnover in avian community composition underpinning many studies of land-use change in tropical forests. Surveys conducted using autonomous recorders have been frequently found to be more efficient than traditional point-count surveys. However, there has been limited research into optimal survey duration, despite autonomous recordings allowing for many more repeats of short-duration surveys with relative ease in comparison to traditional survey methods.We use an acoustic dataset collected from a region of very high avian biodiversity - the eastern Brazilian Amazon - to test the effect of using short-duration surveys to increase temporal coverage without increasing total survey duration. We use this dataset to assess whether a survey protocol consisting of 240 15-second surveys at 29 locations, ‘short-duration surveys’, has an influence on resulting alpha and gamma diversity, and detection frequency, than ‘standard-duration surveys’ of four 15-minute surveys per location.We find that repeated short-duration surveys outperform longer duration surveys in every metric considered herein, with short-duration surveys predicted to detect approximately 50% higher alpha diversity, and 10% higher gamma diversity. Short-duration surveys also detect species more often, at more survey locations. Conversely, standard-duration surveys are almost four times more likely to produce false negatives (i.e. to fail to detect species presence). Whilst there is no difference between the proportion of uncommon species detected by the two methods, when considering species detected multiple times at multiple locations, short-duration surveys detected three times more uncommon species than standard-duration surveys.We conclude that short-duration recorded surveys should be considered the primary method for sampling the species richness of bird communities in tropical forests and is likely to be preferable to longer duration or traditional surveys in most environments.

Sound recording of bird vocalisations in forests. I. Relationships between bird vocalisations and point interval counts of bird numbers - a case study in statistical modeling

2004 ◽  
Vol 31 (2) ◽  
pp. 195 ◽  
Author(s):  
R. B. Cunningham ◽  
D. B. Lindenmayer ◽  
B. D. Lindenmayer
Keyword(s):  
Sound Recording ◽  
Activity Data ◽  
Point Count ◽  
Point Counts ◽  
Number Of Species ◽  
Eastern Australia ◽  
Vocal Activity ◽  
Fragmented Forests ◽  
Point Count Method ◽  
The Relationship

Morning vocal activity data for birds were collected using automatic sound recorders at 165 sites in fragmented forests at Tumut in south-eastern Australia. A model was developed to describe the statistical properties of the vocal activity data and study the relationship between the number of 'elements' (or notes) broadcast by birds and the number of birds recorded by human observers. We discuss the practical issues of finding a model where variance heterogeneity and skewness is a feature of the data, while the context of the problem required that multiplicative relationships be preserved. A satisfactory fit to our vocal activity data was obtained by using a Gamma distribution.For most groups of birds, the observed relationships between vocal activity and the number of birds recorded by human point counts were weak but statistically significant.Our analysis suggests that these data provide limited useful information about vocal activity per bird. Automatic sound-recording data may be informative for drawing inferences about temporal patterns in vocal activity but do not seem useful as a method for estimating the abundance of birds. A significant relationship was identified between the number of species vocalising, as measured by sound recorders, and the number of species observed by point count method. However, the relationship was far from isometric and there were many more species detected by the sound recorders than by human observers.Results from analyses of vocal activity data gathered at Tumut were confirmed by additional data obtained in a subsequent, small calibration study in the Namadgi National Park in the Australian Capital Territory.

scholarly journals Comparisons of Line Transect and Point Count Survey Methods by Estimating Density of Grey Squirrel Sciurus Carolinensis

2016 ◽  
Vol 7 (1) ◽  
pp. 17 ◽  
Author(s):  
Mariwan Rahim
Keyword(s):  
Survey Methods ◽  
Line Transect ◽  
Sciurus Carolinensis ◽  
Animal Population ◽  
Grey Squirrel ◽  
Density Estimates ◽  
East Anglia ◽  
Point Count ◽  
Point Counts ◽  
Count Surveys

<p>The methods have used to study animal population must be defined clearly at the beginning of the project. We compared line transect and point count survey methods to estimating the density of grey squirrel at University of East Anglia campus (UEA), Norwich-United Kingdom. Across the entire UEA campus we surveyed 0.43698 ha of the 146 ha of the campus area. A total of 21 squirrels were observed during survey between 21<sup>st</sup>-26<sup>th</sup> in December 2013. Nine individuals were observed during line transect and twelve individuals were observed during point counts. The average number of species detected was differing between the two methods. Density estimates of grey squirrel from the two methods were different. Densities of grey squirrel as estimated by point count surveys were higher than those by line transect count surveys. Our results indicate that it is important to account for different survey methods when comparing the two methods to estimate the grey squirrel.</p>

scholarly journals Comparison of point and roadside transect methods to evaluate the abundance and richness of diurnal raptors in the arid region of Rajasthan

PLoS ONE ◽  
2021 ◽  
Vol 16 (12) ◽  
pp. e0259805
Author(s):  
Govind Tiwari ◽  
Puneet Pandey ◽  
Rahul Kaul ◽  
Hang Lee ◽  
Randeep Singh
Keyword(s):  
Species Richness ◽  
Average Length ◽  
Survey Methods ◽  
Survey Method ◽  
Point Count ◽  
Point Counts ◽  
Significant Difference ◽  
Unidentified Species ◽  
Species Richness And Abundance ◽  
Point Count Method

Diurnal raptors show a wider distribution compared to other groups of birds including passerines, woodpeckers, and seriemas, but occur at lower-than-expected densities. Estimating the precise abundance is essential to achieve conservation goals but the methods used to estimate the populations of birds need to be appropriate to arrive at meaningful conclusions. We compared the two survey methods: roadside point count and strip transects, for estimating species richness and abundance of raptors in the arid landscape of Rajasthan. Roadside point counts and roadside strip transects were done on 50 transects between December 2019- February 2020 (with an average length of 20 km and a total distance of 3000 km) to assess the species richness and abundance of raptors. A total of 2954 observations of raptors belonging to 35 species were recorded using both methods. Mann Whitney U test result showed no significant difference in species richness and abundance estimates between both methods (p = 0.206). The point count method yielded a higher relative abundance of 2.79 individuals [10 km2]-1h-1 than the 1.90 individuals [10 km2]-1h-1 obtained during the strip transect. Also, the number of unidentified species were less for point counts. Extrapolation values indicated that both the methods do not differ much for the detection of unsampled species. The choice of survey method depends on the objectives of the study, but our results favor the use of point counts rather than strip transects to survey raptors in open habitats. The information generated from this study is expected to provide the most efficient method to study the abundance and distribution of raptors in similar landscapes.

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