Sound the Alarm: How Birds Send and Spread a Warning

Sound the Alarm:

How Birds Send and Spread a Warning

Scott KiesterElm Fork Chapter

Before We started:Just A Bit if Physics; Pressure Waves and The Waveform

2

A Bit More; Amplitude and Frequency

3

And A Bit More; Band Width

4

And Just One Bit More; Sound Attenuation

I = P / 4 π r 2Let’s just say that alarm are calls made up of lower

frequency sounds that have broad bandwidth which travel further and are absorbed less by solid objects.

And of course there is a glaring exception that we’ll get to a couple of slides from here.

5

Sonograms: Sound Made VisibleSonograms are visual representations of bird songs and calls.

Frequency is the vertical axis Time is the horizontal axis. Fox Sparrow Song

6

Mobbing: Safety in Numbers

https://youtu.be/Ob7-JswKXuI7

The Seet Call; The Exception to the Rule

American Robin

Carolina Chickadee

Tufted Titmouse

Song Sparrow

8

An Interview with Dr. Erick Greene Courtesy of The Cornell Lab of Ornithology

Alarm calls can travel at speeds exceeding 100 miles per hour, giving birds advance warning to take cover.

Dr. Erick Greene says it’s a wonder predators ever beat the system. “It’s really hard to be a hawk. You’re hunting and flying around, trying to find your dinner, and yet there’s this bow wave of information that travels out in front of you faster than you can ever fly.”

9

Alarm Calls of Some Common Texas Birds

10

Northern Cardinals

A typical “TINK” alarm

11

A typical Chip Contact call

American Robins

Peek and Tut alarmsto warn of a ground predator; possibly a cat It is often heard near nests

The Seet Call warning of a flying predator

12

Northern Mockingbirds

The “Hew” Call;a Harsh SKEEH!

13

Downy Woodpeckers

A loud PIK alarm call

A softer slower tempoPIK is typical of abird to bird contact call

14

Carolina and Bewick’s Wrens: Scolding from the bushes

Carolina

Bewick’s

15

Tufted Titmouse

The Seet Call

Mobbing “chickadee” Call

16

Bluejays

“Jeer” Mobbing Call

“Jeer” “Howdy” Call

Cooper’s Hawk Mimicry

17

“Pump Handle”; a Low Intensity Alarm Call

https://www.youtube.com/watch?v=VRXhdz8vZ7U

American CrowsShort Caw: A General Alarm Call

Harsh Caw: Associated with Predator Mobbing

18

Carolina ChickadeesSeet or “High Zee” Call

A single bird giving an alarm

19

Chickadees mobbing a predator

The Chick-a-dee Call:Variations on a Theme

20

Helpful FriendsChipmunks

Grey Squirrels

Aerial Predator

Terrestrial Predator

21

Suggested Reading/Viewing

22