Examining the Effect of Helicopter Noise on Birds at Hawaii Volcanoes National Park
Karen Gallardo (1), Kristina Paxton (2), Patrick Hart (2); 1. Tropical Conservation Biology and Environmental Science, University of Hawaii at Hilo; 2. Department of Biology, University of Hawaii at Hilo
~ Soundscape Ecology – Describes the relationship between the landscape and the composition of its sound (Pijanowski et al. 2011)
- Biophony – biotic sounds
- Geophony – geophysical sounds
- Anthrophony – anthropogenic sounds
~ Can visualize the soundscape by using a spectrogram
- Anthrophony is a relatively new addition to the soundscape
~ Animals respond to anthrophony
- Noise changes bird communities and disrupts predator-prey interactions (Francis et al. 2009)
- Noise affects vocalization dynamics of birds
· Songs louder and more repetitive (Pieretti and Farina 2013)
- Aircraft noise increases stress behavior in individual bird species
· Ducks, seabirds, owls, hawks, and eagles exhibited increased stress and agonistic behavior in response to aircraft noise (Andersen et al. 1989, Conomy et al. 1998, Brown 1990, Delaney et al. 1999, Goudie & Jones 2004)
· Bald Eagles responded most often to helicopters in comparison to jets and light planes (Grubb and Bowermann 1997)
~ Helicopter traffic is plentiful on the Big Island
- Before eruption, a lot of flights over native forest at Hawaii Volcanoes National Park (HAVO) to get to Pu’u O’o
- Helicopters would often fly low over the forest. Have seen them <100ft above canopy
· Low-flying helicopters are loud
Introduction
~ Soundscape Ecology – Describes the relationship between the landscape and the composition of its sound (Pijanowski et al. 2011)
- Biophony – biotic sounds
- Geophony – geophysical sounds
- Anthrophony – anthropogenic sounds
~ Can visualize the soundscape by using a spectrogram
- Anthrophony is a relatively new addition to the soundscape
~ Animals respond to anthrophony
- Noise changes bird communities and disrupts predator-prey interactions (Francis et al. 2009)
- Noise affects vocalization dynamics of birds
· Songs louder and more repetitive (Pieretti and Farina 2013)
- Aircraft noise increases stress behavior in individual bird species
· Ducks, seabirds, owls, hawks, and eagles exhibited increased stress and agonistic behavior in response to aircraft noise (Andersen et al. 1989, Conomy et al. 1998, Brown 1990, Delaney et al. 1999, Goudie & Jones 2004)
· Bald Eagles responded most often to helicopters in comparison to jets and light planes (Grubb and Bowermann 1997)
~ Helicopter traffic is plentiful on the Big Island
- Before eruption, a lot of flights over native forest at Hawaii Volcanoes National Park (HAVO) to get to Pu’u O’o
- Helicopters would often fly low over the forest. Have seen them <100ft above canopy
· Low-flying helicopters are loud
A huge mahalo to my committee members, Patrick Hart, Kristina Paxton, Matthew Knope and Bryan Pijanowski; to all the people who helped me in the field, Jeff Wood, Barret Baca, Victor and Edgar Noguera, Leonard Munstermann; to everyone at Hawaii Volcanoes National Park and the National Park Service Natural Sounds and Night Skies Division for their funding, field access, and help: Danielle Foster, Ashley Pipkin, Kurt Fristrup, Serafina Gajate, and the HAVO Mule Packing Program; and to Scott Jorgensen from Blue Hawaiian Helicopters for his input on site selection.
Primary Question
Does helicopter noise affect the vocalizing behavior of native and non-native birds at HAVO?
- Predict that helicopter noise will negatively impact the vocalizing behavior of birds at HAVO.
Significance
- The results of this research will inform the creation of an air tour management plan for HAVO
- First study to quantify the effect of noise on Hawaiian birds
- One of few studies to examine the effect of noise on an entire bird community
Study Site
Study Species
Audio Recording Methods
~ Passive acoustic recorders – during March, April & beginning of May
- Recorded continuously between 7 am - 5 pm
~ Placed recorders 90 m apart from each other to ensure recorder independence
Question:
Which helicopter noise characteristics have the most effect on the amount of time birds spend vocalizing?
- Prediction: Frequency range and Average Power of helicopter noise will have the greatest effect on the amount of time birds spend vocalizing.
Acoustic Analysis Methods
~ To measure noise characterisics:
- For 10 seconds every 20 seconds, measured Delta Frequency (kHz) and Average Power (dB) of helicopter noise
~ To measure bird characteristics
- For 10 seconds every 20 seconds, measured total vocalization time, separated by species
Statistic Analysis Methods
Linear Mixed Model
- Response Variable: total vocalization time (s) by species
- Explanatory Variable: frequency range (Hz) of noise, average power of noise (dB), species
- Random Factor: site
Methods
Study Site
Study Species
Audio Recording Methods
~ Passive acoustic recorders – during March, April & beginning of May
- Recorded continuously between 7 am - 5 pm
~ Placed recorders 90 m apart from each other to ensure recorder independence
Question:
Which helicopter noise characteristics have the most effect on the amount of time birds spend vocalizing?
- Prediction: Frequency range and Average Power of helicopter noise will have the greatest effect on the amount of time birds spend vocalizing.
Acoustic Analysis Methods
~ To measure noise characterisics:
- For 10 seconds every 20 seconds, measured Delta Frequency (kHz) and Average Power (dB) of helicopter noise
~ To measure bird characteristics
- For 10 seconds every 20 seconds, measured total vocalization time, separated by species
Statistic Analysis Methods
Linear Mixed Model
- Response Variable: total vocalization time (s) by species
- Explanatory Variable: frequency range (Hz) of noise, average power of noise (dB), species
- Random Factor: site
Relationship Between Vocalization Time and Noise Characteristics Differs Between Species
Figure 1. Relationship between vocalization time and a) helicopter noise frequency range (Hz) and b) helicopter noise power (dB) for 'Apapane (Himatione sanguinea), 'Ōmaʻo (Myadestes obscurus), Hawaiʻi ʻAmakihi, (Hemignathus virens) Japanese Bush-warbler (Horornis diphone), and Japanese White-eye (Zosterops japonicus). The interaction between frequency range and species had a significant effect on total vocalization time (F = 4.93, df = 107, p < 0.01), as did the interaction between dB and species (F = 4.69, df = 107, p < 0.01). This figure is based on data that does not include site as a random factor.
Helicopter Noise Frequency Results
With increasing helicopter noise:
~ Japanese White-eye vocalization time increased
~ No relationship between vocalization time and frequency of noise for and ʻŌmaʻo , ʻApapane, Hawaiʻi ʻAmakihi and Japanese Bush-warbler
Helicopter Noise Power Results
With increasing helicopter noise:
~ Japanese White-eye vocalization time decreased
~ Hawaiʻi ʻAmakihi vocalization time increased
~ No relationship between vocalization time and noise power for Japanese Bush-warbler, ʻŌmaʻo, and ʻApapane
Preliminary Results
Relationship Between Vocalization Time and Noise Characteristics Differs Between Species
Figure 1. Relationship between vocalization time and a) helicopter noise frequency range (Hz) and b) helicopter noise power (dB) for 'Apapane (Himatione sanguinea), 'Ōmaʻo (Myadestes obscurus), Hawaiʻi ʻAmakihi, (Hemignathus virens) Japanese Bush-warbler (Horornis diphone), and Japanese White-eye (Zosterops japonicus). The interaction between frequency range and species had a significant effect on total vocalization time (F = 4.93, df = 107, p < 0.01), as did the interaction between dB and species (F = 4.69, df = 107, p < 0.01). This figure is based on data that does not include site as a random factor.
Helicopter Noise Frequency Results
With increasing helicopter noise:
~ Japanese White-eye vocalization time increased
~ No relationship between vocalization time and frequency of noise for and ʻŌmaʻo , ʻApapane, Hawaiʻi ʻAmakihi and Japanese Bush-warbler
Helicopter Noise Power Results
With increasing helicopter noise:
~ Japanese White-eye vocalization time decreased
~ Hawaiʻi ʻAmakihi vocalization time increased
~ No relationship between vocalization time and noise power for Japanese Bush-warbler, ʻŌmaʻo, and ʻApapane
Conclusions
~ Response to helicopter noise differs between bird species
~ Hawaii ʻAmakihi and Japanese White-eye seem to be the most responsive to helicopter noise from preliminary data
~ Other bird species may not be responding because habituation may have already taken place, or they are more resilient to helicopter noise
Future Study
~ In addition to the question presented, I will also address:
- Do individual bird species vocalize more prior to the presence of helicopter noise?
- Does the entire bird community vocalize more prior to the presence of helicopter noise?
- Have birds in areas of high helicopter traffic become habituated to helicopter noise?
~ Expand study to include new recording locations to get a broader representation of how these bird species respond to helicopter noise in other parts of the island
Discussion and Future Study
Conclusions
~ Response to helicopter noise differs between bird species
~ Hawaii ʻAmakihi and Japanese White-eye seem to be the most responsive to helicopter noise from preliminary data
~ Other bird species may not be responding because habituation may have already taken place, or they are more resilient to helicopter noise
Future Study
~ In addition to the question presented, I will also address:
- Do individual bird species vocalize more prior to the presence of helicopter noise?
- Does the entire bird community vocalize more prior to the presence of helicopter noise?
- Have birds in areas of high helicopter traffic become habituated to helicopter noise?
~ Expand study to include new recording locations to get a broader representation of how these bird species respond to helicopter noise in other parts of the island
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