Getting a Lift: How Birds Fly

Wednesday, October 2, 2019
If you asked a room full of people what superpower they would want if they could have anything, at least a handful would answer I want to be able to fly. Because the very idea of freely flying is mesmerizing, isn't it? It is part of what enthrals us about birds. They can freely fly where they please, so how do they manage this?
Wings are essentially modified arms that have been adapted for flight.

Here are some major differences: 
  • the upper arm is shorter and thick, to power the beating of the wings
  • the bend you see in a birds wing is actually its wrist 
  • the last joint in a wing is similar to our hand, but with only one finger bone 
  • this ends up carrying all the long primary flight feathers 
Wings are much bigger than arms when compared to body size, but they are made of feathers and hollow bones which makes them very light. This being said, not all wings are the same. Birds are further adapted to have certain types of wings, depending on their life-history traits. 

Four Wing Shapes: 

1. Elliptical Wing: this wing type is short and broad, highly manoeuvrable with low stall speed. Wingbeat is often rapid with sharp turns, slow speed flight and frequent landing and taking off. This type is common in forest dwellers and can be observed in bats, robins and sparrows. 
Fox Sparrow, which exhibits Elliptical Wing Shape

2.  High-Speed Wings: wings that are designed for speed and can be found on swallows, falcons,     shorebirds and ducks. These birds often make long migrations or feed while flying. They have low drag which results in relatively low energy expenditure during flight. They are efficient for high-speed flights but cannot easily sustain flight at low speeds. 

Purple Martin, member of the Swallow family, they feed in flight on insects
3. High-Lift Wing: allows birds to soar in thermals for hours, which can be observed in Eagles, Hawks and Vultures. Wings are broad but only relatively long and can accommodate taking off in confined spaces, with a high lift, low soaring speed and slow descents. 

Turkey vulture, which can often be observed soaring in thermals
4. Long Soaring Wings: wingspan is often five times that of the body, with a high lift to drag ratio that makes soaring over oceans possible. This can be observed in terns, gulls and other seabirds. These birds usually run to take off with the wind, and can easily land on water. 

A soaring Arctic Tern (Sterna paradisaea)

I am forever amazed at how adapted individual species are to the lifestyles they lead. If only we could all fly! Keep an eye out for different wing shapes and flight styles as fall migration continues. 

I think that birds are special creatures. To me they symbolize the ability to take off and go wherever they please without limit and land constraint. They can travel the world and go places where land walkers can’t. I think they are the most liberated species due to their ability to fly. Samnam Phin, Property manager, The Trustees of Reservations



Warmly, 

Heather 


No comments:

Post a Comment