Exposure to Urban Noise May Influence Morphological Traits on Zebra Finches

A study looked at the effects of anthropogenic noise on zebra finch cognition, beak color, and growth.

Adult zebra finches were first tested on a battery of cognition essays while being exposed to playbacks of urban noise versus birds tested without noise.

The birds took longer to learn a novel foraging task and an association-learning task due to urban noises.

Urban noise exposure also caused treated male finches to develop less bright beak coloration and females to develop brighter orange beak coloration than untreated birds.

Effects of urban noise on Zebra Finches

(Photo : CARL DE SOUZA/AFP via Getty Images)

There is an increasing issue that human activity noise is harming wildlife in urban areas, as per ScienceDaily.

Urban noise contains a wide range of frequencies, and sound types, such as traffic, and varying amplitudes, including sounds with sudden onset times that can be startling.

While research has shown that noise pollution affects cognitive performance in some animal species, including birds, a study conducted by Florida Atlantic University is the first to investigate whether this noise has any effect on a bird's beak.

The researchers tested a songbird, the zebra finch, for the study (Taeniopygia guttata).

Males have white, black, gray, orange, and brown plumage, whereas females are uniformly gray.

Males have bright red beaks, while females have orange beaks.

Their beak ornamentation is a social signal as well as a secondary sexual trait that can indicate the quality of a male and influence female mate preference.

Male zebra finch dominance hierarchies are also influenced by beak color.

Because previous research had produced conflicting results, the FAU researchers conducted two separate experiments to determine the effects of anthropogenic noise on cognition, beak color, and growth in zebra finches.

Adult zebra finches were tested on a battery of cognition assays while exposed to playbacks of urban noise versus birds tested without noise in the first experiment.

In the second experiment, researchers assessed the cognitive performance of adult zebra finches on the same foraging tasks after exposing them to urban noise consistently.

They compared their performance to that of birds raised with "pink noise" (a type of noise control) or with normal aviary sounds.

They also tracked the birds' growth and beak color development during their first 90 days of life, and then tested them on a battery of cognition essays once they reached adulthood.

The study's findings, which were published in the journal Acta Ethologica, revealed that urban noises caused the birds to take longer to learn a novel foraging task and an association-learning task.

While exposure to urban noise during development did not affect growth rate or adult body size, treated males developed less bright beak coloration and treated females developed brighter orange beak coloration than untreated birds.

Male finches exposed to normal aviary sounds had brighter beaks at day 90 compared to the urban and pink noise treatment groups, while females had more red-hued beaks at day 90 in the urban and pink noise treatment groups.

The beaks of juvenile zebra finches are black and begin to change color at about one month of age, typically reaching adult color at about 65 days of age.

This is likely why the researchers did not detect any effects of urban noise on male finches.

Also Read: Zebra Finch Embryos Prepare for Climate Change by Listening to Their Parents

Noise pollution is hurting animals

Noise is a distracting, scary, or extremely painful sound. Noise's effects on humans range from mild annoyance to learning and memory issues, sensorineural hearing damage, and heart disease.

To protect human hearing, excessively loud noise is controlled, such as at music concerts or construction sites. But noise is not regulated for other animals, as per The Conversation.

A recent paper by Fay Clark, a Research Fellow at Anglia Ruskin University, discovered that there is a greater knowledge and awareness of how noise harms pets, farm and working animals, and zoo animals.

Decibels are commonly used in research to measure how loud a noise is (dB). Decibels are easily measured with a handheld device and serve as the foundation for human health guidelines.

However, the type of noise source, frequency (pitch), rate, and duration can all have an effect on how a listener perceives noise.

Although great apes and humans have similar hearing abilities, the rest of the animal kingdom perceives noise very differently.

The frequency range of hearing ranges from very high-frequency ultrasound (>20,000 Hz) echolocation in bats and dolphins to very low-frequency infrared (20 Hz) in elephants.

Humans have a hearing range that falls somewhere between ultrasonic and infrared.

Some invertebrates, such as hunting spiders, use tiny leg hairs to detect sound from vibrations.

It's difficult to determine how sensitive an animal is to noise, but what matters most is whether the noise in their environment is within their hearing range, rather than whether the animal has a high or low frequency.