Why do Birds Fly in Circles? (Uses of Thermal)

Why do Birds flying hours together in circles? and also in various forms and shapes led my passion to read, research on it.

Birds fly in a circle within the thermal region because there where the upward rising air column pushes the birds at higher altitudes without the need for birds to bring a lot of effort into flight. so they simply fly in circles inside the thermal. 

What Is Thermal?

Thermal or warm and upward rising air occur in circular, column forms, therefore birds need to be inside this circle for easy upward motion and so they can stay and fly in a circle pattern to stay within thermals. The bigger the thermal, the bigger the circle of birds with less effort flying.

The air in contact with the ground starts to absorb heat from the ground, thereby becoming warmer and less dense than the uneven surrounding air, resulting in column rise of air known as thermals.

Birds require less energy or effort to reach heights within the thermal area.  Like the fish that spend less energy while traveling in the direction of river flow, similarly, birds often use warm and rising air to reach some heights with the expenditure of limited energy in an upward direction called thermals.

As you know the hot air balloon rises while lifting you at higher altitudes(height) due to warm air inside these balloons, Similarly, a certain larger volume of air on the ground heats up due to solar radiation and also becomes less dense than the surrounding air, allowing the warm air to rise in column-wise while also lifting anything like birds, glider, or kites in their direction. 

Why Do Birds Use Thermal?

To fly easily, birds use thermals. Since it takes less energy for birds to fly within thermal simply the warmer air in rising relative to flying in non-thermal, so it is obvious to use thermal to fly easily. While birds simply make circles within the thermals, upward rising air columns carry the birds to higher altitudes height, without putting much effort.

Thermals help birds when they are in search of food. That is when it takes a long time for birds such as vultures and eagles to search for food while they are flying for hours together so these birds go into thermals, allowing them to fly easily and longer time till they find foods.

Thermals help migratory birds fly long distances and expend less effort by frequently entering the thermal areas they encounter during migration while on the way toward distant locations. There are other explanations for birds to use thermal items, such as warming the bird’s body in the early morning, etc.

How Do You Identify Thermals?

Soaring birds have a special ability to find thermals, As thermal contain warm air, upward rising air, and less dense air it’s easy for birds to identify thermals and also to differentiate between strong and weak thermals as they switch between them according to their altitude requirements and speed.

Thermals are commonly used by birds such as vultures, raptors, storks, eagles, and migratory birds and are also found using thermals for a longer period of time.

Why do Birds Fly in V Formal?

For birds flying in ‘v’ formation or type, there are many explanations. 

The discovered and typical reasons, however, are to facilitate easy flight, to follow leaders for navigation purposes, and also to save energy during a long flight. The air-current created by other birds creates less turbulence and less drag on the following adjacent birds when flying in ‘v’ patterns, making it easier to fly.

Most birds usually fly in different patterns like ‘v’ formation or ‘v’ shape etc. because the birds can find the best aerodynamic positions, least resistance path through their feathers while flying in flocks as the turbulence and drag caused will be less in these patterns, leads to less energy expense when a bird flies behind and adjacent to the other birds than the bird which flies alone. 

Such adaptation of birds flying and following one another are often used by migrant birds to achieve energy conservation while flying long distances. In order to fly effectively, All birds show certain patterns along with flapping wings synchronously to make flights efficiently.

However, If birds fly alone, it has to put more effort and more energy against air-currants and air-resistance when compared to flying with flocks in certain patterns.

How do Birds Fly?

Birds can fly in different types such as gliding, flapping ann gliding, soaring, hovering, Hawking, etc.

Sl no.Flight patternBird exampleFly mechanism
1.V formationGeese, ducks, and swans.Following adjacent birds uses wind currents of leading birds to conserve energy during flight.
2.Direct Flightducks, herons, shorebirds.Fly in a straight path by  continuously flapping wings
3.HoveringHummingbirds.Hovering due to the formation of up and downstroke.
4.ZigzagSnipes, grouse.Fly up and down.
5.Straight-line formationPelicans, flamingoes, cranes.Flies in a straight path or line
6.Glide Swifts and swallows.Mostly glide.
7.Static SoaringHawks and vultures.Soar then glide and fly in circles.
8.Flap and Glide Ravens, owls, and hawks.Flaps wing and then soar and glides.

Why Do So Many Birds Fly Together?

We have seen hundreds and thousands of birds both small birds flying in circles and big birds flying together for several reasons, some common reasons are, to avoid predator, to make certain patterns and forms in order to fly effectively and efficiently, migration, murmuration, to follow a certain direction, staying in thermals, follow the leading birds who can navigate and guide the rest of the flocks, etc.

“Birds of like feathers flock together.”

What is Murmuration? Flying of hundreds and even thousands of birds in the coordinated pattern together in the sky.

Why do Birds Fly in Circles at Sunset? In order to seek more sunlight at sunset, birds fly in thermals or simply fly to get some sunlight at higher altitudes while also heading towards their home or nests.

Why do Birds Fly in Figure 8?

usually, birds fly circles with clockwise direction or counter-clockwise direction, However, sometimes they consecutively switch between clockwise direction or counter-clockwise direction while flying in a circle causing them to appear in figure 8.

How high can Birds Fly in the Sky?

  • The eagles can reach altitudes(height) of over 10,000 feet.
  • Mallard ducks are known to reach altitudes of 6,401 m.
  • Sparrows and hummingbirds fly at altitudes of 5,000 m.
  • Most vulture species fly at very high altitudes 11,000m.
  • Bar-headed goose can fly at approximately 7,000m.

Why do Birds Fly in Winter?

In winter, the current location where birds live may start to turn cold, or also they may not find food like nectar or insect, etc causing birds to fly to a warmer region where plenty of food available with optimal temperature.

Read More : Why do Pigeons Fly in Circles ?


Where do thermals form? Thermals occur on mountains in the afternoons, due to solar radiation, and also in places where sufficient solar radiation available.

What are birds gliding on without flapping wings? Within thermal areas, soaring birds, such as vultures and some hawks, fly with a few wing flaps or without flapping their wings for long periods.

Why do flocks of birds fly in a circle over the same place over and over again?  Birds flying within the thermals require less energy so birds flying in a circle can be seen in a specific thermal location spiraling in loops or spiraling in the circle when thermals exist for a certain time at specific locations.

What does it mean when birds fly in circles? Birds flying in a circle means they are in search of food or flying or gliding with the help of warm, upward rising wind called thermals without spending more effort.