Sounds of Rana aurora - Northern Red-legged Frog

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Adult frog

A male frog calling from about
12 inches underwater.

Breeding habitat

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California

Northwest

Advertisement Calls

An advertisement call is the most well-known call of a frog. It is produced by a male during the breeding season to attract females of his own species. It can also serve an agressive function to defend his calling site by warning rival males of his presence. Frogs usually make the calls around bodies of water that are suitable for breeding and egg laying. These calls can be heard during the evening and at night, and sometimes during daylight at the peak of the breeding season.

The vocalizations of Rana aurora can be described as a weak series of 5 - 7 notes, sounding like uh-uh-uh-uh-uh, lasting 1 - 3 seconds. Calls are made during the day or night for only one or two weeks at a location. Calls are made underwater and are easily missed. They may also be made in the air.

In-Air Recordings

The following recordings were made from 1 to 3 PM on a partly cloudy day in Lewis County Washington in early February. Air temperature was 50 degrees. The elevation was approximately 200 ft. All sounds were recorded in the air (not underwater) at a close distance with a shotgun microphone.

The habitat (shown to the left) was a small overflow pool beside a creek flowing next to fallow agricultural fields in a narrow valley surrounded by forested hills. Several R. aurora egg masses were floating in the water, or attached to grass. Pictures of these eggs can be seen here.

The frogs called from hidden locations underneath vegetation in the water or at the edge of the water. The frogs were probably calling from underwater or with their heads just barely out of the water. The calls were very faint, only audible from a few feet away, and infrequent, lasting only for a few seconds between long stretches of silence.

Background sounds include: various birds calling and moving around in dry reeds, including ravens and song sparrows; flowing water; distant traffic; and distant farm equipment.

This is a 5 second recording of the advertisement calls of a single frog.

This is a 37 second recording of the advertisement calls of a single frog. The loud call note of a Song Sparrow is heard in the second half.

This is a 72 second continuous recording of a few frogs calling or chuckling rapidly - a faster and higher-pitched sound from the typical calls which can be heard above.

This is a 9 second recording of a frog making rapid chuckling and squeaking sounds. (This does not appear to be an advertisement call, so it might be some type of release or encounter call.) A Song Sparrow is singing in the background.

Underwater Recordings

The following recordings were made during an afternoon in early March in Maureen Krinsky's artificial pond in Huboldt County. The air temperature was about 50 degrees, with sun and scatterd clouds. Even though one of the calling frogs was visible about a foot below the surface of the water - see the picture to the left - no sounds were heard in the air. All sounds were recorded with a hydrophone, which is an underwater microphone.

This is a 26 second continuous underwater recording of the advertisement calls of a single frog - shown to the left.

This is a 27 second continuous underwater recording of the advertisement calls of a single frog.

This is a 42 second continuous underwater recording of two or three frogs which appear to be reacting to each other with chuckling and grunting sounds.

This is a 14 second continuous recording of two frogs calling and chuckling.

The following recordings were made at the same location as above in Lewis County, Washington in mid February two years later, using a hydrophone placed only a few inches below the surface. These calls were barely audible in the air, and were very faint underwater, as far as I could determine. 6 or 7 frogs were calling from the area, but the calls were infrequent with long stretches of silence between them.

This is a 2 second underwater recording of the advertisement calls of a single frog.

This is an unedited 21 second underwater recording of a series of 3 advertisement calls of a single frog.

This is a 47 second underwater recording of the advertisement calls of one or more frogs. Several calls from have been edited together.

Waveform and Sonogram

This is a recording of the advertisement calls of a Northern Red-legged Frog recorded underwater in Humboldt County. The image on the right is a visual representation of this call. Click on it to see a larger image. Click here for information about how to read the waveform and sonogram images.

You can listen to more recordings of Northern Red-legged Frogs on this cd:

Carlos Davidson - Frog and Toad Calls of the Pacific Coast - Cornell Laboratory of Ornithology

and on the cd that comes with this book:

Lang Elliott, Carl Gerhardt, and Carlos Davidson - The Frogs and Toads of North America - Houghton Mifflin Harcourt.

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