Data from: Anthropogenic noise and vegetation cover affect the vocalizations of resident Oriental magpie-robins in Kathmandu Valley, Nepal
Data files
Sep 08, 2026 version files 22.36 KB
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Juvenile_calls_of_OMR.csv
3.43 KB
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README.md
4.93 KB
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songs_of_OMR.csv
7.93 KB
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Submissive_calls_of_OMR.csv
3.17 KB
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Territorial_calls_of_OMR.csv
2.90 KB
Abstract
Urbanization is a major factor accounting for land transformation globally. Kathmandu is now one of the most rapidly urbanizing areas in the world. Urbanization and population growth, in turn, lead to increasing noise pollution that impacts biodiversity in a variety of ways. Anthropogenic noises can cause ‘signal masking’ in bird communities, thus creating obstacles in acoustic signals for communication, territorial defense, and mate attraction. This study assessed the effects of anthropogenic noise on the vocalizations (both calls and songs) of the Oriental Magpie-robin (OMR) in the Kathmandu Valley. Vocal recordings of OMRs were conducted from September to October 2022 (for calls) and from February to March 2023 (for songs) at 31 randomly selected sites in the Kathmandu Valley. The level of anthropogenic noise at the sampling sites also was measured concurrently and ranged between 31.00 and 85.90 dB, with the highest levels observed in the urban areas. The minimum frequency of submissive calls was positively correlated with anthropogenic noise level, whereas the number of elements of the calls was negatively correlated with it. No other relationships between calls or song parameters and anthropogenic noise levels were observed. Similarly, the minimum frequency, frequency range, the number of elements of submissive calls, and the maximum frequency of songs differed with the urban gradient but not with other calls or song parameters. We recommend that vegetation structures be increased in the urban areas of the Kathmandu Valley to help mitigate the impact of anthropogenic noise.
https://doi.org/10.5061/dryad.8gtht76ww
Description of the data and file structure
This dataset contains OMR calls and songs data recorded in the field and the environmental variables from the acoustic monitoring sites.
The data are in CSV format:
- Juvenile_calls_of_OMR.csv
- Songs_of_OMR.csv
- Submissive_calls_of_OMR.csv
- Territorial_calls_of_OMR.csv
This dataset contains data on Oriental Magpie Robins’ (OMR) vocalizations, which were recorded daily from 06:00 a.m. to 11:00 a.m. from September to October 2022 (for calls, during the post-breeding season), and from the end of February to March 2023 (for songs, during the breeding season). Of the 43 sampling sites surveyed, OMR calls were recorded at 30 sites and songs were recorded at 31 sites. For recording, a Zoom H2n Stereo/Surround-Sound Portable recorder (model number: H2n, sampling rate 96 kHz, resolution 24-bit, and WAV file format) with a BOYA (BY-PVM1000L) shotgun microphone was used.
The major data contains sampling ID, urbanization gradient, Wav file no., Temperature, Humidity, Average noise, Distance from observer to bird, Latitude, Longitude, Altitude, Perched on tree/wire, Strata if tree, Sex, Lowest frequency, Highest frequency Average low frequency, Average high frequency, Average delta time, Average number of elements, Average length of strophe, Average frequency range, Lowest number of elements, Highest number of elements, and Average time interval.
- Sampling ID is the unique code given for each acoustic record of the particular category.
- District- Kathmandu Valley has three districts (Kathmandu, Bhaktapur and Lalitpur). It explains the district to which the sampling locality belongs.
- Gradient- habitat categorized based on the NDVI values- rural, suburban, and urban
- Wav file no- ID of the audio file of OMR recorded in the field
- Temperature- Aerial temperature at the time of call/song recording recorded using a digital Hygrometer
- Humidity- Air humidity at the time of call/song recording, recorded using a digital Hygrometer
- Average noise- background noise in dB at the time of call/song recording, which was measured by a sound level meter (Mengshen Digital Precision Instrument, model number: MS-M80A, frequency range of 30 dB to 130 dB).
- Maximum noise- Maximum noise level recorded in dB at the sampling duration.
- Minimum noise- minimum level of noise in dB at the sampling duration
- Distance from observer to bird- aerial distance recorded using a range finder
- Latitude- latitude of the sampling point in degree decimal format
- Longitude- longitude of the sampling point in degree decimal format
- Altitude- Elevation of the sampling point in meters above sea level (masl)
- Perched on tree/wire- the substrate on which the OMR was perched
- Strata if tree- lower, middle, or higher strata on which the bird was perching while recording the call.song
- Sex- male or female OMR, recorded when confirmed
- Lowest frequency- minimum frequency of the OMR call/song
- Highest frequency- Maximum frequency of the OMR call/song
- Average low frequency: Average value of the low frequency zone of the vocalization
- Average high frequency: Average value of the high frequency zone of the vocalization
- Average delta time: the difference in seconds between the exact end time and start time of a specific bird vocalization
- Average number of elements: Number of elements in call/ verse of a song
- Average length of strophe: The time interval between call/ verse in a song
- Average frequency range: Difference between the maximum and minimum frequency
- Lowest number of elements: Minimum number of elements per vocalization
- Highest number of elements: Maximum number of elements per vocalization
- Average time interval: Time interval between two successive calls or two successive songs
- NDVI- The Normalized Difference Vegetation Index (NDVI) of the random sites in the Kathmandu Valley were calculated from the Landsat8 image using QGIS version 3.28 with the help of the ‘Zonal statistics’ tool.
The dataset "Juvenile_calls_of_OMR.csv" contains 21 records and 24 features related to bioacoustic recordings, geographical and environmental variables, focusing on the calls of juvenile OMR.
The dataset "Submissive_calls_of_OMR.csv" consists of 25 records and 195 features that document the submissive vocalizations of the OMR in relation to various environmental and biological factors.
The dataset "Territorial_calls_of_OMR.csv" consists of 24 records and 19 features. It focuses on the bioacoustic properties of the OMR territorial songs, which are typically used to defend space or attract mates.
The dataset "songs_of_OMR.csv" contains 62 records and 21 features on the "songs" of the OMR.
Calls and songs of the Oriental Magpie Robin were recorded using a Zoom H2n recorder (sampling rate 96kHz, resolution 24-bit, and WAV file format) with a BOYA (BY-PVM1000L) shotgun microphone. Only calls and songs of perched birds were recorded by approaching them as close as possible without alarming them.
To reduce the recording of the same bird twice, no songs were recorded within the 200 m of the recorded bird, but if another bird was observed singing while recording one individual, then the second bird was also recorded even if it was closer than 200m (Wolfenden et al. 2019).
A sound level meter (Mengshen Digital Precision Instrument) was used to measure anthropogenic noise. The noise was measured for two minutes immediately after bird vocalization stopped (Brumm 2004). The meter was kept 1.2 m above the ground to avoid the sound degraded by reflecting surfaces (Hanafi et al. 2019).
Acoustic data were extracted using Raven Pro 1.6 software (Cornell Lab of Ornithology, Ithaca, NY, USA) from spectrograms of the recorded vocalizations [spectrogram settings: Hamming window Fast Faurier Transformation (FFT) size= 512].