Article contributed by Jon Young, author of What the Robin Knows: How  Birds Reveal the Secrets of Natural World

Shapes of Alarms gives us patterns to look for to refine our understanding of bird language.

In this article, we will look at the specific patterns of vocalizations combined with behaviors in the context of a variety of possible “unwanted visitors” to your neighborhood. The combination of sound, motion and species involved make a dynamic, moving and living “track”. The birds and wildlife reveal the “shape of an alarm” or disturbance caused by a person, bird or animal (usually a threat to their life or their offspring).

When we learn to recognize a few shapes, we can often figure out “who’s causing the alarm” over there--perhaps unseen by us at first. The birds and animals making up the shape are like the sand that reveals the track. They are a living, breathing and dynamic substrate for the “tracks” of disturbance. 

This is an old skill, part of the knowledge base of indigenous hunter-gatherers especially living side-by-side with large and other dangerous wildlife such as tigers, lions, leopards, hyenas, grizzly bears, cougars and poisonous snakes. This skill was originally taught to me, and further refined by my mentors among indigenous tribes. However, the best teachers have been the birds and animals in my own backyard! 

1) Bird Plow

In Voices of Birds, the example I share of walking out my door and startling the juncos that we're feeding right by my car on the grass illustrates a specific shape. As they fly off, they issue a twitter and pump their tails to flash a white flag as they're flying away from me in an upward trajectory. We call that particular behavior the Bird Plow shape. 

The Bird Plow can be caused by many things. For instance, a car driving down the street flushes birds that are on or along the road. They fly off in that same upward trajectory, while squirrels dart away and often up a nearby tree. 

The sudden appearance of a hunting Cooper's hawk diving into a similar scene will cause all the birds to “plow”. That is they will quickly fly off and up and into cover. A variation on the Bird Plow, a Cooper’s hawk hunting will also cause birds to dive downward into a thicket. 

Basically, a Bird Plow is usually indicative of a sudden appearance--bursting a bubble of what was a baseline moment with a startling and sudden appearance. 

There’s yet other variations of this shape. While taking a walk in my on a sunny, warm day. I see the sudden darting of lizards ahead of me. Since lizards are on the ground, sunning themselves and I haven't yet caught them by eye, they startle and dart before I see them. This is a Lizard Plow. 

The Bird Plow is a shape that we don't want to cause when we're birding or when we're trying to observe animals in nature. 

2) Moving Parabolic and Cat Shape

When a cat walks through a yard, a group of birds gang up and mob the cat with sounds and motions. All will try to keep a certain distance from that cat. They'll dive down at it and even strike the cat behind its head. A mockingbird will often do this. The birds mobbing the cat know their limits so they stay high enough above the cat so it cannot jump up and catch them. The distance they maintain also gives the birds a small headstart in time to fly up higher if they need to. 

Maintaining that distance while mobbing, birds will follow that cat as they continue to dive and scold. We sometimes call this alarm the Umbrella Shape, or a Moving Parabolic.  

This slowly moving umbrella shaped alarm is what a leopard gets when it's walking through the Okavango Delta thickets in Botswana. The local guides know this shape well. I have been witness to this when I am guiding tourists there. We can actually find the leopard by looking for, and listening for, that umbrella shape alarm moving through the thickets--where the leopard remains mostly hidden from view.

The Cat Alarm is also witnessed for a mountain lion moving by day in California, or a tiger moving by day in India. This same alarm would be given to a bobcat on the prowl.

Generally it’s the body language and hunting intent of the cat whatever which broadcasts in a way that irritates the songbirds and squirrels nearby. One could say that the Moving Parabolic alarm is reserved for animals who have a hunting intent and behavior. 

3) Static Parabolic

When a great horned owl flies up into a tree and lands in daylight, much to its dismay, it's suddenly surrounded by chickadees gathered in the same umbrella shape above it. The chickadees are vigorously scolding the owl. This, in turn, usually draws in robins and jays who come and join the scold. Soon enough, the crows come in and take over. But all of them basically maintain that umbrella shape over the owl. 

In the wintertime, when there's no nesting protection going on, I can often find screech owls or saw whet owls, pygmy owls, barn owls, barred owls or great horned owls by looking and listening for that umbrella shape of concentrating mobbing. This is often centered in a thick tree like a redwood or Douglas fir in winter for the bigger owls. Sometimes I detect this shape in a bush down low, often revealing one of the smaller owls.

The parabolic shape of birds above what you can't see is a very useful shape to know. It will help you find all sorts of things. In the Kalahari of Botswana, and friend and I were able to find a Mamba in a tree, looking to rob the nest of some gray headed sparrows. The forked tailed drongo was in the mob as well.

The Static Parabolic applies to any nest predator in nesting season. During this time of year, out in your yard you will likely see and hear groups of birds intensely calling and maintaining that umbrella shape up in a tree in your yard. Look for a crow or raven, coming in to see if the robin's nest can be found. It might be a tree squirrel, and in cities like Portland, it is sometimes a Norway rat.

The shape and sound stays in the tree in a static way with a lot of intensity when there’s a nest predator around. That nest predator knows there's a nest nearby and is trying to find it. The whole neighborhood of songbirds nearby come together to attempt to drive off the predator. Even nest-robbing birds like jays will complain and mob the larger cousins, like crows and jays. For the jay, the shoe is on the other foot! 

4) Popcorn 

There's some other shapes that are helpful to know. For instance, if you know your house dog is trotting through a trail that's inside of a thicket somewhere near your home, pay attention to two different shapes--the Hook and the Popcorn Shape.  You can hear the jingling of the dogs collar, you know this sound. You see the bushes moving a bit from the dog’s actions. And, you'll eventually notice that the birds that were in that thicket pop up, showing you where the dog is. This is the Popcorn Shape.

Interestingly, a deer trotting through that same thicket will get almost the same exact result. Children named the “popcorn” shape during a nature program. “Hey, look, the birds are popping up like popcorn from the top of the bush.” 

The Popcorn Shape isn't so much about dogs or deer, it's actually about beings that are trotting. The birds are simply flying up for a second, getting out of the way of the approaching animal that might or might not be dangerous. Because the “trotter”is going quickly through the space, they drop back down again to what they were doing a few seconds ago. 

5) Hook

In a Hook, the bird flies up and away where it came from, and unlike a Plow, it lands on a branch and faces the direction from which it flew. The bird seems to be interested or curious about what flushed it. So it sticks around the general area (unlike a Plow). That's the kind of alarm you would like to receive--instead of the plow! If you walk out the door slowly and carefully, and the juncos just outside fly up to a nearby branch, and then turn and look at you--you’re IN! That’s a hook. 

In Popcorn, the birds are flying up individually in what we call a “hook pattern.” This is the “shape within a shape”. A series of Hooks in a line along a trail “performed by” different individual birds sequentially in a line. 

You want the birds to hook because then they feel relatively safe. They will convey less alarm ahead of you to other birds and wildlife. You will start to see more birds and wildlife in familiar places as you get to know these shapes and learn from them yourself.

If you want to learn more, you can always read my book, What the Robin Knows: How the Birds Reveal the Secrets of the Natural World. We've provided you some diagrams with this article that have a few more useful shapes as well, such as Sentinel and Weasel, and the Tunnel of Silence and more on alarms associated with bird-hunting hawks.

Have fun out there! You have lots of time to sit now, if it’s like my situation here, sheltering in place for over a month now. Thank you and wishing you the best. 

Download this guide to see examples of shapes of alarm.