An aeroplane, when it leaves the ground, 'takes off'. What does a bird do?

My daughter recently had the experience of a large bird hitting her car windscreen, and smashing it, when she was doing about 70mph on a motorway. Fortunately the bird did not come through the screen, and there was no damage to life or limb (other than presumably to the poor bird).

As she was near Liverpool her first thought was that it had been a seagull, and later a pigeon. But the person who fitted a new windscreen said he thought it was a pheasant, as they are apparently notorious for this problem. The reason, he explained, is that pheasants have a shallow 'take-off' path. They run along the ground to get airborne.

But it made me wonder whether birds 'take-off'. Is there no other way of describing their going from rest into flight? Should it be 'take flight'?

Actually, take-off is the proper term for that stage of bird flight.

I remember reading about take off angles in wild turkeys and bred turkeys (to stock the forests), that wild turkeys had a steeper angle of incline than those that were raised in sanctuaries. From this, they could tell how much interbreeding was being done in the wild after release (the more wild genes, the steeper).

An article in the Journal of Experimental Biology (Effects of Body Size on Take-off Flight Performance in Phasianidae [Aves]) studied take off angles in Pheasants and other birds in that family.

They cite other studies of bird take offs from hummingbirds to swans...

...this trend will explain aspects of the ecology and evolution of flight. For example, within the Anseriformes, teal (Anas spp.) take off vertically while swans (Cygnus spp.) take off in a laboured manner, with a shallow initial angle of ascent. Since teal require less room than swans for take-off, teal may utilize smaller ponds with less open surface area...

before getting down to their own work:

To evaluate the mechanisms responsible for relationships between body mass and maximum take-off performance in birds, we studied four species in the Phasianidae: northern bobwhite (Colinus virginianus), chukar (Alectoris chukar), ring-necked pheasant (Phasianus colchicus) and wild turkey (Meleagris gallopavo).

One of their conclusions (a simple one comparatively):

Take-off power (Pta) scaled in proportion to m^0.75 and pectoralis mass-specific Pta declined with increasing body mass, roughly in direct proportion to wingbeat frequency.

From another study from the scientific literature (this one measuring seasonal differences and take-off angles):

In particular, the ability to initiate flight through jumping is critical to predator avoidance and may be influenced by changes in body mass (Mb). Here we investigate seasonal differences in the jump take-off performance of high Arctic Svalbard rock ptarmigan (Lagopus muta hyperborea)...

Anyway, you get the picture. Apparently ornithologists refer to 'lift off' as take off (with or without the hyphen). It starts with the first downbeat of the wings once the feet are no longer in contact with any surface.

'Take flight' is the term you're looking for.

Although the wikipedia page for 'Bird flight' repeatedly uses 'Take off' or 'Taking off', so this seems to be a perfectly acceptable usage.

Here's an Ngram for 'Take Flight'