Bird Adaptations for Flight
Digits greatly reduced/lost
Feathers as the bulk of the wing and tail
Bones of tail reduced into a pygostyle
Flight is powered by breast muscles concentrated at the keeled sternum
Pneumatized bones
Pneumatized bones
hollow structure of bird’s bones that lightens the skeleton for flight
Pygostyle
A structure of reduced and modified tail bones of birds adapted for flight
Two Basic Structures of Bird Wings
Alula: first digit of the wing that spreads away to create a wing slot that redirects air over the upper surface of te wing to help with sailing
Primary Wing Slotting: primary feathers have a distinct constriction near the tips that helps reduced drag
Aspect Ratio of Bird Wings
the ratio between the length (base to tip) and width (front to back) of the wing.
A long narrow wing will have a high aspect ratio.
Camber of Bird Wings
the ventral concavity of the wings surface
4 Types of Wings
Elliptical
High Speed
High Aspect Ratio
High Left
Elliptical
Wings with a low aspect ratio (short and wide) found in dense enviro such as forests used for high maneuveurability.
High Speed
Wings with a med/high aspect ratio (narrow and long) and a VERY LOW camber
falcons and other high speed wings that maximizes thrust by being able to rapidly beat the wing
High Aspect Ratio
wings with a very high aspect ratio (long and narrow), making excellent air foils but will stall at low speeds.
Typical of albatrosses and long distance seabirds that rely on strong winds to increase speeds
High Lift
wings with medium aspect ratio, high camber and obvious primary wing slotting
hawks and eagles that maximize lift with each wing beat
Soaring Types
Static Soaring
Dynamic Soaring
Static Soaring
drift on air currents that rise vertically as a result of thermals or deflection off of mountains.
Fly in circles above the rising current, slowly increasing altitude. They will glide from one pillar of rising air to another.
High lift wings
Dynamic Soaring
Angle wings upward in opposition to horizontally directed wind currents to quickly gain altitude. The bird will then guide downward
High aspect ratio wings
Bird Skull Features
Modified diapsid
Cranial kinesis
Loss of teeth
Keratinized beak
6 Major Types of Carnivorous Bird Bills
Carnivorous (short, strong, hooked)
Carrion feeders (similar to carnivorous but longer)
Fish Eaters
Probing bills (shorebirds)
Sieves (bristles along the margin)
Insect Eaters
3 Types of Fish Eating Bills
Serrated (narrow with serrations for searing fish and a hooked tip)
Dagger-shaped (long, strong, pointed for spearing)
Pelican
Insect Eating Bird Bill TYpes
Small thin (generalists)
Triangular bill
Chisel-shaped
Herbivorous Bird Bills
Fruit eaters (short with a wide gap)
Seed Eaters (short, strong, conical)
Cross-bills (specialized seed that peel the coat)
Nectar feeding (long, extremely thin)
Grazers (chicken-like)
Remiges
asymmetrical flight feathers of the wing that define the shape of the bird’s plummage
Rectrices
symmetrical tail feathers
Semiplume
structurally between contour and down feathers used as insulation
Filoplume
thin elongate feathers that provide sensory info for wind speed/diraction
Ex: proproceptive (sense position of other feathers
Proprioceptive
Feathers that sense the position of other feathers
