Godwits in flight

Massey University’s Dr Phil Battley describes godwits in flight including flapping ability, speed, flying altitudes, streamlining, time taken for non-stop flight and V-formation flight

Point of interest: In this clip, you’ll see a flock of birds flying in V-formation. These are Canadian geese, who, like godwits, use the V-formation.

Transcript

Dr Phil Battley

Godwits are a group of birds that really relies on powered flight for migration. So different types of birds have different structures and do things in different ways. A hawk has very broad wings, and they can soar up on thermals, which are pockets of air that warms up over land. Now, the problem with a thermal, it’s very good over land, but they don’t occur over sea, so a bird that’s travelling over the sea can’t use thermals, and also birds that fly on thermals migrate very slowly typically.

A godwit just gets up and flaps and keeps on flapping and flying, so its flight speed of about 60 kilometres an hour is quite fast. They also use winds wherever possible, so if there are head winds, birds may choose not to migrate. They’ll wait till there are tail winds, and they can probably adjust their altitude to get the best tail winds.

There are records of godwits migrating at sea level, and there are records of godwits migrating at very high altitudes recorded by radar. We think they can probably go anywhere between about maybe half a kilometre and 3 or 4 kilometres high in order to get the best winds behind them, and we know that, on occasion, when godwits have good winds behind them, they can travel at up to maybe 100 kilometres an hour, so they might be sitting there with a 30 or 40 kilometre an hour tail wind and flying fast as well. They fly for 7 days, and that’s amazing.

When a bird is flying, it’s in its interest to have the lowest resistance that it can, so its feathers are very sleek and the body is very streamlined. There’s a certain profile that creates the least drag. They are sort of tapered, pointed animals that just slice through the air. Their wings are very thin, horizontally, and if you ever have a bird’s wing in your hand from a specimen and you slice it through the air, it’s incredible how well it cuts through it. That’s what it needs to do.

But it still does take some effort, and this is why, when a flock is flying in a V-formation, the bird at the front is cutting into the wind first, and the other birds are passing into wind that has already been sliced to a degree, so the bird at the front is overcoming a bit more of the resistance than the birds behind it are, so they then find it a bit easier and the flock as a whole does a bit better.

Acknowledgements:
Pete & Judy Morrin Productions
Keith Neff