Genetically Modified Birds
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Fig. 4. A broad breasted wild Turkey.
Source: [4]
(b)
Carinate: The flying birds.
However, based on development, birds are classified into 4, namely; precocious, semi precocious altricial and
semi altricial.
Precocial And Altricial Young: Two words describing the degree of development in young birds at hatching
are precocious and altricial. A precocial bird is capable of moving around on its own soon after hatching.
Altricial means incapable of moving around on its own soon after hatchling. Nidicolous is used to describe
young that remain in the nest. All nidifugous birds are precocial, but some nidicolous birds are precocial and
they remain in the nest even though capable of locomotion [8].
Instead of a sharp dividing line between hatchlings that are precocial and those that are altricial, there is
a gradient of precociality. In this guide, we recognize the following categories of young:
Precocial youngs are hatched with eyes open, covered with down, and leave the nest within two days.
There are four levels of precociality, although only three are found in North American birds. Level 1 of
development (precocial 1) is the pattern found in the chicks of megapodes (Australian Malee fowl, Brush
Turkeys, etc.), which are totally independent of their parents. The megapode young are incubated in huge piles
of decaying vegetation, and upon hatching dig their way out, already well feathered and able to fly. No North
American birds show this extreme precociality. Precocial 2 development is found in ducklings and the chicks of
shorebirds, which follow their parents but find development is found in ducklings and the chicks of shorebirds,
which follow their parents but find their own food. The young of game birds, however, trail after their parents
and are shown food; they are classified as precocial 3. Precocial 4 development is represented by the young of
birds such as rails and grebes, which follow their parents and are not just shown food but are actually fed by
them.
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