Intro Flashcards
Ecological importance of birds
Pollinators, fruit dispersal, carcass removal (ecosystem services), regulation of prey services, ecosystem engineers
Economic importance of birds
Food
Hunting
Pest control which prevents crop damage
Tourism
Functions of feathers:
Flight, insulation, coloration and display, body form and protection, waterproofing, shade, support/steering, sensory functions, prey capture, sound production, feather care, water transport.
Flight
Involves the wing (remiges) and tail (rectices) feathers.
Insulation
Has a denser plumage in cold climates. Thus more feathers in winter, which also changes structure. It uses muscles in order to raise and lower feathers to alter insulation properties.
Contour feathers
Feathers on the surface of the body.
Coloration and display
Dependent on the contour feathers.
Body form and protection
General contour feathers provides body protection.
Waterproofing
Aided by a secretion from the preen gland which also has antibacterial functions.
Sensory functions
Filoplumes detects changes in feather angles
Prey capture
Bristle baskets in aerial feeders.
Carotenoids
Yellow and red pigments are created by carotenoids.
Melanins
Blacks and Browns are created by melanins.
Combinations of melanins and carotenoids
Olive green pigments are formed.
Structural colors
Greens and blues are created by prismatic scattering. The colors are created when light enters a feather and is refracted by a complex system of vacuoles within the feather barbs.
Iridescence
Another structural color effect.
A shimmering of color on some birds feathers.
Morphological adaptations for flight
Hollow bones which often have internal struts or trusses that make them very strong however flightless birds have solid bones. The bones are usually thin with many of them fused together to provide increase rigidity. It has lightweight beaks and most teeth.
It has a synsacrum which is the pelvic girdle and the lower spine fused together. It has no bladder and only one ovary. The reproductive organs regress when breeding.
Physiological adaptations for flight
It is energetically demanding therefore it requires a four chambered heart. It uses a lot of oxygen thus the lungs are linked to air sacs that extends through bones. There is a constant flow of air through the lungs during inhalation and exhalation.
Vision
High flight speeds require good vision and swift reaction. The largest portion of the brain is allocated to flight coordination. Their vision is generally tetra chromatic. Able to detect into UV.
Tetrachromacy
The condition of possessing four independent channels for conveying color information or having four types of cone cells in the eye.
Movement/migration
Have built in GPS in order to translocation and find their way home. The need to migrate is genetic however they only learn on their first migration. They orientate by the stars, Suns, magnetic field and local landmarks which are learned. They can evolve rapidly to new habitats.
Bird reproduction
All birds lay Cleidoic eggs. The clutch size depends on the survival rate, latitude etc. most birds are central place foragers which encourages bi-parental care and monogamy, but they have a wide range of social structures including polygyny and polyandry. They can be socially complex, including cooperative breeding. They are sometimes also brood parasites. Chicks are categorized as altricial or precocial.
Brood parasites
Organisms that rely on others to raise their young.
Altricial
Hatched or born in an underdeveloped state and requiring care and feeding by the parents.
Precocial
Hatched or born in an advanced state and able to feed itself almost immediately.
Song and Communication
Most sound is created by the syrinx. It is most developed in oscine passerines. Song is innate in most lineages but learned in some songbirds, parrots and hummingbirds. Learning requires exposure to model songs, meaning learning is better when a tutor is present.
Syrinx
The muscular chamber with multiple tympanic membranes at the lower end of the trachea.
Tympanic
A thin, semitransparent membrane, nearly oval in shape, that belongs to the tympanum.
Tympanum
The eardrum
Oscine passerines
Songbirds
Hearing
They have no external ears although their inner ear has a cochlea which is not spiral.
Oilbirds echo locate like bats.
Tytonidae (Owls)
Have assume tribal ear openings to fix the source in the horizontal and vertical plane, which allows them to catch mice in complete darkness.
Scent and touch
Although not a primary modality for most birds, scent is important for some namely new world vultures, petrels, kiwis.
Their external nares are usually simple and are absent in some taxa but are more complex in some and are uniquely on the bill tip in kiwis.
There are chemotactile receptors in the bill tips of probers.
External nares are absent in
Cormorants and gannets.
Chemotaxis
The movement of an organism in response to chemical stimulus.
